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Sample records for advanced glycosylation end-products

  1. 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.

  2. 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

  3. 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.

  4. 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

  5. Novel analytical approach to monitoring advanced glycosylation end products in human serum with on-line spectrophotometric and spectrofluorometric detection in a flow system.

    PubMed

    Wróbel, K; Wróbel, K; Garay-Sevilla, M E; Nava, L E; Malacara, J M

    1997-09-01

    We proposed a simple analytical procedure for measurement of serum advanced glycosylation end products (AGEs) based on simultaneous detection of low-molecular-mass peptides and AGEs with a flow system and two detectors connected on-line: spectrophotometric for peptides (lambda = 280 nm) and spectrofluorometric for AGEs (lambda ex = 247 nm, lambda em = 440 nm). Sample pretreatment was carried out in microcentrifuge tubes: Serum (20 microL) was deproteinized with trichloroacetic acid (480 microL, 0.15 mol/L) and lipids were extracted with chloroform (100 microL). Twenty microliters of the filtered aqueous layer was injected to the flow system and the relation between fluorescence and absorption signals was measured. A peptide-derived AGE calibrator was used for calibration. Within-day and between-day CVs were 6.7% and 9.1%, respectively, at an AGE concentration corresponding approximately to that in healthy individuals. Mean results (+/-SD) in 10 healthy individuals were 10.1% +/- 1.0%, in 21 patients with diabetes without complications 18.0% +/- 6.2%, in 25 patients with complications 24.1% +/- 15.4%, and in 12 diabetic patients in end-stage renal disease 92% +/- 30%. Comparison with an ELISA procedure (x, in arbitrary units/L) yields a regression equation y = 0.713x + 1.24 (Sy [symbol: see text] x = 6777, r = 0.8477, n = 41).

  6. Dietary Advanced Glycation End Products and Aging

    PubMed Central

    Luevano-Contreras, Claudia; Chapman-Novakofski, Karen

    2010-01-01

    Advanced glycation end products (AGEs) are a heterogeneous, complex group of compounds that are formed when reducing sugar reacts in a non-enzymatic way with amino acids in proteins and other macromolecules. This occurs both exogenously (in food) and endogenously (in humans) with greater concentrations found in older adults. While higher AGEs occur in both healthy older adults and those with chronic diseases, research is progressing to both quantify AGEs in food and in people, and to identify mechanisms that would explain why some human tissues are damaged, and others are not. In the last twenty years, there has been increased evidence that AGEs could be implicated in the development of chronic degenerative diseases of aging, such as cardiovascular disease, Alzheimer’s disease and with complications of diabetes mellitus. Results of several studies in animal models and humans show that the restriction of dietary AGEs has positive effects on wound healing, insulin resistance and cardiovascular diseases. Recently, the effect of restriction in AGEs intake has been reported to increase the lifespan in animal models. This paper will summarize the work that has been published for both food AGEs and in vivo AGEs and their relation with aging, as well as provide suggestions for future research. PMID:22254007

  7. Advanced glycation end products in renal failure: an overview.

    PubMed

    Noordzij, M J; Lefrandt, J D; Smit, A J

    2008-12-01

    The article aims to present an overview of the existing knowledge on advanced glycation end products (AGE). They are moieties that bind to proteins, but also lipids and nuclear acids. AGE are formed during glycation and oxidative stress. Accumulation of AGE occurs especially in diabetes and chronic renal failure and plays a major pathogenetic role. The deleterious effects of AGE result from cross-linking of proteins and activation of the receptor for advanced glycation end products. AGE accumulation can be noninvasively assessed by the skin autofluorescence reader. In diabetics, the skin autofluorescence predicts cardiac mortality and the occurrence of macro- and microvascular complications. In patients on haemodialysis, skin autofluorescence is highly elevated and predicts mortality. After renal transplantation AGE accumulation is lower than during haemodialysis, but still remains elevated and is a strong risk factor for chronic renal transplant dysfunction. Some of the potential methods to intervene with AGE accumulation are discussed in this article.

  8. Advanced glycation end products in renal failure: an overview.

    PubMed

    Noordzij, M J; Lefrandt, J D; Smit, A J

    2008-12-01

    The article aims to present an overview of the existing knowledge on advanced glycation end products (AGE). They are moieties that bind to proteins, but also lipids and nuclear acids. AGE are formed during glycation and oxidative stress. Accumulation of AGE occurs especially in diabetes and chronic renal failure and plays a major pathogenetic role. The deleterious effects of AGE result from cross-linking of proteins and activation of the receptor for advanced glycation end products. AGE accumulation can be noninvasively assessed by the skin autofluorescence reader. In diabetics, the skin autofluorescence predicts cardiac mortality and the occurrence of macro- and microvascular complications. In patients on haemodialysis, skin autofluorescence is highly elevated and predicts mortality. After renal transplantation AGE accumulation is lower than during haemodialysis, but still remains elevated and is a strong risk factor for chronic renal transplant dysfunction. Some of the potential methods to intervene with AGE accumulation are discussed in this article. PMID:19090900

  9. Advanced glycation end-products inhibitors isolated from Schisandra grandiflora.

    PubMed

    Poornima, B; Kumar, D Anand; Siva, Bandi; Venkanna, A; Vadaparthi, P R Rao; Kumar, K; Tiwari, Ashok K; Babu, K Suresh

    2016-01-01

    Free radicals scavenging and advanced glycation end-products (AGEs) inhibitory potentials in crude chloroform extract of Schisandra grandiflora were evaluated. Bioassay-guided isolation of the chloroform extract led to the identification of 24 compounds. Among the isolates, ( ± ) gomisin M1, arisantetralone C and D, macelignan, saurulignan B and SZ-MO displayed potent-free radical scavenging as well as AGEs inhibitory potentials. This is the first report identifying the presence of AGEs inhibitory activity and assigning AGEs inhibitory activity to these compounds. Therefore, our research finds new application of traditional medicinal plant S. grandiflora having capacity to reduce formation and accumulation of AGEs in diabetes.

  10. 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

  11. 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

  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. Accumulation of advanced glycation end-products in human dentine.

    PubMed

    Miura, Jiro; Nishikawa, Kantaro; Kubo, Mizuho; Fukushima, Shuichiro; Hashimoto, Mamoru; Takeshige, Fumio; Araki, Tsutomu

    2014-02-01

    Cross-linking of collagen by Advanced Glycation End-products (AGEs) occurs by non-enzymatic glycation (Maillard reaction). The purpose of this study was to examine whether AGEs are formed in human dentinal collagen, and to consider any possible influence of AGEs on dentinal physiology. Mechanical characteristics, fluorescence spectra and immunohistochemical analyses of demineralized dentine sections from young subjects were compared with those of aged ones. The same investigations were performed with young dentine artificially glycated by incubation in 0.1M ribose solution. Indentation measurement indicated that the sections from aged dentine were mechanically harder than those from young dentine. The hardness of young dentine increased after incubation in ribose solution. Fluorescence peak wavelength of the young dentine was shorter than that of the aged one, but shifted towards the peak wavelength of the aged one after incubation in ribose solution. These changes were considered to be due to accumulation of AGEs. Existence of AGEs in dentinal collagen was confirmed by immunohistochemical analysis. The obtained results suggest that AGEs accumulation occurs in dentinal collagen and is affected by both human age and physiological conditions such as glucose level in blood because dentinal collagen receives nourishment via dental pulp and tubules. PMID:24370182

  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.

  16. Tissue-Advanced Glycation End Product Concentration in Dialysis Patients

    PubMed Central

    McIntyre, Natasha J.; Chesterton, Lindsay J.; John, Stephen G.; Jefferies, Helen J.; Burton, James O.; Taal, Maarten W.; Fluck, Richard J.

    2010-01-01

    Background and objectives: Tissue-advanced glycation end products (AGE) are a measure of cumulative metabolic stress. Assessment of tissue AGE by skin autofluoresence (AF) correlates well with cardiovascular outcomes in hemodialysis (HD) patients. This study aimed to measure and compare tissue AGE levels in HD and peritoneal dialysis (PD) patients and to evaluate the impact of systemic PD glucose exposure. Design, setting, participants, & measurements: Tissue AGE were measured in 115 established dialysis patients (62 HD and 53 PD) using a cutaneous AF device (AGE Reader; DiagnOptics). Values were compared with an age-matched non–chronic kidney disease database. Review of all previous PD solution delivery/prescription data determined PD glucose exposure. Results: PD patients were similar in age to HD patients but had a shorter dialysis vintage. There were no differences in ischemic heart disease or smoking history, statin or angiotensin-converting enzyme inhibitor (ACEi) use, lipids, biochemistry, or prevalence of diabetes. More than 90% of both groups had met current dialysis adequacy targets. Skin AF values in PD and HD patients were similar and strongly correlated with historical PD glucose exposure. Skin AF correlated with age in both groups but with dialysis vintage only in PD patients Conclusions: Cumulative metabolic stress and transient hyperglycemia results in grossly elevated levels of tissue AGE in dialysis patients. In PD patients, this high level of AGE deposition is associated with historical glucose exposure. This observation provides a previously unappreciated potential link between PD exposure to glucose and systemic cardiovascular disease. PMID:19965551

  17. Advanced glycosylation products quench nitric oxide and mediate defective endothelium-dependent vasodilatation in experimental diabetes.

    PubMed Central

    Bucala, R; Tracey, K J; Cerami, A

    1991-01-01

    Nitric oxide (an endothelium-derived relaxing factor) induces smooth muscle relaxation and is an important mediator in the regulation of vascular tone. Advanced glycosylation end products, the glucose-derived moieties that form nonenzymatically and accumulate on long-lived tissue proteins, have been implicated in many of the complications of diabetes and normal aging. We demonstrate that advanced glycosylation products quench nitric oxide activity in vitro and in vivo. Acceleration of the advanced glycosylation process in vivo results in a time-dependent impairment in endothelium-dependent relaxation. Inhibition of advanced glycosylation with aminoguanidine prevents nitric oxide quenching, and ameliorates the vasodilatory impairment. These results implicate advanced glycosylation products as important modulators of nitric oxide activity and endothelium-dependent relaxation. PMID:1991829

  18. 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

  19. 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.

  20. Advanced glycation end products accelerate ischemia/reperfusion injury through receptor of advanced end product/nitrative thioredoxin inactivation in cardiac microvascular endothelial cells.

    PubMed

    Liu, Yi; Ma, Yanzhuo; Wang, Rutao; Xia, Chenhai; Zhang, Rongqing; Lian, Kun; Luan, Ronghua; Sun, Lu; Yang, Lu; Lau, Wayne B; Wang, Haichang; Tao, Ling

    2011-10-01

    The advanced glycation end products (AGEs) are associated with increased cardiac endothelial injury. However, no causative link has been established between increased AGEs and enhanced endothelial injury after ischemia/reperfusion. More importantly, the molecular mechanisms by which AGEs may increase endothelial injury remain unknown. Adult rat cardiac microvascular endothelial cells (CMECs) were isolated and incubated with AGE-modified bovine serum albumin (BSA) or BSA. After AGE-BSA or BSA preculture, CMECs were subjected to simulated ischemia (SI)/reperfusion (R). AGE-BSA increased SI/R injury as evidenced by enhanced lactate dehydrogenase release and caspase-3 activity. Moreover, AGE-BSA significantly increased SI/R-induced oxidative/nitrative stress in CMECs (as measured by increased inducible nitric oxide synthase expression, total nitric oxide production, superoxide generation, and peroxynitrite formation) and increased SI/R-induced nitrative inactivation of thioredoxin-1 (Trx-1), an essential cytoprotective molecule. Supplementation of EUK134 (peroxynitrite decomposition catalyst), human Trx-1, or soluble receptor of advanced end product (sRAGE) (a RAGE decoy) in AGE-BSA precultured cells attenuated SI/R-induced oxidative/nitrative stress, reduced SI/R-induced Trx-1 nitration, preserved Trx-1 activity, and reduced SI/R injury. Our results demonstrated that AGEs may increase SI/R-induced endothelial injury by increasing oxidative/nitrative injury and subsequent nitrative inactivation of Trx-1. Interventions blocking RAGE signaling or restoring Trx activity may be novel therapies to mitigate endothelial ischemia/reperfusion injury in the diabetic population.

  1. 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

  2. Antihyperglycemic activity and inhibition of advanced glycation end product formation by Cuminum cyminum in streptozotocin induced diabetic rats.

    PubMed

    Jagtap, A G; Patil, P B

    2010-01-01

    Cuminum cyminum is widely used as a spice in many countries. The aim of the present study was to investigate the effect of methanolic extract of seeds of C. cyminum (CC) on diabetes, oxidative stress and formation of advanced glycated end products (AGE) and obtain comparison with glibenclamide. In vitro studies indicated that CC inhibited free radicals and AGE formation. Treatment of streptozotocin-diabetic rats with CC and glibenclamide for 28 days caused a reduction in blood glucose, glycosylated hemoglobin, creatinine, blood urea nitrogen and improved serum insulin and glycogen (liver and skeletal muscle) content when compared to diabetic control rats. Significant reduction in renal oxidative stress and AGE was observed with CC when compared to diabetic control and glibenclamide. CC and glibenclamide improved antioxidant status in kidney and pancreas of diabetic rats. Diabetic rats showed increase in rat tail tendon collagen, glycated collagen, collagen linked fluorescence and reduction in pepsin digestion. Treatment with CC significantly improved these parameters when compared to diabetic control and glibenclamide group. Though the antidiabetic effect of CC was comparable to glibenclamide it had better effect in controlling oxidative stress and inhibiting the AGE formation, which are implicated in the pathogenesis of diabetic microvascular complications.

  3. 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

  4. 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

  5. Glycosyl iodides. History and recent advances.

    PubMed

    Meloncelli, Peter J; Martin, Alan D; Lowary, Todd L

    2009-06-12

    The use of glycosyl iodides as an effective method for the preparation of glycosides has had a recent resurgence in carbohydrate chemistry, despite its early roots in which these species were believed to be of limited use. Renewed interest in these species as glycosylating agents has been spurred by their demonstrated utility in the stereoselective preparation of O-glycosides, and other glycosylic compounds. This review provides a brief historical account followed by an examination of the use of glycosyl iodides in the synthesis of oligosaccharides and other glycomimetics, including C-glycosylic compounds, glycosyl azides and N-glycosides.

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

    PubMed

    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.

  7. 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

  8. New advanced glycation end-products inhibitors from Dichrostachys cinerea Wight & Arn.

    PubMed

    Suresh, G; Tiwari, Ashok K; Radha Krishna Murthy, M; Anand Kumar, D; Rajendra Prasad, K; Ranga Rao, R; Zehra Ali, A; Suresh Babu, K

    2012-01-01

    Free radical scavenging and advanced glycation end-product (AGE) inhibitory potential were evaluated in the crude methanol extract of Dichrostachys cinerea. Bioassay-guided isolation led to the identification of four flavan-3-ols, namely (-)-mesquitol (1), oritin (2), (-)-festidinol (3) and (-)-epicatechin (4). Analysis of structure-activity relationships revealed that the presence of 7,8-dihydroxyl groups in the A-ring of flavan-3-ols in conjunction with 3',4'-dihydroxyls in the B-ring (1) is an important criterion for displaying potent AGE inhibitory activity along with free radical scavenging properties. (-)-Mesquitol (1), oritin (2), and (-)-festidinol (3) were found to be new natural AGE inhibitors. (-)-Mesquitol (1) displayed the most potent AGE inhibitory activity. Results suggest that (-)-mesquitol (1) may serve as an important natural organic lead compound for future development of antiglycating agents along with potent antioxidant activity.

  9. Advanced glycation end products (AGEs) and their receptor (RAGE) system in diabetic retinopathy.

    PubMed

    Yamagishi, Sho-ichi; Nakamura, Kazuo; Matsui, Takanori

    2006-03-01

    Vascular complications are a leading cause of 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. There is a growing body of evidence that formation and accumulation of advanced glycation end products (AGEs) progress during normal aging, and at an extremely accelerated rate in diabetes, thus being involved in the pathogenesis of diabetic vascular complications. Furthermore, the interaction by AGEs of their receptor, RAGE, activates down-stream signaling and evokes inflammatory responses in vascular wall cells. Therefore, inhibition of AGE formation or blockade of the RAGE signaling may be a promising target for therapeutic intervention to prevent diabetic vascular complications. This review discusses the molecular mechanisms of diabetic retinopathy, especially focusing on the AGE-RAGE system. Several types of inhibitors of the AGE-RAGE system and their therapeutic implications are also reviewed here. PMID:16712466

  10. Receptor for Advanced Glycation End Products (RAGE) Deficiency Attenuates the Development of Atherosclerosis in Diabetes

    PubMed Central

    Soro-Paavonen, Aino; Watson, Anna M.D.; Li, Jiaze; Paavonen, Karri; Koitka, Audrey; Calkin, Anna C.; Barit, David; Coughlan, Melinda T.; Drew, Brian G.; Lancaster, Graeme I.; Thomas, Merlin; Forbes, Josephine M.; Nawroth, Peter P.; Bierhaus, Angelika; Cooper, Mark E.; Jandeleit-Dahm, Karin A.

    2008-01-01

    OBJECTIVE—Activation of the receptor for advanced glycation end products (RAGE) in diabetic vasculature is considered to be a key mediator of atherogenesis. This study examines the effects of deletion of RAGE on the development of atherosclerosis in the diabetic apoE−/− model of accelerated atherosclerosis. RESEARCH DESIGN AND METHODS—ApoE−/− and RAGE−/−/apoE−/− double knockout mice were rendered diabetic with streptozotocin and followed for 20 weeks, at which time plaque accumulation was assessed by en face analysis. RESULTS—Although diabetic apoE−/− mice showed increased plaque accumulation (14.9 ± 1.7%), diabetic RAGE−/−/apoE−/− mice had significantly reduced atherosclerotic plaque area (4.9 ± 0.4%) to levels not significantly different from control apoE−/− mice (4.3 ± 0.4%). These beneficial effects on the vasculature were associated with attenuation of leukocyte recruitment; decreased expression of proinflammatory mediators, including the nuclear factor-κB subunit p65, VCAM-1, and MCP-1; and reduced oxidative stress, as reflected by staining for nitrotyrosine and reduced expression of various NADPH oxidase subunits, gp91phox, p47phox, and rac-1. Both RAGE and RAGE ligands, including S100A8/A9, high mobility group box 1 (HMGB1), and the advanced glycation end product (AGE) carboxymethyllysine were increased in plaques from diabetic apoE−/− mice. Furthermore, the accumulation of AGEs and other ligands to RAGE was reduced in diabetic RAGE−/−/apoE−/− mice. CONCLUSIONS—This study provides evidence for RAGE playing a central role in the development of accelerated atherosclerosis associated with diabetes. These findings emphasize the potential utility of strategies targeting RAGE activation in the prevention and treatment of diabetic macrovascular complications. PMID:18511846

  11. Advanced glycation End-products (AGEs): an emerging concern for processed food industries.

    PubMed

    Sharma, Chetan; Kaur, Amarjeet; Thind, S S; Singh, Baljit; Raina, Shiveta

    2015-12-01

    The global food industry is expected to increase more than US $ 7 trillion by 2014. This rise in processed food sector shows that more and more people are diverging towards modern processed foods. As modern diets are largely heat processed, they are more prone to contain high levels of advanced glycation end products (AGEs). AGEs are a group of complex and heterogeneous compounds which are known as brown and fluorescent cross-linking substances such as pentosidine, non-fluorescent cross-linking products such as methylglyoxal-lysine dimers (MOLD), or non-fluorescent, non-cross linking adducts such as carboxymethyllysine (CML) and pyrraline (a pyrrole aldehyde). The chemistry of the AGEs formation, absorption and bioavailability and their patho-biochemistry particularly in relation to different complications like diabetes and ageing discussed. The concept of AGEs receptor - RAGE is mentioned. 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). Different methods of detection and quantification along with types of agents used for the treatment of AGEs are reviewed. Generally, ELISA or LC-MS methods are used for analysis of foods and body fluids, however lack of universally established method highlighted. The inhibitory effect of bioactive components on AGEs by trapping variety of chemical moieties discussed. The emerging evidence about the adverse effects of AGEs makes it necessary to investigate the different therapies to inhibit AGEs.

  12. Role of myosin light chain and myosin light chain kinase in advanced glycation end product-induced endothelial hyperpermeability in vitro and in vivo.

    PubMed

    Wu, Fan; Guo, Xiaohua; Xu, Jing; Wang, Weiju; Li, Bingling; Huang, Qiaobing; Su, Lei; Xu, Qiulin

    2016-03-01

    We have previously reported that advanced glycation end products activated Rho-associated protein kinase and p38 mitogen-activated protein kinase, causing endothelial hyperpermeability. However, the mechanisms involved were not fully clarified. Here, we explored the role of myosin light chain kinase in advanced glycation end product-induced endothelial hyperpermeability. Myosin light chain phosphorylation significantly increased by advanced glycation end products in endothelial cells in a time- and dose-dependent manner, indicating that myosin light chain phosphorylation is involved in the advanced glycation end product pathway. Advanced glycation end products also induced myosin phosphatase-targeting subunit 1 phosphorylation, and small interfering RNA knockdown of the receptor for advanced glycation end products, or blocking myosin light chain kinase with its inhibitor, ML-7, or small interfering RNA abated advanced glycation end product-induced myosin light chain phosphorylation. Advanced glycation end product-induced F-actin rearrangement and endothelial hyperpermeability were also diminished by inhibition of receptor for advanced glycation end product or myosin light chain kinase signalling. Moreover, inhibiting myosin light chain kinase with ML-7 or blocking receptor for advanced glycation end product with its neutralizing antibody attenuated advanced glycation end product-induced microvascular hyperpermeability. Our findings suggest a novel role for myosin light chain and myosin light chain kinase in advanced glycation end product-induced endothelial hyperpermeability.

  13. Evaluation of autofluorescent property of hemoglobin-advanced glycation end product as a long-term glycemic index of diabetes.

    PubMed

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

    2003-04-01

    Current methods for measuring long-term glycemia in patients with diabetes are HbA(1c) and advanced glycation end products (AGEs), which are estimated by phenyl boronate affinity chromatography and competitive enzyme-linked immunosorbent assay, respectively. In this study, we hypothesize that the intrinsic fluorescence property of hemoglobin-AGE (Hb-AGE) may be a simple, accurate, and therefore better index for long-term glycemic status due to its highly specific nature and longer half-life. To establish this contention, in vitro and in vivo experiments were carried out. The former was performed by incubating commercially available hemoglobin with 5 and 20 mmol/l glucose and the latter through experimentally induced (streptozotocin) diabetes in an animal model (male Wistar rats) to identify the new fluorophore formed due to the nonenzymatic glycosylation of hemoglobin. An adduct exhibiting fluorescence at 308/345 nm of excitation/emission wavelengths has been identified and its time-dependent formation established. Under in vitro conditions, the first appearance of the new fluorophore was noticed only after a period of 2 months, whereas under in vivo conditions, it increased significantly after 2 months of hyperglycemia. Consistent with the observations, studies on patients with type 2 diabetes demonstrated an elevated level of this new fluorescent adduct in patients with persisting high levels of plasma glucose for >2 months. Based on the results obtained, Hb-AGE appears to be an efficient fluorescence-based biosensing molecule for the long-term monitoring of glycemic control in diabetes.

  14. [Advanced glycation and lipoxidation end-products amplify inflammation. The role of a healthy diet].

    PubMed

    Orlando, G; Bengmark, S

    2008-06-01

    Increasing evidence suggests that an unhealthy life style is negatively associated with all chronic diseases (CD). Common to most CD is a more or less permanent exaggerated inflammation associated with increased oxidation, strongly associated with metabolic syndrome and also increased deposition in tissues of advanced glycation and lipoxidation end-products (AGE/ALE). It is suggested that all CD patients, including those suffering from genetic disorders or from diseases of obscure etiology, will benefit from measures to control AGE/ALE. It is likely, but yet not proven, that control of intake and cellular production of AGE/ALE is an important ingredient in a healthy lifestyle, and might further improve outcome. An exaggerated inflammation is also observed in patients who suffer from complications of acute diseases: infections, trauma and advanced surgical and medical treatments such as transplantations. Complications and sequelae to these events are significantly more common in elderly and particularly in those with CD. Much supports that the lifestyle of the patients and degree of inflammation before trauma significantly affects outcome. Recently accumulated knowledge about the link between metabolic syndrome and increased deposition of AGE/ALE in the body supports the suggestion that future attempts to minimize accumulation in the body of such substances might significantly reduce both acute and chronic morbidities. However, the research in this field is at the beginning, and most studies remain to be done.

  15. 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.

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

    PubMed

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

    2015-10-27

    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.

  17. 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

  18. 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

  19. 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

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  4. 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

  5. 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

  6. 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

  7. 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

  8. Effect of advanced glycation end product intake on inflammation and aging: a systematic review.

    PubMed

    Van Puyvelde, Katrien; Mets, Tony; Njemini, Rose; Beyer, Ingo; Bautmans, Ivan

    2014-10-01

    Aging is associated with a chronic low-grade inflammatory status that contributes to chronic diseases such as age-related muscle wasting, kidney disease, and diabetes mellitus. Since advanced glycation end products (AGEs) are known to be proinflammatory, this systematic review examined the relation between the dietary intake of AGEs and inflammatory processes. The PubMed and Web of Science databases were screened systematically. Seventeen relevant studies in humans or animals were included. The intervention studies in humans showed mainly a decrease in inflammation in subjects on a low-AGE diet, while an increase in inflammation in subjects on a high-AGE diet was less apparent. About half of the observational studies found a relationship between inflammatory processes and AGEs in food. When the results are considered together, the dietary intake of AGEs appears to be related to inflammatory status and the level of circulating AGEs. Moreover, limiting AGE intake may lead to a decrease in inflammation and chronic diseases related to inflammatory status. Most of the trials were conducted in patients with chronic kidney disease or diabetes, and thus additional studies in healthy individuals are needed. Further investigation is needed to elucidate the effects of lifetime exposure of dietary AGEs on aging and health.

  9. 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

  10. 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

  11. 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.

  12. 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.

  13. 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

  14. 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.

  15. 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

  16. Arginine-derived advanced glycation end products generated in peptide-glucose mixtures during boiling.

    PubMed

    Frolov, Andrej; Schmidt, Rico; Spiller, Sandro; Greifenhagen, Uta; Hoffmann, Ralf

    2014-04-23

    Glycation refers to the reaction of amino groups, for example in proteins, with reducing sugars. Intermediately formed Amadori products can be degraded by oxidation (Maillard reactions) leading to a heterogeneous class of advanced glycation end-products (AGEs), especially during exposure to heat. AGEs are considered to be toxic in vivo due to their pronounced local and systemic inflammatory effects. At high temperatures, these reactions have been mostly investigated at the amino acid level. Here, we studied the formation of arginine-related AGEs in peptides under conditions simulating household cooking at physiological d-glucose concentrations. High quantities of AGE-modified peptides were produced within 15 min, especially glyoxal-derived products. The intermediately formed dihydroxy-imidazolidine yielded glyoxal- (Glarg) and methylglyoxal-derived hydro-imidazolinones (MG-H), with Glarg being further degraded to carboxymethyl-l-arginine (CMA). Carboxyethyl-l-arginine was not detected. The formation rates and yields were strongly increased in the presence of physiologically relevant concentrations of Fe(II)-ions and ascorbate. A nearby histidine residue increased the content of AGEs, whereas glutamic acid significantly reduced the CMA levels.

  17. Role of Reactive Oxygen Species and Advanced Glycation End Products in the Malfunctioning of Dental Implants

    PubMed Central

    Guo, M; Liu, L; Zhang, J; Liu, M

    2015-01-01

    ABSTRACT Objective: In the last decade, dental implants have emerged as a crucial modality and serve as an individual form of therapy for dental failure. However, disparities in host responses have led to peri-implantitis and implant failure. The pathological mechanisms driving peri-implantitis remain largely unknown. In this study, we evaluated the role of oxidative stress and advanced glycation end products (AGEs) in the progression of peri-implantitis and dental implants failure, compared with chronic periodontal disease. Subjects and Methods: Three patient groups (peri-implantitis, chronic periodontal disease and control), each with 10 subjects (7M/3F) and average age ranging from 40–60 years were selected for analysis. Salivary oxidative stress and tissue AGE levels were analysed by probing for reactive oxygen species (ROS) and Maillard reaction-related fluorescence, respectively. Results: We observed significant increase (> 2-fold) in oxidative stress and AGE levels in patients with peri-implantitis and chronic periodontal disease compared to controls, with chronic periodontal disease having the highest levels. In addition, we observed a strong positive correlation (r = 0.94) between oxidative stress and AGE levels in the patients. Conclusion: We propose that increased AGE levels and oxidative stress, although not the only pathway, are significant mediators in the pathogenesis of peri-implantitis. Altering them may potentially be used in combination with other modalities to manage peri-implantitis. PMID:26624598

  18. Accumulation of advanced glycation end products and chronic complications in ESRD treated by dialysis.

    PubMed

    Meerwaldt, Robbert; Zeebregts, Clark J; Navis, Gerjan; Hillebrands, Jan-Luuk; Lefrandt, Joop D; Smit, Andries J

    2009-01-01

    Cardiovascular and connective tissue disorders are very common in patients with end-stage renal disease (ESRD), and the accumulation of advanced glycation end products (AGEs) is significantly increased in these patients. Accumulation of AGEs is believed to have a role in tissue protein aging and the pathogenesis of such age-related diseases as diabetes and ESRD. AGEs accumulate in patients with ESRD as a result of nonenzymatic glycation, oxidative stress, and diminished clearance of AGE precursors. Some AGEs show characteristic brown pigmentation and fluorescence, form protein-protein cross-links, and may ligate with AGE-specific receptors, inducing oxidative stress and cytokine production. This review focuses on the clinical relevance of AGE accumulation in patients with ESRD treated by dialysis for the development of long-term complications. The formation and accumulation of AGEs in patients with ESRD are discussed, as well as the relationship between AGE accumulation and such major complications of ESRD as cardiovascular and connective tissue disorders. PMID:19036487

  19. 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

    2015-11-12

    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.

  20. 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

  1. Inhibitory effect of leonurine on the formation of advanced glycation end products.

    PubMed

    Huang, Lianqi; Yang, Xin; Peng, Anlin; Wang, Hui; Lei, Xiang; Zheng, Ling; Huang, Kun

    2015-02-01

    Long-term hyperglycemia is a typical symptom of diabetes mellitus (DM) which can cause a high level of protein glycation and lead to the formation of advanced glycation end products (AGEs). The accumulation of AGEs in turn deteriorates DM and its complications. Insulin, the only hormone that directly decreases blood sugar in vivo, is vulnerable to glycation which causes the loss of its biological activity. In this study, we used a porcine insulin (PI)-methylglyoxal (MGO) model to investigate the inhibitory effect of leonurine (LN), a natural alkaloid extracted from Herba leonuri, on AGE formation. Assays including AGE-specific fluorescence, and fructosamine level and carbonyl group content determination showed that LN can dose-dependently suppress PI glycation. A significantly decreased cross-linking level on the glycated PI was also proven by SDS-PAGE electrophoresis. A further liquid chromatography-mass spectrometry study suggested that LN may inhibit PI glycation through trapping MGO and keeping it from reacting with PI. Our results thus indicate that LN is a promising anti-glycation agent for the prevention of diabetes and its complications via inhibiting AGE formation.

  2. 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

  3. Receptor for advanced glycation end products (RAGE): a novel therapeutic target for diabetic vascular complication.

    PubMed

    Yamagishi, Sho-ichi; Nakamura, Kazuo; Matsui, Takanori; Noda, Yoshihiro; Imaizumi, Tsutomu

    2008-01-01

    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. Although several hyperglycemia-elicited metabolic and hemodynamic derangements have been implicated in the pathogenesis of diabetic vascular complication, the process of formation and accumulation of advanced glycation end products (AGEs) and their mode of action are most compatible with the theory 'hyperglycemic memory'. Further, there is a growing body of evidence that AGEs and their receptor (RAGE) axis is involved in the pathogenesis of diabetic vascular complication. Indeed, the engagement of RAGE with AGEs is shown to elicit oxidative stress generation and subsequently evoke inflammatory responses in various types of cells, thus playing an important role in the development and progression of diabetic micro- and macroangiopathy. These observations suggest that down-regulation of RAGE expression or blockade of the RAGE downstream signaling may be a promising target for therapeutic intervention in diabetic vascular complication. In this review, we discuss several types of agents that could potentially inhibit RAGE expression or its downstream pathways and their therapeutic implications in diabetic vascular complication. PMID:18289075

  4. Hydrogen Sulfide Prevents Advanced Glycation End-Products Induced Activation of the Epithelial Sodium Channel

    PubMed Central

    Wang, Qiushi; Song, Binlin; Jiang, Shuai; Liang, Chen; Chen, Xiao; Shi, Jing; Li, Xinyuan; Sun, Yingying; Wu, Mingming; Zhao, Dan; Zhang, Zhi-Ren; Ma, He-Ping

    2015-01-01

    Advanced glycation end-products (AGEs) are complex and heterogeneous compounds implicated in diabetes. Sodium reabsorption through the epithelial sodium channel (ENaC) at the distal nephron plays an important role in diabetic hypertension. Here, we report that H2S antagonizes AGEs-induced ENaC activation in A6 cells. ENaC open probability (PO) in A6 cells was significantly increased by exogenous AGEs and that this AGEs-induced ENaC activity was abolished by NaHS (a donor of H2S) and TEMPOL. Incubating A6 cells with the catalase inhibitor 3-aminotriazole (3-AT) mimicked the effects of AGEs on ENaC activity, but did not induce any additive effect. We found that the expression levels of catalase were significantly reduced by AGEs and both AGEs and 3-AT facilitated ROS uptake in A6 cells, which were significantly inhibited by NaHS. The specific PTEN and PI3K inhibitors, BPV(pic) and LY294002, influence ENaC activity in AGEs-pretreated A6 cells. Moreover, after removal of AGEs from AGEs-pretreated A6 cells for 72 hours, ENaC PO remained at a high level, suggesting that an AGEs-related “metabolic memory” may be involved in sodium homeostasis. Our data, for the first time, show that H2S prevents AGEs-induced ENaC activation by targeting the ROS/PI3K/PTEN pathway. PMID:26078825

  5. Accumulation of advanced glycation end products and chronic complications in ESRD treated by dialysis.

    PubMed

    Meerwaldt, Robbert; Zeebregts, Clark J; Navis, Gerjan; Hillebrands, Jan-Luuk; Lefrandt, Joop D; Smit, Andries J

    2009-01-01

    Cardiovascular and connective tissue disorders are very common in patients with end-stage renal disease (ESRD), and the accumulation of advanced glycation end products (AGEs) is significantly increased in these patients. Accumulation of AGEs is believed to have a role in tissue protein aging and the pathogenesis of such age-related diseases as diabetes and ESRD. AGEs accumulate in patients with ESRD as a result of nonenzymatic glycation, oxidative stress, and diminished clearance of AGE precursors. Some AGEs show characteristic brown pigmentation and fluorescence, form protein-protein cross-links, and may ligate with AGE-specific receptors, inducing oxidative stress and cytokine production. This review focuses on the clinical relevance of AGE accumulation in patients with ESRD treated by dialysis for the development of long-term complications. The formation and accumulation of AGEs in patients with ESRD are discussed, as well as the relationship between AGE accumulation and such major complications of ESRD as cardiovascular and connective tissue disorders.

  6. 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

  7. Influence of dietary advanced glycation end products on wound healing in nondiabetic mice.

    PubMed

    Zhu, Yuanchang; Lan, Feifei; Wei, Jiange; Chong, Boonhor; Chen, Pakho; Huynh, Longquan; Wong, Nganwa; Liu, Yu

    2011-01-01

    The present study was to determine advanced glycation end products (AGEs) in foods from different processes, and the influence of dietary AGEs on wound healing in nondiabetic mice. AGEs mixtures were extracted from local fast foods and foods prepared in lab. A BSA-AGEs mixture made by incubating glucose with bovine serum albumin (BSA) was used as a positive control. Burns were made on the skin of mice. The results showed that foods processed by high temperatures generated higher dietary AGEs. Nonwounded mice showed no observable adverse response to high dietary AGEs. However, high dietary AGEs caused severe inflammatory responses in wounded mice. The plasma level of high mobility group box 1 (HMGB1) and its mRNA in white blood cells were found to be significantly higher in the wounded mice fed with high dietary AGEs than others. We conclude that dietary AGEs worsen inflammation and delay wound healing in nondiabetic burned mice, which might be mediated by HMGB1. PMID:21535730

  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. [Advanced glycation and lipoxidation end products--amplifiers of inflammation: the role of food].

    PubMed

    Gil, A; Bengmark, S

    2007-01-01

    Chronic diseases (CD) represent the main cause of mortality in developed countries. The increase in the prevalence of of CD is associated with changes in lifestyle habits, including those related to the consumption of processed foodstuffs. In these foods advanced glycation end products (AGE) and advanced lipoperoxydation products (ALE) are formed as a consequence of the reactivity of proteins, carbohydrates, lipid and other components. The aim of the present review is to offer a perspective of how AGE and ALE affect the physiology and development of CD. Continous intake of AGE and ALE contributes to the exccesive accumulation of these products into body tissues, which in turn negatively influence the innate immune system, inflammatory responses, and resistance to diseases. This is achieved by direct interaction of AGE and ALE with specific cell AGE receptors (RAGE) that have a key role as master switches regulating the development of CD. Long-life molecules, namely collagen and myelin, and low-turnover tissues, e.g. connective, bone and neural tissues, are the main targets of AGE and ALE. In these tissues, AGE and ALE lead to the synthesis of insoluble compounds that severely alter cellular functionality. It has been reported associations of AGE and ALE with allergic and autoimmune diseases, Alzheimer disease and other degenerative disorders, catarats, atherosclerosis, cancer, and diabetes mellitus type 2, as well as a number of endocrine, gastrointestinal, skeleton-muscle, and urogenital alterations. Controlling all those pathologies would need further dietary recommendations aiming to limit the intake of processed foods rich in AGE and ALE, as well as to reduce the formation of those products by improving technological processes applicable to foods.

  10. Ciprofloxacin inhibits advanced glycation end products-induced adhesion molecule expression on human monocytes

    PubMed Central

    Mori, S; Takahashi, HK; Liu, K; Wake, H; Zhang, J; Liu, R; Yoshino, T; Nishibori, M

    2010-01-01

    BACKGROUND AND PURPOSE Advanced glycation end products (AGEs) subtypes, proteins or lipids that become glycated after exposure to sugars, can induce complications in diabetes. Among the various AGE subtypes, glyceraldehyde-derived AGE (AGE-2) and glycolaldehyde-derived AGE (AGE-3) are involved in inflammation in diabetic patients; monocytes are activated by these AGEs. Ciprofloxacin (CIP), a fluorinated 4-quinolone, is often used clinically to treat infections associated with diabetis due to its antibacterial properties. It also modulates immune responses in human peripheral blood mononuclear cells (PBMC) therefore we investigated the involvement of AGEs in these effects. EXPERIMENTAL APPROACH Expression of intercellular adhesion molecule (ICAM)-1, B7.1, B7.2 and CD40 was examined by flow cytometry. The production of tumour necrosis factor (TNF)-α, interferon (IFN)-γ, prostaglandin E2 (PGE2) and cAMP were determined by enzyme-linked immunosorbent assay. Cyclooxygenase (COX)-2 expression was determined by Western blot analysis. Lymphocyte proliferation was determined by [3H]-thymidine uptake. KEY RESULTS CIP induced PGE2 production in monocytes, irrespective of the presence of AGE-2 and AGE-3, by enhancing COX-2 expression; this led to an elevation of intracellular cAMP in monocytes. Non-selective and selective COX-2 inhibitors, indomethacin and NS398, inhibited CIP-induced PGE2 and cAMP production. In addition, CIP inhibited AGE-2- and AGE-3-induced expressions of ICAM-1, B7.1, B7.2 and CD40 in monocytes, the production of TNF-α and IFN-γ and lymphocyte proliferation in PBMC. Indomethacin, NS398 and a protein kinase A inhibitor, H89, inhibited the actions of CIP. CONCLUSIONS AND IMPLICATIONS CIP exerts immunomodulatory activity via PGE2, implying therapeutic potential of CIP for the treatment of AGE-2- and AGE-3-induced inflammatory responses. PMID:20718752

  11. 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

  12. 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

  13. DNA aptamer raised against advanced glycation end products inhibits melanoma growth in nude mice.

    PubMed

    Ojima, Ayako; Matsui, Takanori; Maeda, Sayaka; Takeuchi, Masayoshi; Inoue, Hiroyoshi; Higashimoto, Yuichiro; Yamagishi, Sho-ichi

    2014-04-01

    Epidemiological studies have suggested that diabetes is associated with an increased risk of cancer. However, the underlying molecular mechanism remains unclear. We investigated here whether DNA aptamer directed against advanced glycation end products (AGE-aptamer) inhibited melanoma growth in nude mice. G361 melanoma cells were injected intradermally into the upper flank of athymic nude mice. Mice received continuous intraperitoneal infusion (0.136 μg/day) of either AGE-aptamer (n=9) or Control-aptamer (n=8) by an osmotic mini pump. Tumor volume was measured at 4-day interval, and G361 melanoma was excised at day 43 after the aptamer treatment. We further examined the effects of AGE-aptamer on proliferation of AGE-exposed endothelial cells and G361 cells. AGE-aptamer significantly inhibited the in vivo-tumor growth of G361 melanoma. Immunohistochemical and western blotting analyses of G361 melanoma revealed that AGE-aptamer decreased expression levels of proliferating nuclear antigen, CD31 and Mac-3, markers of endothelial cells and macrophages, respectively. AGE-aptamer significantly decreased the number of tumor-associated vessels. AGE, receptor for AGE (RAGE) and vascular endothelial growth factor levels were also reduced in AGE-aptamer-treated G361 melanoma. AGE-aptamer inhibited the AGE-induced proliferation and tube formation of endothelial cells as well as the growth of G361 cells in vitro. The present findings suggest that AGE-aptamer could inhibit the AGE-RAGE axis in G361 melanoma and resultantly suppress the tumor growth in nude mice by blocking the angiogenesis. AGE-aptamer might be a novel therapeutic strategy for preventing the progression of malignant melanoma in diabetes.

  14. Dietary advanced glycation end-products aggravate non-alcoholic fatty liver disease

    PubMed Central

    Leung, Christopher; Herath, Chandana B; Jia, Zhiyuan; Andrikopoulos, Sof; Brown, Bronwyn E; Davies, Michael J; Rivera, Leni R; Furness, John B; Forbes, Josephine M; Angus, Peter W

    2016-01-01

    AIM To determine if manipulation of dietary advanced glycation end product (AGE), intake affects non-alcoholic fatty liver disease (NAFLD) progression and whether these effects are mediated via RAGE. METHODS Male C57Bl6 mice were fed a high fat, high fructose, high cholesterol (HFHC) diet for 33 wk and compared with animals on normal chow. A third group were given a HFHC diet that was high in AGEs. Another group was given a HFHC diet that was marinated in vinegar to prevent the formation of AGEs. In a second experiment, RAGE KO animals were fed a HFHC diet or a high AGE HFHC diet and compared with wildtype controls. Hepatic biochemistry, histology, picrosirius red morphometry and hepatic mRNA were determined. RESULTS Long-term consumption of the HFHC diet generated significant steatohepatitis and fibrosis after 33 wk. In this model, hepatic 4-hydroxynonenal content (a marker of chronic oxidative stress), hepatocyte ballooning, picrosirius red staining, α-smooth muscle actin and collagen type 1A gene expression were all significantly increased. Increasing the AGE content of the HFHC diet by baking further increased these markers of liver damage, but this was abrogated by pre-marination in acetic acid. In response to the HFHC diet, RAGE-/- animals developed NASH of similar severity to RAGE+/+ animals but were protected from the additional harmful effects of the high AGE containing diet. Studies in isolated Kupffer cells showed that AGEs increase cell proliferation and oxidative stress, providing a likely mechanism through which these compounds contribute to liver injury. CONCLUSION In the HFHC model of NAFLD, manipulation of dietary AGEs modulates liver injury, inflammation, and liver fibrosis via a RAGE dependent pathway. This suggests that pharmacological and dietary strategies targeting the AGE/RAGE pathway could slow the progression of NAFLD. PMID:27672297

  15. Impairment of human keratinocyte mobility and proliferation by advanced glycation end products-modified BSA.

    PubMed

    Zhu, Ping; Yang, Chuan; Chen, Li-Hong; Ren, Meng; Lao, Guo-Juan; Yan, Li

    2011-07-01

    The migration and proliferation of keratinocytes is critical to wound re-epithelialization and defects in this function are associated with the clinical phenomenon of chronic non-healing wounds. Advanced glycation end products (AGEs) occur through non-enzymatic glycation of long-lived proteins in diabetes and play important roles in diabetic complications. However, specific roles for AGEs in keratinocyte migration and proliferation, and the underlying molecular mechanisms, have not been fully established. The aim of the current study was to elucidate the interaction between AGE-modified bovine serum albumin (AGE-BSA) and keratinocytes. As a result, we found that AGE-BSA had no effect on the viability of keratinocytes for up to 48 h of incubation with 50 μg/ml of AGE-BSA. AGE-BSA (but not non-glycated BSA) exerted a concentration-dependent suppression of keratinocyte migration at a range of concentrations. The expression of matrix metalloproteinase-9 (MMP-9) was significantly up-regulated in keratinocytes incubated with increasing AGE-BSA, but tissue inhibitor of metalloproteinases-1 (TIMP-1) expression was down-regulated. AGE-BSA also profoundly depressed phospho-focal adhesion kinase-Tyr397 (p-FAK) and α2β1 integrin expression, while total-FAK expression levels remained constant, in keratinocytes. The proliferative capacity of keratinocytes was diminished after 72 h AGE-BSA incubation. Taken together, these findings suggested that in the presence of AGE-BSA, keratinocytes lose their migratory and proliferation abilities. These data also indicated that, in the context of the chronic hyperglycemia in diabetes, the effects of AGE-BSA on keratinocyte migration might be mediated through MMP-9/TIMP-1, p-FAK and α2β1 integrin.

  16. 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

  17. 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.

  18. Rifampicin reduces advanced glycation end products and activates DAF-16 to increase lifespan in Caenorhabditis elegans.

    PubMed

    Golegaonkar, Sandeep; Tabrez, Syed S; Pandit, Awadhesh; Sethurathinam, Shalini; Jagadeeshaprasad, Mashanipalya G; Bansode, Sneha; Sampathkumar, Srinivasa-Gopalan; Kulkarni, Mahesh J; Mukhopadhyay, Arnab

    2015-06-01

    Advanced glycation end products (AGEs) are formed when glucose reacts nonenzymatically with proteins; these modifications are implicated in aging and pathogenesis of many age-related diseases including type II diabetes, atherosclerosis, and neurodegenerative disorders. Thus, pharmaceutical interventions that can reduce AGEs may delay age-onset diseases and extend lifespan. Using LC-MS(E), we show that rifampicin (RIF) reduces glycation of important cellular proteins in vivo and consequently increases lifespan in Caenorhabditis elegans by up to 60%. RIF analog rifamycin SV (RSV) possesses similar properties, while rifaximin (RMN) lacks antiglycation activity and therefore fails to affect lifespan positively. The efficacy of RIF and RSV as potent antiglycating agents may be attributed to the presence of a p-dihydroxyl moiety that can potentially undergo spontaneous oxidation to yield highly reactive p-quinone structures, a feature absent in RMN. We also show that supplementing rifampicin late in adulthood is sufficient to increase lifespan. For its effect on longevity, rifampicin requires DAF-18 (nematode PTEN) as well as JNK-1 and activates DAF-16, the FOXO homolog. Interestingly, the drug treatment modulates transcription of a different subset of DAF-16 target genes, those not controlled by the conserved Insulin-IGF-1-like signaling pathway. RIF failed to increase the lifespan of daf-16 null mutant despite reducing glycation, showing thereby that DAF-16 may not directly affect AGE formation. Together, our data suggest that the dual ability to reduce glycation in vivo and activate prolongevity processes through DAF-16 makes RIF and RSV effective lifespan-extending interventions. PMID:25720500

  19. Rifampicin reduces advanced glycation end products and activates DAF-16 to increase lifespan in Caenorhabditis elegans

    PubMed Central

    Golegaonkar, Sandeep; Tabrez, Syed S; Pandit, Awadhesh; Sethurathinam, Shalini; Jagadeeshaprasad, Mashanipalya G; Bansode, Sneha; Sampathkumar, Srinivasa-Gopalan; Kulkarni, Mahesh J; Mukhopadhyay, Arnab

    2015-01-01

    Advanced glycation end products (AGEs) are formed when glucose reacts nonenzymatically with proteins; these modifications are implicated in aging and pathogenesis of many age-related diseases including type II diabetes, atherosclerosis, and neurodegenerative disorders. Thus, pharmaceutical interventions that can reduce AGEs may delay age-onset diseases and extend lifespan. Using LC-MSE, we show that rifampicin (RIF) reduces glycation of important cellular proteins in vivo and consequently increases lifespan in Caenorhabditis elegans by up to 60%. RIF analog rifamycin SV (RSV) possesses similar properties, while rifaximin (RMN) lacks antiglycation activity and therefore fails to affect lifespan positively. The efficacy of RIF and RSV as potent antiglycating agents may be attributed to the presence of a p-dihydroxyl moiety that can potentially undergo spontaneous oxidation to yield highly reactive p-quinone structures, a feature absent in RMN. We also show that supplementing rifampicin late in adulthood is sufficient to increase lifespan. For its effect on longevity, rifampicin requires DAF-18 (nematode PTEN) as well as JNK-1 and activates DAF-16, the FOXO homolog. Interestingly, the drug treatment modulates transcription of a different subset of DAF-16 target genes, those not controlled by the conserved Insulin-IGF-1-like signaling pathway. RIF failed to increase the lifespan of daf-16 null mutant despite reducing glycation, showing thereby that DAF-16 may not directly affect AGE formation. Together, our data suggest that the dual ability to reduce glycation in vivo and activate prolongevity processes through DAF-16 makes RIF and RSV effective lifespan-extending interventions. PMID:25720500

  20. Advanced glycation end product associated skin autofluorescence: a mirror of vascular function?

    PubMed

    Hofmann, Britt; Adam, Anne-Catrin; Jacobs, Kathleen; Riemer, Marcus; Erbs, Christian; Bushnaq, Hasan; Simm, Andreas; Silber, Rolf-Edgar; Santos, Alexander Navarrete

    2013-01-01

    Advanced glycation end products (AGEs) seem to be involved in aging as well as in the development of cardiovascular diseases. During aging, AGEs accumulate in extracellular matrix proteins like collagen and contribute to vessel stiffness. Whether non-invasive measurement of AGE accumulation in the skin may reflect vessel function and vessel protein modification is unknown. Herein we set out to analyze the AGE-modifications in the collagens extracted from residual bypass graft material, the skin autofluorescence reflecting the accumulation of AGEs in the body as well as the pulse wave velocity reflecting vessel stiffness. Collagen types I and III (pepsin digestible collagen fraction) were isolated from the veins of 52 patients by proteolysis. The residual collagen fraction was further extracted by collagenase digestion. Collagen was quantified by hydroxyproline assay and AGEs by the AGE intrinsic fluorescence. Skin autofluorescence was measured with an autofluorescence reader; pulse wave velocity with the VICORDER. The collagen AGE autofluorescence in patient vein graft material increased with patient age. The pepsin digestible collagen fraction was significantly less modified in comparison to the collagenase digestible fraction. Decreasing amounts of extracted collagenase digestible collagen correspond with increasing AGE autofluorescence. Skin autofluorescence and vessel stiffness were significantly linked to the AGE autofluorescence of the collagenase digestible collagen fraction from graft material. In conclusion we have found that skin autofluorescence and pulse wave velocity as non-invasive parameters significantly correlate with the AGE contained in graft material and therefore are strong predictors of vessel AGE modifications in patients with coronary heart disease. Whether the analysis of the skin autofluorescence leads to an improvement of the risk stratification in patients suffering from cardiovascular disease has to be further tested.

  1. Accumulation of advanced glycation end products, measured as skin autofluorescence, in renal disease.

    PubMed

    Hartog, Jasper W L; de Vries, Aiko P J; Lutgers, Helen L; Meerwaldt, Robbert; Huisman, Roel M; van Son, Willem J; de Jong, Paul E; Smit, Andries J

    2005-06-01

    Advanced glycation end products (AGEs) accumulate during renal failure and dialysis. Kidney transplantation is thought to reverse this accumulation by restoring renal function. Using a noninvasive and validated autofluorescence reader, we evaluated AGE levels in 285 transplant recipients (mean age, 52 years; range, 41 to 60 years), 32 dialysis patients (mean age, 56 years; range, 43 to 65 years), and 231 normal control subjects (mean age, 51 years; range, 40 to 65 years). Measurements in transplant recipients were performed for a mean of 73 months (range, 32 to 143 months) after transplantation. Dialysis patients were on dialysis therapy for a mean of 42 months (range, 17 to 107 months). Fluorescence was significantly increased in dialysis patients compared with normal control subjects (2.8 vs. 2.0 arbitrary units [a.u.], P < .0001). Although fluorescence levels were significantly decreased in transplant recipients compared with dialysis patients (2.5 vs. 2.8 a.u., P < .0001), fluorescence in transplant recipients was higher than in controls (2.5 vs. 2.0 a.u., P < .0001). In transplant recipients, fluorescence correlated positively with the duration of dialysis prior to transplantation (R = 0.21, P < .0001), and negatively with creatinine clearance (R = -0.34, P < .0001). No correlation was found between time after transplantation and fluorescence in transplant recipients (R = -0.10, P = .10). Fluorescence in dialysis patients was positively correlated with duration of dialysis (R = 0.36, P = .042). Our results, like those of others, suggest that kidney transplantation does not fully correct increased AGE levels found in dialysis patients. The increased AGE levels in kidney transplant recipients cannot be explained by the differences in renal function alone. The availability of a simple, noninvasive method (AGE-Reader) to measure AGE accumulation may be used to monitor AGE accumulation in a clinical setting as well as in a study setting.

  2. Advanced glycation end products measured by skin autofluorescence in a population with central obesity.

    PubMed

    den Engelsen, Corine; van den Donk, Maureen; Gorter, Kees J; Salomé, Philippe L; Rutten, Guy E

    2012-01-01

    Accumulation of advanced glycation end products (AGEs) is enhanced by chronic hyperglycemia and oxidative stress and this process may contribute to the pathogenesis of vascular disease. Skin autofluorescence (AF), a measure of accumulation of AGEs in skin collagen, is associated with vascular disease in patients with diabetes.   Because central obesity enhances oxidative stress people with central obesity might already have increased accumulation of AGEs before diabetes or cardiovascular disease become manifest. To test this hypothesis, we compared the distribution of skin AF and its association with clinical and biochemical parameters in individuals with and without central obesity. Skin AF was measured by a validated AGE Reader in 816 persons with and 431 persons without central obesity, aged 20-70 y. Mean skin AF increased with age and smoking and was higher in centrally obese individuals compared with non-obese individuals (p = 0.001, after adjustment for age and smoking p = 0.13). Mean skin AF in the subgroups without central obesity and without other risk factors (n = 106), central obesity without other risk factors (n = 74) and central obesity with other risk factors (n = 742) was 1.63 ± 0.37, 1.74 ± 0.44 and 1.87 ± 0.43 AU, respectively (p for trend < 0.001, after adjustment for age and smoking p for trend = 0.12). In the group with central obesity age, current smoking, alcohol consumption, waist circumference, creatinine clearance and hs-CRP were independently associated with skin AF (R(2) = 29.4%). Waist circumference hardly contributed to the explained variance. The relationship between waist circumference and skin AF is not as obvious as we hypothesized.

  3. Advanced glycation end products and the progressive course of renal disease.

    PubMed

    Heidland, A; Sebekova, K; Schinzel, R

    2001-10-01

    In experimental and human diabetic nephropathy (DN), it has been shown that advanced glycation end products (AGEs), in particular, carboxymethyl-lysine and pentosidine, accumulate with malondialdehyde in glomerular lesions in relation to disease severity and in the presence of an upregulated receptor for AGE (RAGE) in podocytes. Toxic effects of AGEs result from structural and functional alterations in plasma and extracellular matrix (ECM) proteins, in particular, from cross-linking of proteins and interaction of AGEs with their receptors and/or binding proteins. In mesangial and endothelial cells, the AGE-RAGE interaction caused enhanced formation of oxygen radicals with subsequent activation of nuclear factor-kappaB and release of pro-inflammatory cytokines (interleukin-6, tumor necrosis factor-alpha), growth factors (transforming growth factor-beta1 [TGF-beta1], insulin-like growth factor-1), and adhesion molecules (vascular cell adhesion molecule-1, intercellular adhesion molecule-1). In tubular cells, incubation with AGE albumin was followed by stimulation of the mitogen-activating protein (MAP) kinase pathway and its downstream target, the activating protien-1 (AP-1) complex, TGF-beta1 overexpression, enhanced protein kinase C activity, decreased cell proliferation, and impaired protein degradation rate, in part caused by decreased cathepsin activities. The pathogenic relevance of AGEs was further verified by in vivo experiments in euglycemic rats and mice by the parenteral administration of AGE albumin, leading in the glomeruli to TGF-beta1 overproduction, enhanced gene expression of ECM proteins, and morphological lesions similar to those of DN. Evidence for the pathogenic relevance of AGEs in DN also comes from experimental studies in which the formation and/or action of AGEs was modulated by aminoguanidine, OPB-9195, pyridoxamine, soluble RAGEs, serine protease trypsin, and antioxidants, resulting in improved cell and/or renal function.

  4. 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.

  5. Bone Formation is Affected by Matrix Advanced Glycation End Products (AGEs) In Vivo.

    PubMed

    Yang, Xiao; Mostafa, Ahmed Jenan; Appleford, Mark; Sun, Lian-Wen; Wang, Xiaodu

    2016-10-01

    Advanced glycation end products (AGEs) accumulate in bone extracellular matrix as people age. Although previous evidence shows that the accumulation of AGEs in bone matrix may impose significant effects on bone cells, the effect of matrix AGEs on bone formation in vivo is still poorly understood. To address this issue, this study used a unique rat model with autograft implant to investigate the in vivo response of bone formation to matrix AGEs. Fluorochrome biomarkers were sequentially injected into rats to label the dynamic bone formation in the presence of elevated levels of matrix AGEs. After sacrificing animals, dynamic histomorphometry was performed to determine mineral apposition rate (MAR), mineralized surface per bone surface (MS/BS), and bone formation rate (BFR). Finally, nanoindentation tests were performed to assess mechanical properties of newly formed bone tissues. The results showed that MAR, MS/BS, and BFR were significantly reduced in the vicinity of implant cores with high concentration of matrix AGEs, suggesting that bone formation activities by osteoblasts were suppressed in the presence of elevated matrix AGEs. In addition, MAR and BFR were found to be dependent on the surrounding environment of implant cores (i.e., cortical or trabecular tissues). Moreover, MS/BS and BFR were also dependent on how far the implant cores were away from the growth plate. These observations suggest that the effect of matrix AGEs on bone formation is dependent on the biological milieu around the implants. Finally, nanoindentation test results indicated that the indentation modulus and hardness of newly formed bone tissues were not affected by the presence of elevated matrix AGEs. In summary, high concentration of matrix AGEs may slow down the bone formation process in vivo, while imposing little effects on bone mineralization.

  6. Advanced Glycation End Products and its Soluble Receptors in the Pathogenesis of Thoracic Aortic Aneurysm

    PubMed Central

    Prasad, Kailash; Sarkar, Abdullah; Zafar, Mohammad A.; Shoker, Ahmed; Moselhi, Hamdi EI; Tranquilli, Maryann; Ziganshin, Bulat A.; Elefteriades, John A.

    2016-01-01

    Background Matrix metalloproteinases (MMPs) have been implicated in the pathogenesis of thoracic aortic aneurysms (TAAs). Cytokines [Interleukin (IL)-Iβ, IL-2, IL-6, and TNF-α)] increase the expression of MMP-2 and -3. Advanced glycation end products (AGEs) interact with cell receptors to increase the release of cytokines. Circulating soluble receptors for AGEs (sRAGE) and endogenous secretory RAGE (esRAGE) compete with membrane bound RAGE for binding with AGEs and reduce the production of cytokines. It is hypothesized that low levels of serum sRAGE and esRAGE and high levels of AGEs, AGEs/sRAGE, and AGEs/esRAGE would increase the levels of cytokines that would increase the levels MMPs, thus contributing to the formation of TAAs. Methods The study population was composed of 17 control subjects and 20 patients with TAA. Blood samples were collected for measurement of serum sRAGE, esRAGE, AGEs, cytokines, and MMPs. AGEs, sRAGE, and esRAGE were measured using ELISA kits, whereas the remaining parameters were measured using the Luminex Multi-Analyte system. Results The levels of sRAGE were lower, while the levels of AGEs, AGEs/sRAGE, AGEs/esRAGE, cytokines and MMPs were higher in patients with TAA compared to controls. The levels of sRAGE were inversely correlated with cytokines and MMPs, while AGEs, AGEs/sRAGE and AGEs/esRAGE were positively correlated with cytokines and MMPs. Cytokines were positively correlated with MMPs. Conclusions The data suggest that the AGE-RAGE axis may be involved in the pathogenesis of TAA and that low levels of sRAGE and high levels of AGEs, AGEs/sRAGE, and AGEs/esRAGE are risk factors for TAA. PMID:27766267

  7. 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.

  8. Rifampicin reduces advanced glycation end products and activates DAF-16 to increase lifespan in Caenorhabditis elegans.

    PubMed

    Golegaonkar, Sandeep; Tabrez, Syed S; Pandit, Awadhesh; Sethurathinam, Shalini; Jagadeeshaprasad, Mashanipalya G; Bansode, Sneha; Sampathkumar, Srinivasa-Gopalan; Kulkarni, Mahesh J; Mukhopadhyay, Arnab

    2015-06-01

    Advanced glycation end products (AGEs) are formed when glucose reacts nonenzymatically with proteins; these modifications are implicated in aging and pathogenesis of many age-related diseases including type II diabetes, atherosclerosis, and neurodegenerative disorders. Thus, pharmaceutical interventions that can reduce AGEs may delay age-onset diseases and extend lifespan. Using LC-MS(E), we show that rifampicin (RIF) reduces glycation of important cellular proteins in vivo and consequently increases lifespan in Caenorhabditis elegans by up to 60%. RIF analog rifamycin SV (RSV) possesses similar properties, while rifaximin (RMN) lacks antiglycation activity and therefore fails to affect lifespan positively. The efficacy of RIF and RSV as potent antiglycating agents may be attributed to the presence of a p-dihydroxyl moiety that can potentially undergo spontaneous oxidation to yield highly reactive p-quinone structures, a feature absent in RMN. We also show that supplementing rifampicin late in adulthood is sufficient to increase lifespan. For its effect on longevity, rifampicin requires DAF-18 (nematode PTEN) as well as JNK-1 and activates DAF-16, the FOXO homolog. Interestingly, the drug treatment modulates transcription of a different subset of DAF-16 target genes, those not controlled by the conserved Insulin-IGF-1-like signaling pathway. RIF failed to increase the lifespan of daf-16 null mutant despite reducing glycation, showing thereby that DAF-16 may not directly affect AGE formation. Together, our data suggest that the dual ability to reduce glycation in vivo and activate prolongevity processes through DAF-16 makes RIF and RSV effective lifespan-extending interventions.

  9. Dietary advanced glycation end-products aggravate non-alcoholic fatty liver disease

    PubMed Central

    Leung, Christopher; Herath, Chandana B; Jia, Zhiyuan; Andrikopoulos, Sof; Brown, Bronwyn E; Davies, Michael J; Rivera, Leni R; Furness, John B; Forbes, Josephine M; Angus, Peter W

    2016-01-01

    AIM To determine if manipulation of dietary advanced glycation end product (AGE), intake affects non-alcoholic fatty liver disease (NAFLD) progression and whether these effects are mediated via RAGE. METHODS Male C57Bl6 mice were fed a high fat, high fructose, high cholesterol (HFHC) diet for 33 wk and compared with animals on normal chow. A third group were given a HFHC diet that was high in AGEs. Another group was given a HFHC diet that was marinated in vinegar to prevent the formation of AGEs. In a second experiment, RAGE KO animals were fed a HFHC diet or a high AGE HFHC diet and compared with wildtype controls. Hepatic biochemistry, histology, picrosirius red morphometry and hepatic mRNA were determined. RESULTS Long-term consumption of the HFHC diet generated significant steatohepatitis and fibrosis after 33 wk. In this model, hepatic 4-hydroxynonenal content (a marker of chronic oxidative stress), hepatocyte ballooning, picrosirius red staining, α-smooth muscle actin and collagen type 1A gene expression were all significantly increased. Increasing the AGE content of the HFHC diet by baking further increased these markers of liver damage, but this was abrogated by pre-marination in acetic acid. In response to the HFHC diet, RAGE-/- animals developed NASH of similar severity to RAGE+/+ animals but were protected from the additional harmful effects of the high AGE containing diet. Studies in isolated Kupffer cells showed that AGEs increase cell proliferation and oxidative stress, providing a likely mechanism through which these compounds contribute to liver injury. CONCLUSION In the HFHC model of NAFLD, manipulation of dietary AGEs modulates liver injury, inflammation, and liver fibrosis via a RAGE dependent pathway. This suggests that pharmacological and dietary strategies targeting the AGE/RAGE pathway could slow the progression of NAFLD.

  10. Accumulation of advanced glycation end products, measured as skin autofluorescence, in renal disease.

    PubMed

    Hartog, Jasper W L; de Vries, Aiko P J; Lutgers, Helen L; Meerwaldt, Robbert; Huisman, Roel M; van Son, Willem J; de Jong, Paul E; Smit, Andries J

    2005-06-01

    Advanced glycation end products (AGEs) accumulate during renal failure and dialysis. Kidney transplantation is thought to reverse this accumulation by restoring renal function. Using a noninvasive and validated autofluorescence reader, we evaluated AGE levels in 285 transplant recipients (mean age, 52 years; range, 41 to 60 years), 32 dialysis patients (mean age, 56 years; range, 43 to 65 years), and 231 normal control subjects (mean age, 51 years; range, 40 to 65 years). Measurements in transplant recipients were performed for a mean of 73 months (range, 32 to 143 months) after transplantation. Dialysis patients were on dialysis therapy for a mean of 42 months (range, 17 to 107 months). Fluorescence was significantly increased in dialysis patients compared with normal control subjects (2.8 vs. 2.0 arbitrary units [a.u.], P < .0001). Although fluorescence levels were significantly decreased in transplant recipients compared with dialysis patients (2.5 vs. 2.8 a.u., P < .0001), fluorescence in transplant recipients was higher than in controls (2.5 vs. 2.0 a.u., P < .0001). In transplant recipients, fluorescence correlated positively with the duration of dialysis prior to transplantation (R = 0.21, P < .0001), and negatively with creatinine clearance (R = -0.34, P < .0001). No correlation was found between time after transplantation and fluorescence in transplant recipients (R = -0.10, P = .10). Fluorescence in dialysis patients was positively correlated with duration of dialysis (R = 0.36, P = .042). Our results, like those of others, suggest that kidney transplantation does not fully correct increased AGE levels found in dialysis patients. The increased AGE levels in kidney transplant recipients cannot be explained by the differences in renal function alone. The availability of a simple, noninvasive method (AGE-Reader) to measure AGE accumulation may be used to monitor AGE accumulation in a clinical setting as well as in a study setting. PMID:16037252

  11. Advanced glycation end products measured by skin autofluorescence in a population with central obesity.

    PubMed

    den Engelsen, Corine; van den Donk, Maureen; Gorter, Kees J; Salomé, Philippe L; Rutten, Guy E

    2012-01-01

    Accumulation of advanced glycation end products (AGEs) is enhanced by chronic hyperglycemia and oxidative stress and this process may contribute to the pathogenesis of vascular disease. Skin autofluorescence (AF), a measure of accumulation of AGEs in skin collagen, is associated with vascular disease in patients with diabetes.   Because central obesity enhances oxidative stress people with central obesity might already have increased accumulation of AGEs before diabetes or cardiovascular disease become manifest. To test this hypothesis, we compared the distribution of skin AF and its association with clinical and biochemical parameters in individuals with and without central obesity. Skin AF was measured by a validated AGE Reader in 816 persons with and 431 persons without central obesity, aged 20-70 y. Mean skin AF increased with age and smoking and was higher in centrally obese individuals compared with non-obese individuals (p = 0.001, after adjustment for age and smoking p = 0.13). Mean skin AF in the subgroups without central obesity and without other risk factors (n = 106), central obesity without other risk factors (n = 74) and central obesity with other risk factors (n = 742) was 1.63 ± 0.37, 1.74 ± 0.44 and 1.87 ± 0.43 AU, respectively (p for trend < 0.001, after adjustment for age and smoking p for trend = 0.12). In the group with central obesity age, current smoking, alcohol consumption, waist circumference, creatinine clearance and hs-CRP were independently associated with skin AF (R(2) = 29.4%). Waist circumference hardly contributed to the explained variance. The relationship between waist circumference and skin AF is not as obvious as we hypothesized. PMID:22870350

  12. Advanced glycation end product associated skin autofluorescence: a mirror of vascular function?

    PubMed

    Hofmann, Britt; Adam, Anne-Catrin; Jacobs, Kathleen; Riemer, Marcus; Erbs, Christian; Bushnaq, Hasan; Simm, Andreas; Silber, Rolf-Edgar; Santos, Alexander Navarrete

    2013-01-01

    Advanced glycation end products (AGEs) seem to be involved in aging as well as in the development of cardiovascular diseases. During aging, AGEs accumulate in extracellular matrix proteins like collagen and contribute to vessel stiffness. Whether non-invasive measurement of AGE accumulation in the skin may reflect vessel function and vessel protein modification is unknown. Herein we set out to analyze the AGE-modifications in the collagens extracted from residual bypass graft material, the skin autofluorescence reflecting the accumulation of AGEs in the body as well as the pulse wave velocity reflecting vessel stiffness. Collagen types I and III (pepsin digestible collagen fraction) were isolated from the veins of 52 patients by proteolysis. The residual collagen fraction was further extracted by collagenase digestion. Collagen was quantified by hydroxyproline assay and AGEs by the AGE intrinsic fluorescence. Skin autofluorescence was measured with an autofluorescence reader; pulse wave velocity with the VICORDER. The collagen AGE autofluorescence in patient vein graft material increased with patient age. The pepsin digestible collagen fraction was significantly less modified in comparison to the collagenase digestible fraction. Decreasing amounts of extracted collagenase digestible collagen correspond with increasing AGE autofluorescence. Skin autofluorescence and vessel stiffness were significantly linked to the AGE autofluorescence of the collagenase digestible collagen fraction from graft material. In conclusion we have found that skin autofluorescence and pulse wave velocity as non-invasive parameters significantly correlate with the AGE contained in graft material and therefore are strong predictors of vessel AGE modifications in patients with coronary heart disease. Whether the analysis of the skin autofluorescence leads to an improvement of the risk stratification in patients suffering from cardiovascular disease has to be further tested. PMID:22588061

  13. Emphysema requires the receptor for advanced glycation end-products triggering on structural cells.

    PubMed

    Waseda, Koichi; Miyahara, Nobuaki; Taniguchi, Akihiko; Kurimoto, Etsuko; Ikeda, Genyo; Koga, Hikari; Fujii, Utako; Yamamoto, Yasuhiko; Gelfand, Erwin W; Yamamoto, Hiroshi; Tanimoto, Mitsune; Kanehiro, Arihiko

    2015-04-01

    Pulmonary emphysema is characterized by persistent inflammation and progressive alveolar destruction. The receptor for advanced glycation end-products (RAGE) is a multiligand cell surface receptor reported to be involved in the process of acute alveolar epithelial cell injury. However, studies that address the role of RAGE in pulmonary emphysema are inconclusive. We investigated the role of RAGE in the development of elastase-induced pulmonary inflammation and emphysema in mice. RAGE-sufficient (RAGE(+/+)) mice and RAGE-deficient (RAGE(-/-)) mice were treated with intratracheal elastase on Day 0. Airway inflammation, static lung compliance, lung histology, and the levels of neutrophil-related chemokine and proinflammatory cytokines in bronchoalveolar lavage fluid were determined on Days 4 and 21. Neutrophilia in bronchoalveolar lavage fluid, seen in elastase-treated RAGE(+/+) mice, was reduced in elastase-treated RAGE(-/-) mice on Day 4, and was associated with decreased levels of keratinocyte chemoattractant, macrophage inflammatory protein-2, and IL-1β. Static lung compliance values and emphysematous changes in the lung tissue were decreased in RAGE(-/-) mice compared with RAGE(+/+) mice on Day 21 after elastase treatment. Experiments using irradiated, bone marrow-chimeric mice showed that the mice expressing RAGE on radioresistant structural cells, but not hematopoietic cells, developed elastase-induced neutrophilia and emphysematous change in the lung. In contrast, mice expressing RAGE on hematopoietic cells, but not radioresistant structural cells, showed reduced neutrophilia and emphysematous change in the lung. These data identify the importance of RAGE expressed on lung structural cells in the development of elastase-induced pulmonary inflammation and emphysema. Thus, RAGE represents a novel therapeutic target for preventing pulmonary emphysema.

  14. 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.

  15. 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

  16. 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

  17. Ex vivo detection of histone H1 modified with advanced glycation end products.

    PubMed

    Pashikanti, Srinath; Boissonneault, Gilbert A; Cervantes-Laurean, Daniel

    2011-05-15

    A number of oxidative stress agents cause DNA and protein damage, which may compromise genomic integrity. Whereas oxidant-induced DNA damage has been extensively studied, much less is known concerning the occurrence and fate of nuclear protein damage, particularly of proteins involved in the regulation and maintenance of chromatin structure. Protein damage may be caused by the formation of reactive carbonyl species such as glyoxal, which forms after lipid peroxide degradation. It may also result from degradation of early protein glycation adducts and from methylglyoxal, formed in the process of glycolytic intermediate degradation. Major adducts indicative of protein damage include the advanced glycation end product (AGE) carboxymethyllysine (CML) and argpyrimidine protein adducts. Thus, the formation of CML and argpyrimidine protein adducts represents potential biomarkers for nuclear protein damage deriving from a variety of sources. The purpose of this study was to identify and quantify AGE adducts formed in vivo in a nuclear protein, specifically histone H1, using CML and argpyrimidine as biomarkers. Histone H1 was isolated from calf thymus collected immediately after slaughter under conditions designed to minimize AGE formation before isolation. Using antibodies directed against oxidative protein adducts, we identified CML, argpyrimidine, and protein crosslinks present in the freshly isolated histone H1. Detailed mass spectroscopy analysis of histone H1 revealed the presence of two specific lysine residues modified by CML adducts. Our results strongly suggest that glycation of important nuclear protein targets such as histone H1 occurs in vivo and that these oxidative changes may alter chromatin structure, ultimately contributing to chronic changes associated with aging and diseases such as diabetes. PMID:21315148

  18. 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

  19. Bone Aging by Advanced Glycation End Products: A Multiscale Mechanical Analysis.

    PubMed

    Ganeko, K; Masaki, C; Shibata, Y; Mukaibo, T; Kondo, Y; Nakamoto, T; Miyazaki, T; Hosokawa, R

    2015-12-01

    The quality and quantity of mandibular bone are essential prerequisites for osseointegrated implants. Only the Hounsfield unit on preoperative computed tomography is currently used as a clinical index. Nevertheless, a considerable mismatch occurs between bone quality and the Hounsfield unit. Loss of bone toughness during aging has been accepted based on empirical evidence, but this concept is unlikely evidence based at the level of mechanical properties. Nonenzymatic bone matrix cross-links associated with advanced glycation end products predominate as a consequence of aging. Thus, loss of tissue integrity could diminish the bone toughening mechanism. Here, we demonstrate an impaired bone toughening mechanism caused by mimicking aging in rabbits on a methionine-rich diet, which enabled an enhanced nonenzymatically cross-linked bone matrix. A 3-point bending test revealed a greater reduction in femoral fracture resistance in rabbits on a methionine-rich diet, despite higher maximum and normalized breaking forces (287.3 N and 88.1%, respectively), than in rabbits on a normal diet (262.2 N and 79.7%, respectively). In situ nanoindentation on mandibular cortical bone obtained from rabbits on a methionine-rich diet did not enable strain rate-dependent stiffening and consequent large-dimensional recovery during rapid loading following constant displacement after a rapid-load indentation test as compared with those in rabbits on a normal diet. Such nanoscale structure-function relationships dictate resistance to cracking propagation at the material level and allow for the overall bone toughening mechanism to operate under large external stressors. The strain-dependent stiffening was likely associated with strain-energy transfer to the superior cross-linked bone matrix network of the normal diet, while the reduction in the enzymatically cross-linked matrix in bone samples from rabbits on a methionine-rich diet likely diminished the intrinsic bone toughening mechanism. The

  20. The Receptor for Advanced Glycation End Products (RAGE) Is Associated with Persistent Atrial Fibrillation

    PubMed Central

    Lancefield, Terase F.; Patel, Sheila K.; Freeman, Melanie; Velkoska, Elena; Wai, Bryan; Srivastava, Piyush M.; Horrigan, Mark; Farouque, Omar; Burrell, Louise M.

    2016-01-01

    Objective Upregulation of the receptor for advanced glycation end products (RAGE) has been proposed as a pathophysiological mechanism underlying the development of atrial fibrillation (AF). We sought to investigate if soluble RAGE levels are associated with AF in Caucasian patients. Methods Patients (n = 587) were prospectively recruited and serum levels of soluble RAGE (sRAGE) and endogenous secretory RAGE (esRAGE) measured. The patients included 527 with sinus rhythm, 32 with persistent AF (duration >7 days, n = 32) and 28 with paroxysmal AF (duration <7 days, n = 28). Results Patients with AF were older and had a greater prevalence of heart failure than patients in sinus rhythm. Circulating RAGE levels were higher in patients with persistent AF [median sRAGE 1190 (724–2041) pg/ml and median esRAGE 452 (288–932) pg/ml] compared with paroxysmal AF [sRAGE 799 (583–1033) pg/ml and esRAGE 279 (201–433) pg/ml, p ≤ 0.01] or sinus rhythm [sRAGE 782 (576–1039) pg/ml and esRAGE 289 (192–412) pg/ml, p < 0.001]. In multivariable logistic regression analysis, independent predictors of persistent AF were age, heart failure, sRAGE [odds ratio 1.1 per 100 pg/ml, 95% confidence interval (CI) 1.0–1.1, p = 0.001] and esRAGE [odds ratio 1.3 per 100 pg/ml, 95% CI 1.1–1.4, p < 0.001]. Heart failure and age were the only independent predictors of paroxysmal AF. In AF patients, sRAGE [odds ratio 1.1 per 100 pg/ml, 95% CI 1.1–1.2, p = 0.007] and esRAGE [odds ratio 1.3 per 100 pg/ml, 95% CI 1.0–1.5, p = 0.017] independently predicted persistent compared with paroxysmal AF. Conclusions Soluble RAGE is elevated in Caucasian patients with AF, and both sRAGE and esRAGE predict the presence of persistent AF. PMID:27627677

  1. Drugs of abuse that mediate advanced glycation end product formation: a chemical link to disease pathology.

    PubMed

    Treweek, Jennifer B; Dickerson, Tobin J; Janda, Kim D

    2009-05-19

    Nicotine and methamphetamine are frequently abused in modern society, despite the increasing evidence of their addictive, neuropharmacological, and toxic effects. Tobacco, the most widely abused substance, is the leading cause of preventable death in the United States, killing nearly half a million Americans annually. A methamphetamine epidemic has also spread during the past decade; severe neurotoxicity and addictiveness contribute to the drug's notoriety. Although the majority of research on these two drugs is of pharmacological and neurobiological motivation, further study of these molecules from a chemical perspective may provide novel mechanistic insight into either their addictive potential or their pathological effects. For example, nicotine and methamphetamine share a common structural feature, a secondary amine, suggesting that these molecules could possess similar (or analogous) in vivo reactivity. Discoveries concerning the synthetic requirements for aqueous aldol catalysis and the feasibility of the enamine mechanism under physiological conditions have given rise to the hypothesis that ingested molecules, such as abused drugs, could participate in reactions utilizing an enamine intermediate in vivo. The chemical reactivity of exogenous drugs with amine functionalities was initially examined in the context of the Maillard reaction, or nonenzymatic browning. The heating of reducing sugars with amino acids yields a brown solution; studies of this reaction were originally applied to food chemistry for the production of distinct flavors and aromas. Further research has since revealed numerous instances in which the in vivo production of advanced glycation end products (AGEs) through the Maillard reaction contribute to the pathology of disease states. Specifically, the modification of long-lived proteins by glycation and glycoxidation and the accumulation of these AGEs compromise the original function of such proteins and change the mechanical properties of

  2. Consequences of Advanced Glycation End Products Accumulation in Chronic Kidney Disease and Clinical Usefulness of Their Assessment Using a Non-invasive Technique - Skin Autofluorescence.

    PubMed

    Oleniuc, Mihaela; Secara, Irina; Onofriescu, Mihai; Hogas, Simona; Voroneanu, Luminita; Siriopol, Dimitrie; Covic, Adrian

    2011-10-01

    Accelerated formation and accumulation of advanced glycation end-products occur under circumstances of increased supply of substrates such as hyperglycaemic or oxidative stress and in age-related and chronic diseases like diabetes mellitus, chronic renal failure, neurodegenerative diseases, osteoarthritis and also non-diabetic atherosclerosis and chronic heart failure. Advanced glycation end-products accumulation occurs especially on long-lived proteins such as collagen in the skin and in vascular basement membranes leading to vascular damage. Adequate renal clearance capacity is an important factor in the effective removal of advanced glycation end-products. The Autofluorescence Reader was developed as a marker, representative for tissue advanced glycation end-products accumulation, easily applicable in a clinical setting, initially for predicting diabetes related complications. Studies have already shown a relationship between skin autofluorescence and diabetes complications, as well as its predictive value for total and cardiovascular mortality in type 2 diabetes. Moreover skin autofluorescence was demonstrated to be superior to Haemoglobin A1c and other conventional risk factors. Advanced glycation end-products have been proposed as a novel factor involved in the development and progression of chronic heart failure. Assessment of advanced glycation end-products accumulation in end-stage renal disease and undergoing renal replacement therapies patients has become of great importance. Cardiovascular and connective tissue disorders are very common in patients with end-stage renal disease, and the accumulation of advanced glycation end-products is significantly increased in these patients. Mortality is markedly increased in patients with decreased kidney function, particularly in patients with end-stage renal disease. Skin advanced glycation end-products levels are strong predictors of survival in haemodialysis patients independent of other established risk factors

  3. 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

  4. Ginseng improves cognitive deficit via the RAGE/NF-κB pathway in advanced glycation end product-induced rats

    PubMed Central

    Tan, Xiaobin; Gu, Junfei; Zhao, Bingjie; Wang, Shuyuan; Yuan, Jiarui; Wang, Chunfei; Chen, Juan; Liu, Jiping; Feng, Liang; Jia, Xiaobin

    2014-01-01

    Background Ginseng, the root of Panax ginseng (PG), is used widely as a herbal medicine to prevent and treat various diseases. Panax ginseng has pharmacological effects on neurodegenerative diseases such as Alzheimer's disease (AD). The present study evaluated the neuroprotective effects of PG and its possible neuroprotective mechanisms in advanced glycation end product (AGE)-induced AD in a rat model. Methods Advanced glycation end products were injected bilaterally into the CA3 region of the rats' brains. The Morris water maze test and step-down type passive avoidance test were performed to evaluate their memory and cognitive abilities. The oxidation indexes in the hippocampus were detected. Immunohistochemistry was conducted to visualize the receptors for advanced glycation end products (RAGEs) and nuclear factor-kappa-light-chain-enhancer of activated B cell (NF-κB). Results Behavioral results showed that PG (1 g/kg, 0.5 g/kg, and 0.25 g/kg) significantly shortened the escape latency, remarkably increased the number of crossing times, significantly decreased the number of errors, and prolonged the latency in rats with AGE-induced AD. Panax ginseng also significantly reduced the malondialdehyde level, increased the glutathione content, and increased superoxide dismutase activity in the hippocampus. Panax ginseng significantly decreased the expression of RAGE and NF-κB. The blockade of anti-RAGE antibody could significantly reduce AGE-induced impairments and regulate these expressions. Conclusion Our results demonstrated that PG significantly inhibits AGE-induced memory impairment and attenuates Alzheimer-like pathophysiological changes. These neuroprotective effects of PG may be associated with the RAGE/NF-κB pathway. Our results provided the experimental basis for applying PG in preventing and treating AD. PMID:26045684

  5. Role of advanced glycation end products (AGEs) and their receptor (RAGE) in the pathogenesis of diabetic microangiopathy.

    PubMed

    Yamagishi, S; Takeuchi, M; Inagaki, Y; Nakamura, K; Imaizumi, T

    2003-01-01

    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 pathogenesis of diabetic micro- and macrovascular complications via various metabolic derangements. In this review, we discuss the molecular mechanisms of diabetic retinopathy and nephropathy, especially focusing on advanced glycation end products (AGEs) and their receptor (RAGE) system. Several types of AGE inhibitors and their therapeutic implications in diseases, including diabetic microangiopathy, will be discussed in the next review article. PMID:15224502

  6. The receptor for advanced glycation end products (RAGE) affects T cell differentiation in OVA induced asthma.

    PubMed

    Akirav, Eitan M; Henegariu, Octavian; Preston-Hurlburt, Paula; Schmidt, Ann Marie; Clynes, Raphael; Herold, Kevan C

    2014-01-01

    The receptor for glycation end products (RAGE) has been previously implicated in shaping the adaptive immune response. RAGE is expressed in T cells after activation and constitutively in T cells from patients with diabetes. The effects of RAGE on adaptive immune responses are not clear: Previous reports show that RAGE blockade affects Th1 responses. To clarify the role of RAGE in adaptive immune responses and the mechanisms of its effects, we examined whether RAGE plays a role in T cell activation in a Th2 response involving ovalbumin (OVA)-induced asthma in mice. WT and RAGE deficient wild-type and OT-II mice, expressing a T cell receptor specific for OVA, were immunized intranasally with OVA. Lung cellular infiltration and T cell responses were analyzed by immunostaining, FACS, and multiplex bead analyses for cytokines. RAGE deficient mice showed reduced cellular infiltration in the bronchial alveolar lavage fluid and impaired T cell activation in the mediastinal lymph nodes when compared with WT mice. In addition, RAGE deficiency resulted in reduced OT-II T cell infiltration of the lung and impaired IFNγ and IL-5 production when compared with WT mice and reduced infiltration when transferred into WT hosts. When cultured under conditions favoring the differentiation of T cells subsets, RAGE deficient T cells showed reduced production of IFNγ but increased production of IL-17. Our data show a stimulatory role for RAGE in T activation in OVA-induced asthma. This role is largely mediated by the effects of RAGE on T cell proliferation and differentiation. These findings suggest that RAGE may play a regulatory role in T cell responses following immune activation.

  7. 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.

  8. Effects of combined lipoic acid and pyridoxine on albuminuria, advanced glycation end-products, and blood pressure in diabetic nephropathy.

    PubMed

    Noori, Nazanin; Tabibi, Hadi; Hosseinpanah, Farhad; Hedayati, Mehdi; Nafar, Mohsen

    2013-01-01

    This study was designed to investigate the effects of combined administration of lipoic acid and pyridoxine on albuminuria, oxidative stress, blood pressure, serum advanced glycation end-products, nitric oxide (NO), and endothelin-1 in patients with diabetic nephropathy. Thirty-four patients were randomly assigned to either a supplement group or a placebo group. The patients in the supplement group received 800 mg lipoic acid and 80 mg pyridoxine daily for 12 weeks, whereas the placebo group received corresponding placebos. Urinary albumin, serum malondialdehyde (MDA), and systolic blood pressure decreased significantly in the supplement group compared to the placebo group (p < 0.05). Serum NO increased in the supplement group compared to the placebo group (p < 0.05). Serum pentosidine and carboxymethyl lysine decreased significantly in the supplement group at the end of week 12 compared to baseline (p < 0.05). No statistically significant differences were observed between the two groups in mean changes of serum endothelin-1, glucose, and diastolic blood pressure. The present study indicates that combined administration of lipoic acid and pyridoxine improves albuminuria in patients with diabetic nephropathy by reducing oxidative stress, advanced glycation end-products, and systolic blood pressure. The reduction in microalbuminuria may be of benefit in retarding the progression of diabetic nephropathy.

  9. 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.

  10. 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

  11. 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.

  12. 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

  13. 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

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

    PubMed Central

    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

  15. 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

  16. Serum Carboxymethyl-lysine, an Advanced Glycation End Product, is Associated with Increased Aortic Pulse Wave Velocity in Adults

    PubMed Central

    Semba, Richard D.; Najjar, Samer S.; Sun, Kai; Lakatta, Edward G.; Ferrucci, Luigi

    2008-01-01

    Background The relationship between advanced glycation end products and arterial stiffness has previously been examined in highly selected groups of patients with diabetes or hypertension. Our aim was to determine whether elevated serum advanced glycation end products are associated with increased arterial stiffness in relatively healthy, community-dwelling adults. Methods Aortic pulse wave velocity (PWV), an index of aortic stiffness, and serum AGEs, as represented by the specific AGE, serum carboxymethyl-lysine (CML), were measured in 493 adults, aged 26-93 years, who participated in the Baltimore Longitudinal Study of Aging. Results Mean (SD) PWV (m/sec) was 6.6 (1.8) m/sec. Mean CML was 0.47 (0.13) μg/mL. Serum CML (per 1 Standard Deviation [S.D.]) was associated with PWV (beta = 0.16, standard error [S.E.] = 0.07, P = 0.02), adjusting for age, sex, body mass index, mean arterial pressure, fasting plasma glucose, high density lipoprotein cholesterol, smoking, and other covariates. After excluding all diabetic patients, serum CML (per 1 S.D.) was associated with PWV (beta = 0.18, S.E. = 0.07, P = 0.009), adjusting for the same covariates. Conclusions Elevated AGEs are associated with increased arterial stiffness, a known predictor of adverse cardiovascular outcomes, among relatively healthy community-dwelling adults. Interventions to lower levels of AGEs, such as altering the pattern of dietary intake, warrant examination as putative novel strategies to lower arterial stiffness in adults. PMID:19023277

  17. Advanced glycation end products, carotid atherosclerosis, and circulating endothelial progenitor cells in patients with end-stage renal disease.

    PubMed

    Ueno, Hiroki; Koyama, Hidenori; Fukumoto, Shinya; Tanaka, Shinji; Shoji, Takuhito; Shoji, Tetsuo; Emoto, Masanori; Tahara, Hideki; Inaba, Masaaki; Kakiya, Ryusuke; Tabata, Tsutomu; Miyata, Toshio; Nishizawa, Yoshiki

    2011-04-01

    Numbers of endothelial progenitor cells (EPCs) have been shown to be decreased in subjects with end-stage renal disease (ESRD), the mechanism of which remained poorly understood. In this study, mutual association among circulating EPC levels, carotid atherosclerosis, serum pentosidine, and skin autofluorescence, a recently established noninvasive measure of advanced glycation end products accumulation, was examined in 212 ESRD subjects undergoing hemodialysis. Numbers of circulating EPCs were measured as CD34+ CD133+ CD45(low) VEGFR2+ cells and progenitor cells as CD34+ CD133+ CD45(low) fraction by flow cytometry. Skin autofluorescence was assessed by the autofluorescence reader; and serum pentosidine, by enzyme-linked immunosorbent assay. Carotid atherosclerosis was determined as intimal-medial thickness (IMT) measured by ultrasound. Circulating EPCs were significantly and inversely correlated with skin autofluorescence in ESRD subjects (R = -0.216, P = .002), but not with serum pentosidine (R = -0.079, P = .25). Circulating EPCs tended to be inversely associated with IMT (R = -0.125, P = .069). Intimal-medial thickness was also tended to be correlated positively with skin autofluorescence (R = 0.133, P = .054) and significantly with serum pentosidine (R = 0.159, P = .019). Stepwise multiple regression analyses reveal that skin autofluorescence, but not serum pentosidine and IMT, was independently associated with low circulating EPCs. Of note, skin autofluorescence was also inversely and independently associated with circulating progenitor cells. Thus, tissue accumulated, but not circulating, advanced glycation end products may be a determinant of a decrease in circulating EPCs in ESRD subjects.

  18. 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

  19. 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.

  20. Advanced glycation end products, carotid atherosclerosis, and circulating endothelial progenitor cells in patients with end-stage renal disease.

    PubMed

    Ueno, Hiroki; Koyama, Hidenori; Fukumoto, Shinya; Tanaka, Shinji; Shoji, Takuhito; Shoji, Tetsuo; Emoto, Masanori; Tahara, Hideki; Inaba, Masaaki; Kakiya, Ryusuke; Tabata, Tsutomu; Miyata, Toshio; Nishizawa, Yoshiki

    2011-04-01

    Numbers of endothelial progenitor cells (EPCs) have been shown to be decreased in subjects with end-stage renal disease (ESRD), the mechanism of which remained poorly understood. In this study, mutual association among circulating EPC levels, carotid atherosclerosis, serum pentosidine, and skin autofluorescence, a recently established noninvasive measure of advanced glycation end products accumulation, was examined in 212 ESRD subjects undergoing hemodialysis. Numbers of circulating EPCs were measured as CD34+ CD133+ CD45(low) VEGFR2+ cells and progenitor cells as CD34+ CD133+ CD45(low) fraction by flow cytometry. Skin autofluorescence was assessed by the autofluorescence reader; and serum pentosidine, by enzyme-linked immunosorbent assay. Carotid atherosclerosis was determined as intimal-medial thickness (IMT) measured by ultrasound. Circulating EPCs were significantly and inversely correlated with skin autofluorescence in ESRD subjects (R = -0.216, P = .002), but not with serum pentosidine (R = -0.079, P = .25). Circulating EPCs tended to be inversely associated with IMT (R = -0.125, P = .069). Intimal-medial thickness was also tended to be correlated positively with skin autofluorescence (R = 0.133, P = .054) and significantly with serum pentosidine (R = 0.159, P = .019). Stepwise multiple regression analyses reveal that skin autofluorescence, but not serum pentosidine and IMT, was independently associated with low circulating EPCs. Of note, skin autofluorescence was also inversely and independently associated with circulating progenitor cells. Thus, tissue accumulated, but not circulating, advanced glycation end products may be a determinant of a decrease in circulating EPCs in ESRD subjects. PMID:20494372

  1. Consequences of Advanced Glycation End Products Accumulation in Chronic Kidney Disease and Clinical Usefulness of Their Assessment Using a Non-invasive Technique - Skin Autofluorescence.

    PubMed

    Oleniuc, Mihaela; Secara, Irina; Onofriescu, Mihai; Hogas, Simona; Voroneanu, Luminita; Siriopol, Dimitrie; Covic, Adrian

    2011-10-01

    Accelerated formation and accumulation of advanced glycation end-products occur under circumstances of increased supply of substrates such as hyperglycaemic or oxidative stress and in age-related and chronic diseases like diabetes mellitus, chronic renal failure, neurodegenerative diseases, osteoarthritis and also non-diabetic atherosclerosis and chronic heart failure. Advanced glycation end-products accumulation occurs especially on long-lived proteins such as collagen in the skin and in vascular basement membranes leading to vascular damage. Adequate renal clearance capacity is an important factor in the effective removal of advanced glycation end-products. The Autofluorescence Reader was developed as a marker, representative for tissue advanced glycation end-products accumulation, easily applicable in a clinical setting, initially for predicting diabetes related complications. Studies have already shown a relationship between skin autofluorescence and diabetes complications, as well as its predictive value for total and cardiovascular mortality in type 2 diabetes. Moreover skin autofluorescence was demonstrated to be superior to Haemoglobin A1c and other conventional risk factors. Advanced glycation end-products have been proposed as a novel factor involved in the development and progression of chronic heart failure. Assessment of advanced glycation end-products accumulation in end-stage renal disease and undergoing renal replacement therapies patients has become of great importance. Cardiovascular and connective tissue disorders are very common in patients with end-stage renal disease, and the accumulation of advanced glycation end-products is significantly increased in these patients. Mortality is markedly increased in patients with decreased kidney function, particularly in patients with end-stage renal disease. Skin advanced glycation end-products levels are strong predictors of survival in haemodialysis patients independent of other established risk factors

  2. Anti-Advanced Glycation End-product and Free Radical Scavenging Activity of Plants from the Yucatecan Flora

    PubMed Central

    Dzib-Guerra, Wendy del C.; Escalante-Erosa, Fabiola; García-Sosa, Karlina; Derbré, Séverine; Blanchard, Patricia; Richomme, Pascal; Peña-Rodríguez, Luis M.

    2016-01-01

    Background: Formation and accumulation of advanced glycation end-products (AGE) is recognized as a major pathogenic process in diabetic complications, atherosclerosis and cardiovascular diseases. In addition, reactive oxygen species and free radicals have also been reported to participate in AGE formation and in cell damage. Natural products with antioxidant and antiAGE activity have great therapeutic potential in the treatment of diabetes, hypertension and related complications. Objective: to test ethanolic extracts and aqueous-traditional preparations of plants used to treat diabetes, hypertension and obesity in Yucatecan traditional medicine for their anti-AGE and free radical scavenging activities. Materials and Methods: ethanolic extracts of leaves, stems and roots of nine medicinal plants, together with their traditional preparations, were prepared and tested for their anti-AGE and antioxidant activities using the inhibition of advanced glycation end products and DPPH radical scavenging assays, respectively. Results: the root extract of C. fistula (IC50= 0.1 mg/mL) and the leaf extract of P. auritum (IC50= 0.35 mg/mL) presented significant activity against vesperlysine and pentosidine-like AGE. Although none of the aqueous traditional preparations showed significant activity in the anti-AGE assay, both the traditional preparations and the ethanolic extracts of E. tinifolia, M. zapota, O. campechianum and P. auritum showed significant activity in the DPPH reduction assay. Conclusions: the results suggest that the metabolites responsible for the detected radical-scavenging activity are different to those involved in inhibiting AGE formation; however, the extracts with antioxidant activity may contain other metabolites which are able to prevent AGE formation through a different mechanism. SUMMARY Ethanolic extracts from nine plants used to treat diabetes, hypertension and obesity in Yucatecan traditional medicine were tested for their anti-AGE and free radical

  3. Anti-Advanced Glycation End-product and Free Radical Scavenging Activity of Plants from the Yucatecan Flora

    PubMed Central

    Dzib-Guerra, Wendy del C.; Escalante-Erosa, Fabiola; García-Sosa, Karlina; Derbré, Séverine; Blanchard, Patricia; Richomme, Pascal; Peña-Rodríguez, Luis M.

    2016-01-01

    Background: Formation and accumulation of advanced glycation end-products (AGE) is recognized as a major pathogenic process in diabetic complications, atherosclerosis and cardiovascular diseases. In addition, reactive oxygen species and free radicals have also been reported to participate in AGE formation and in cell damage. Natural products with antioxidant and antiAGE activity have great therapeutic potential in the treatment of diabetes, hypertension and related complications. Objective: to test ethanolic extracts and aqueous-traditional preparations of plants used to treat diabetes, hypertension and obesity in Yucatecan traditional medicine for their anti-AGE and free radical scavenging activities. Materials and Methods: ethanolic extracts of leaves, stems and roots of nine medicinal plants, together with their traditional preparations, were prepared and tested for their anti-AGE and antioxidant activities using the inhibition of advanced glycation end products and DPPH radical scavenging assays, respectively. Results: the root extract of C. fistula (IC50= 0.1 mg/mL) and the leaf extract of P. auritum (IC50= 0.35 mg/mL) presented significant activity against vesperlysine and pentosidine-like AGE. Although none of the aqueous traditional preparations showed significant activity in the anti-AGE assay, both the traditional preparations and the ethanolic extracts of E. tinifolia, M. zapota, O. campechianum and P. auritum showed significant activity in the DPPH reduction assay. Conclusions: the results suggest that the metabolites responsible for the detected radical-scavenging activity are different to those involved in inhibiting AGE formation; however, the extracts with antioxidant activity may contain other metabolites which are able to prevent AGE formation through a different mechanism. SUMMARY Ethanolic extracts from nine plants used to treat diabetes, hypertension and obesity in Yucatecan traditional medicine were tested for their anti-AGE and free radical

  4. Low levels of soluble receptor for advanced glycation end products in non-ST elevation myocardial infarction patients

    PubMed Central

    McNair, Erick D; Wells, Calvin R; Qureshi, A Mabood; Basran, Rashpal S; Pearce, Colin; Orvold, Jason; Devilliers, Jacobus; Prasad, Kailash

    2009-01-01

    BACKGROUND: Interaction of the receptors for advanced glycation end products (RAGEs) with advanced glycation end products (AGEs) results in expression of inflammatory mediators (tumor necrosis factor-alpha [TNF-α] and soluble vascular cell adhesion molecule-1 [sVCAM-1]), activation of nuclear factor-kappa B and induction of oxidative stress – all of which have been implicated in atherosclerosis. Soluble RAGE (sRAGE) acts as a decoy for the RAGE ligand and is protective against atherosclerosis. OBJECTIVES: To determine whether levels of serum sRAGE are lower, and whether levels of serum AGEs, TNF-α and sVCAM-1 are higher in non-ST elevation myocardial infarction (NSTEMI) patients than in healthy control subjects; and whether sRAGE or the ratio of AGEs to sRAGE (AGEs/sRAGE) is a predictor/biomarker of NSTEMI. METHODS: Serum levels of sRAGE, AGEs, TNF-α and sVCAM-1 were measured in 46 men with NSTEMI and 28 age- and sex-matched control subjects. Angiography was performed in the NSTEMI patients. RESULTS: sRAGE levels were lower, and levels of AGEs, TNF-α, sVCAM-1 and AGEs/sRAGE were higher in NSTEMI patients than in control subjects. sRAGE levels were negatively correlated with the number of diseased coronary vessels, serum AGEs, AGEs/sRAGE, TNF-α and sVCAM-1. The sensitivity of the AGEs/sRAGE test is greater than that of the sRAGE test, while the specificity and predictive values of the sRAGE test are greater than those of the AGEs/sRAGE test for identifying NSTEMI patients. CONCLUSIONS: Serum levels of sRAGE were low in NSTEMI patients, and were negatively correlated with extent of lesion, inflammatory mediators, AGEs and AGEs/sRAGE. Both sRAGE and AGEs/sRAGE may serve as biomarkers/predictors for identifying NSTEMI patients. PMID:22477551

  5. Advanced glycation end products as biomarkers and gerontotoxins - A basis to explore methylglyoxal-lowering agents for Alzheimer's disease?

    PubMed

    Krautwald, Martina; Münch, Gerald

    2010-10-01

    Alzheimer's disease (AD) is the most common dementing disorder of late life. Although there might be various different triggering events in the early stages of the disease, they seem to converge on a few characteristic final pathways in the late stages, characterized by inflammation and neurodegeneration. In this review, we put forward the hypothesis that advanced glycation end products (AGEs) and their precursors, including methylglyoxal, are both biomarkers and causative agents ("gerontotoxins") characteristic for this disorder. Accumulation of AGEs is a normal feature of aging, but is accelerated in AD, where AGEs can be detected in amyloid plaques and neurofibrillary tangles. AGE modification may explain many of the neuropathological and biochemical features of AD such as extensive protein cross-linking, inflammation, oxidative stress and neuronal cell death. We suggest that methylglyoxal is one of the major carbonyl species responsible for the formation of AGEs. We propose that one promising pharmacological approach to prevent the formation of AGEs would be to lower the methylglyoxal concentration. This can be achieved, for example, by decreasing the concentration of methylglyoxal precursors such as d-glyceraldehyde-3-phosphate by allowing a higher flux through the pentose phosphate pathway or by increasing methylglyoxal detoxification through the glyoxalase system. Alternatively, methylglyoxal could be scavenged by various types of carbonyl scavengers. PMID:20211718

  6. 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.

  7. 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.

  8. Involvement of Endoplasmic Reticulum Stress, Autophagy, and Apoptosis in Advanced Glycation End Products-Induced Glomerular Mesangial Cell Injury

    PubMed Central

    Chiang, Chih-Kang; Wang, Ching-Chia; Lu, Tien-Fong; Huang, Kuo-How; Sheu, Meei-Ling; Liu, Shing-Hwa; Hung, Kuan-Yu

    2016-01-01

    Advanced glycation end-products (AGEs)-induced mesangial cell death is one of major causes of glomerulus dysfunction in diabetic nephropathy. Both endoplasmic reticulum (ER) stress and autophagy are adaptive responses in cells under environmental stress and participate in the renal diseases. The role of ER stress and autophagy in AGEs-induced mesangial cell death is still unclear. Here, we investigated the effect and mechanism of AGEs on glomerular mesangial cells. AGEs dose-dependently decreased mesangial cell viability and induced cell apoptosis. AGEs also induced ER stress signals in a time- and dose-dependent manner. Inhibition of ER stress with 4-phenylbutyric acid effectively inhibited the activation of eIF2α and CHOP signals and reversed AGEs-induced cell apoptosis. AGEs also activated LC-3 cleavage, increased Atg5 expression, and decreased p62 expression, which indicated the autophagy induction in mesangial cells. Inhibition of autophagy by Atg5 siRNAs transfection aggravated AGEs-induced mesangial cell apoptosis. Moreover, ER stress inhibition by 4-phenylbutyric acid significantly reversed AGEs-induced autophagy, but autophagy inhibition did not influence the AGEs-induced ER stress-related signals activation. These results suggest that AGEs induce mesangial cell apoptosis via an ER stress-triggered signaling pathway. Atg5-dependent autophagy plays a protective role. These findings may offer a new strategy against AGEs toxicity in the kidney. PMID:27665710

  9. 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

  10. 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.

  11. The receptor for advanced glycation end products influences the expression of its S100 protein ligands in melanoma tumors.

    PubMed

    Meghnani, Varsha; Wagh, Anil; Indurthi, Venkata S K; Koladia, Mohit; Vetter, Stefan W; Law, Benedict; Leclerc, Estelle

    2014-12-01

    Recent studies have suggested that the receptor for advanced glycation end products (RAGE) participates in melanoma progression by promoting tumor growth. However, the mechanisms of RAGE activation in melanoma tumors are not clearly understood. To get deeper insights into these mechanisms, we transfected a melanoma cell line, which was established from a human melanoma primary tumor, with RAGE, and studied the effect of RAGE overexpression on cell proliferation and migration in vitro. We observed that overexpression of RAGE in these cells not only resulted in significantly increased migration rates compared to control cells, but also in decreased proliferation rates (Meghnani et al., 2014). In the present study, we compared the growth of xenograft tumors established from RAGE overexpressing WM115 cells, to that of control cells. We observed that when implanted in mice, RAGE overexpressing cells generated tumors faster than control cells. Analysis of protein tumor extracts showed increased levels of the RAGE ligands S100B, S100A2, S100A4, S100A6 and S100A10 in RAGE overexpressing tumors compared to control tumors. We show that the tumor growth was significantly reduced when the mice were treated with anti-RAGE antibodies, suggesting that RAGE, and probably several S100 proteins, were involved in tumor growth. We further demonstrate that the anti-RAGE antibody treatment significantly enhanced the efficacy of the alkylating drug dacarbazine in reducing the growth rate of RAGE overexpressing tumors. PMID:25310905

  12. An Emerging Role of Glucagon-Like Peptide-1 in Preventing Advanced-Glycation-End-Product-Mediated Damages in Diabetes

    PubMed Central

    Puddu, Alessandra; Mach, François; Nencioni, Alessio; Viviani, Giorgio Luciano; Montecucco, Fabrizio

    2013-01-01

    Glucagon-like peptide-1 (GLP-1) is a gut hormone produced in the intestinal epithelial endocrine L cells by differential processing of the proglucagon gene. Released in response to the nutrient ingestion, GLP-1 plays an important role in maintaining glucose homeostasis. GLP-1 has been shown to regulate blood glucose levels by stimulating glucose-dependent insulin secretion and inhibiting glucagon secretion, gastric emptying, and food intake. These antidiabetic activities highlight GLP-1 as a potential therapeutic molecule in the clinical management of type 2 diabetes, (a disease characterized by progressive decline of beta-cell function and mass, increased insulin resistance, and final hyperglycemia). Since chronic hyperglycemia contributed to the acceleration of the formation of Advanced Glycation End-Products (AGEs, a heterogeneous group of compounds derived from the nonenzymatic reaction of reducing sugars with free amino groups of proteins implicated in vascular diabetic complications), the administration of GLP-1 might directly counteract diabetes pathophysiological processes (such as pancreatic β-cell dysfunction). This paper outlines evidence on the protective role of GLP-1 in preventing the deleterious effects mediated by AGEs in type 2 diabetes. PMID:23365488

  13. 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

  14. 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

  15. 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

  16. 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

  17. Advanced glycation end products are eliminated by scavenger-receptor-mediated endocytosis in hepatic sinusoidal Kupffer and endothelial cells.

    PubMed Central

    Smedsrød, B; Melkko, J; Araki, N; Sano, H; Horiuchi, S

    1997-01-01

    Long-term incubation of proteins with glucose leads to the formation of advanced glycation end products (AGE). Physiological aspects of the catabolism of non-enzymically glycated proteins were studied in vivo and in vitro. AGE-modified BSA (AGE-BSA) was a mixture of high-Mr (cross-linked), monomeric and low-Mr (fragmented) AGE-BSA. After intravenous administration in rat, all three fractions of AGE-BSA accumulated extremely rapidly and almost exclusively in liver. Uptake in liver endothelial, Kupffer and parenchymal cells accounted for approx. 60%, 25% and 10-15% respectively of hepatic elimination. Both cross-linked and monomeric AGE-BSA were efficiently taken up and degraded in cultures of purified liver endothelial and Kupffer cells. Endocytosis of AGE-BSA by these cells was inhibited by several ligands for the scavenger receptor. Although 125I-Hb was not endocytosed in vitro, 125I-AGE-Hb was effectively endocytosed by a mechanism that was subject to inhibition by AGE-BSA. Endocytosis of N-terminal propeptide of type I procollagen, a physiological ligand for the scavenger receptor, was effectively inhibited by AGE-Hb and AGE-BSA. We conclude that AGE-modification renders macromolecules susceptible for elimination via the scavenger receptor of both liver endothelial and Kupffer cells. PMID:9065778

  18. The downregulation of thioredoxin accelerated Neuro2a cell apoptosis induced by advanced glycation end product via activating several pathways.

    PubMed

    Ren, Xiang; Ma, Haiying; Qiu, Yuanyuan; Liu, Bo; Qi, Hui; Li, Zeyu; Kong, Hui; Kong, Li

    2015-08-01

    Thioredoxin (Trx), a 12 kDa protein, has different functions in different cellular environments, playing important anti-oxidative and anti-apoptotic roles and regulating the expression of transcription factors. Advanced glycation end products (AGEs) are a heterogeneous group of irreversible adducts from glucose-protein condensation reactions and are considered crucial to the development of diabetic nephropathy, retinopathy, neurodegeneration and atherosclerosis. The aim of this study was to use a Trx inhibitor to investigate the effects and mechanism of Trx down-regulation on AGE-induced Neuro2a cell apoptosis. Neuro2a cells were cultured in vitro and treated with different conditions. The apoptosis and proliferation of Neuro2a cells were detected using flow cytometry, DNA-Ladder and CCK8 assays. Rho 123 was used to detect the mitochondrial membrane potential. ROS generation and caspase3 activity were detected using a DCFH-DA probe and micro-plate reader. Western blotting and real-time PCR were used to detect the expression of proteins and genes. We found that the down-regulation of thioredoxin could accelerate AGE-induced apoptosis in Neuro2a cells. A possible underlying mechanism is that the down-regulation of thioredoxin stimulated the up-regulation of ASK1, p-JNK, PTEN, and Txnip, as well as the down-regulation of p-AKT, ultimately increasing ROS levels and caspase3 activity.

  19. 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

  20. 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

  1. 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.

  2. 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

  3. 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

  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.

  5. The downregulation of thioredoxin accelerated Neuro2a cell apoptosis induced by advanced glycation end product via activating several pathways.

    PubMed

    Ren, Xiang; Ma, Haiying; Qiu, Yuanyuan; Liu, Bo; Qi, Hui; Li, Zeyu; Kong, Hui; Kong, Li

    2015-08-01

    Thioredoxin (Trx), a 12 kDa protein, has different functions in different cellular environments, playing important anti-oxidative and anti-apoptotic roles and regulating the expression of transcription factors. Advanced glycation end products (AGEs) are a heterogeneous group of irreversible adducts from glucose-protein condensation reactions and are considered crucial to the development of diabetic nephropathy, retinopathy, neurodegeneration and atherosclerosis. The aim of this study was to use a Trx inhibitor to investigate the effects and mechanism of Trx down-regulation on AGE-induced Neuro2a cell apoptosis. Neuro2a cells were cultured in vitro and treated with different conditions. The apoptosis and proliferation of Neuro2a cells were detected using flow cytometry, DNA-Ladder and CCK8 assays. Rho 123 was used to detect the mitochondrial membrane potential. ROS generation and caspase3 activity were detected using a DCFH-DA probe and micro-plate reader. Western blotting and real-time PCR were used to detect the expression of proteins and genes. We found that the down-regulation of thioredoxin could accelerate AGE-induced apoptosis in Neuro2a cells. A possible underlying mechanism is that the down-regulation of thioredoxin stimulated the up-regulation of ASK1, p-JNK, PTEN, and Txnip, as well as the down-regulation of p-AKT, ultimately increasing ROS levels and caspase3 activity. PMID:26142569

  6. 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

  7. 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

  8. 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

  9. Advanced glycation end-products in the peritoneal fluid and in the peritoneal membrane of continuous ambulant peritoneal dialysis patients.

    PubMed

    Mahiout, A; Ehlerding, G; Brunkhorst, R

    1996-01-01

    In patients on continuous ambulant peritoneal dialysis (CAPD) treatment, the peritoneal membrane is continuously exposed to the high glucose concentration contained in the dialysate. This may lead to the local generation of advanced glycation end-products (AGEs). To test this hypothesis we evaluated the plasma and dialysate AGE concentrations in five CAPD patients. The dialysate was measured after a 1 h and after a 12 h dwell time. Additionally, in two patients an immunohistochemical investigation of the peritoneal membrane for AGE was performed. For the determination of AGE an ELISA using a polyclonal antibody against AGE bovine serum albumin was used; the immunohistochemical staining was performed using the streptavidin-biotin complex method. We found only low concentrations of AGE in the dialysate after a 1 h dwell time; after 12 h, however, the dialysate AGE was even greater than the plasma concentration. In both peritoneal specimens we found positive staining for AGE in the interstitium of the mesothelial layer. The dialysate AGE contained a high proportion of high-molecular-weight AGE proteins and low-molecular-weight AGE was found to be in the same concentration range as the total serum AGE. We conclude that there is local generation of AGE in the peritoneal membrane and a 'washing out' of AGE from the peritoneal membrane during longer dwell times. We speculate that the accumulation of AGE might lead to some of the functional and morphological alterations observed after long-term CAPD.

  10. 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

  11. 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.

  12. 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.

  13. 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

  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.

  15. 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

  16. 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

  17. Rosiglitazone prevents advanced glycation end products-induced renal toxicity likely through suppression of plasminogen activator inhibitor-1.

    PubMed

    Yu, Xiaoyan; Li, Cai; Li, Xiaokun; Cai, Lu

    2007-04-01

    In the development of diabetic nephropathy, advanced glycation end products (AGEs) play a causative role via induction of extracellular matrix (ECM) accumulation. Plasminogen activator inhibitor-1 (PAI-1), as a major inhibitor of plasminogen activator that plays an important role in degrading ECM, was found to significantly increase in renal fibrotic diseases. Activation of peroxisome proliferator-activated receptor (PPAR)-gamma prevented diabetic nephropathy. The present study, therefore, was to define whether or not AGE-induced renal ECM accumulation and renal dysfunction are mediated by upregulation of PAI-1 expression and whether or not PPAR-gamma agonist can attenuate these AGE effects via suppressing PAI-1 expression. Rats were given AGEs alone by iv injection at 100 mg/kg daily with or without oral supplementation of PPAR-gamma agonist rosiglitazone (RGZ) at 2 mg/kg daily for 6 weeks. Results showed that AGEs induced a renal ECM accumulation, as shown by increases in periodic acid-Schiff-positive materials, fibronectin, and type IV collagen (Col IV) contents in glomeruli, and a mild renal dysfunction, as shown by an increase in urinary proteins. AGEs also caused an increase in PAI-1 expression and a decrease in plasminogen activator bioactivity in the kidney. Treatment with RGZ significantly ameliorated AGE-induced renal ECM accumulation, proteinuria, and PAI-1 upregulation. Direct exposure of rat mesangial cells to AGEs in vitro induced increases in fibronectin and Col IV syntheses along with an increase in PAI-1 expression, effects significantly attenuated by RGZ. Preincubation of PAI-1 antibody to AGE-treated mesangial cells completely prevented AGE-induced fibronectin and Col IV production. These results suggest that upregulation of PAI-1 expression plays a critical role in AGE-induced renal ECM accumulation. Renal protection of RGZ from AGEs may be associated with the suppression of PAI-1 expression through PPAR-dependent and independent mechanisms.

  18. Curcumin inhibits advanced glycation end product-induced oxidative stress and inflammatory responses in endothelial cell damage via trapping methylglyoxal.

    PubMed

    Sun, Yan Ping; Gu, Jun Fei; Tan, Xiao Bin; Wang, Chun Fei; Jia, Xiao Bin; Feng, Liang; Liu, Ji Ping

    2016-02-01

    Methylglyoxal (MGO)-induced carbonyl stress and pro-inflammatory responses have been suggested to contribute to endothelial dysfunction. Curcumin (Cur), a polyphenolic compound from Curcuma longa L., may protect endothelial cells against carbonyl stress-induced damage by trapping dicarbonyl compounds such as MGO. However, Cur-MGO adducts have not been studied in depth to date and it remains to be known whether Cur-MGO adducts are able to attenuate endothelial damage by trapping MGO. In the present study, 1,2-diaminobenzene was reacted with MGO to ensure the reliability of the reaction system. Cur was demonstrated to trap MGO at a 1:1 ratio to form adducts 1, 2 and 3 within 720 min. The structures of these adducts were identified by high-performance liquid chromatography/electrospray ionization tandem mass spectrometry. The kinetic curves of Cur (10(-7), 10(-6) and 10(-5) M) were measured from 0-168 h by fluorescent intensity. Cur significantly inhibited the formation of advanced glycation end products (AGEs). The differences in oxidative damage and the levels of pro-inflammatory cytokines following MGO + HSA or Cur-MGO treatment were investigated in human umbilical vein endothelial cells (HUVECs). Exposure of HUVECs to the Cur-MGO reaction adducts significantly reduced the intracellular ROS levels and improved cell viability compared with MGO alone. Furthermore, there was a significant reduction in the expression levels of transforming growth factor-β1 and intercellular adhesion molecule(-1) following treatment with Cur-MGO adducts compared with MGO alone. These results provide further evidence that the trapping of MGO by Cur inhibits the formation of AGEs. The current study indicates that the protective effect of Cur on carbonyl stress and pro-inflammatory responses in endothelial damage occurs via the trapping of MGO. PMID:26718010

  19. Advanced glycation end products promote hepatosteatosis by interfering with SCAP-SREBP pathway in fructose-drinking mice.

    PubMed

    Mastrocola, Raffaella; Collino, Massimo; Rogazzo, Mara; Medana, Claudio; Nigro, Debora; Boccuzzi, Giuseppe; Aragno, Manuela

    2013-09-15

    Clinical studies have linked the increased consumption of fructose to the development of obesity, dyslipidemia, and impaired glucose tolerance, and a role in hepatosteatosis development is presumed. Fructose can undergo a nonenzymatic reaction from which advanced glycation end products (AGEs) are derived, leading to the formation of dysfunctional, fructosylated proteins; however, the in vivo formation of AGEs from fructose is still less known than that from glucose. In the present study C57Bl/6J mice received 15% (wt/vol) fructose (FRT) or 15% (wt/vol) glucose (GLC) in water to drink for 30 wk, resembling human habit to consume sugary drinks. At the end of the protocol both FRT- and GLC-drinking mice had increased fasting glycemia, glucose intolerance, altered plasma lipid profile, and marked hepatosteatosis. FRT mice had higher hepatic triglycerides deposition than GLC, paralleled by a greater increased expression and activity of the sterol regulatory element-binding protein 1 (SREBP1), the transcription factor responsible for the de novo lipogenesis, and of its activating protein SCAP. LC-MS analysis showed a different pattern of AGE production in liver tissue between FRT and GLC mice, with larger amount of carboxymethyl lysine (CML) generated by fructose. Double immunofluorescence and coimmunoprecipitation analysis revealed an interaction between CML and SCAP that could lead to prolonged activation of SREBP1. Overall, the high levels of CML and activation of SCAP/SREBP pathway associated to high fructose exposure here reported may suggest a key role of this signaling pathway in mediating fructose-induced lipogenesis.

  20. Advanced Glycation End Product Receptor-1 Transgenic Mice Are Resistant to Inflammation, Oxidative Stress, and Post-Injury Intimal Hyperplasia

    PubMed Central

    Torreggiani, Massimo; Liu, Huixian; Wu, Jin; Zheng, Feng; Cai, Weijing; Striker, Gary; Vlassara, Helen

    2009-01-01

    The high levels of oxidative stress (OS) and inflammation associated with cardiovascular disease are linked to pro-oxidants such as advanced glycation end products (AGEs). AGEs interact with multiple receptors, including receptor 1 (AGER1), which promotes AGE removal and blocks OS and inflammation, and RAGE, which enhances inflammation. In this study, we evaluated metabolic and vascular changes in AGER1 transgenic mice (AGER1-tg) subjected to an atherogenic diet and arterial wire-injury. Both baseline and postatherogenic diet serum and tissue AGEs as well as plasma 8-isoprostane levels were lower in AGER1-tg mice than in wild-type mice. The levels of injected 125I-AGE in tissues were decreased as well in AGER1-tg mice. After ingesting a high-fat diet, AGER1-tg mice had a normal glucose tolerance and only 7% were hyperglycemic, whereas 53% of wild-type mice had stable hyperglycemia. After wire-injury, intimal lesions in AGER1-tg mice were small, whereas wild-type mice had diffuse intimal hyperplasia, a high intima/media ratio, and inflammatory cell infiltrates. In addition, AGER1 staining, prominent in AGER1-tg mice, was attenuated in 30 to 40% of wild-type cells, although all cells were strongly positive for AGEs. Thus, AGER1 overexpression in mice reduces basal levels of AGEs and OS, enhances resistance to diet-induced hyperglycemia and OS, and protects against injury-induced arterial intimal hyperplasia and inflammation, providing protection against OS and inflammation induced by AGEs and high-fat diets in vivo. PMID:19779136

  1. Skin autofluorescence, a measure of cumulative metabolic stress and advanced glycation end products, predicts mortality in hemodialysis patients.

    PubMed

    Meerwaldt, Robbert; Hartog, Jasper W L; Graaff, Reindert; Huisman, Roel J; Links, Thera P; den Hollander, Nynke C; Thorpe, Susan R; Baynes, John W; Navis, Gerjan; Gans, Rijk O B; Smit, Andries J

    2005-12-01

    Tissue advanced glycation end products (AGE) are a measure of cumulative metabolic stress and trigger cytokines driven inflammatory reactions. AGE are thought to contribute to the chronic complications of diabetes and ESRD. Tissue autofluorescence is related to the accumulation of AGE. Therefore, skin autofluorescence (AF) may provide prognostic information on mortality in hemodialysis (HD) patients. Skin AF was measured noninvasively with an AF reader at baseline in 109 HD patients. Overall and cardiovascular mortality was monitored prospectively during a period of 3 yr. The AF reader was validated against AGE contents in skin biopsies from 29 dialysis patients. Forty-two of the 109 (38.5%) HD patients died. Cox regression analysis showed that AF was an independent predictor of overall and cardiovascular mortality (for overall mortality odds ratio [OR] 3.9), as were pre-existing cardiovascular disease (CVD; OR 3.1), C-reactive protein (OR 1.1), and serum albumin (OR 0.3). Multivariate analysis revealed that 65% of the variance in AF could be attributed to the independent effects of age, dialysis and renal failure duration, presence of diabetes, triglycerides levels, and C-reactive protein. AF was also independently linked to the presence of CVD at baseline (OR 8.8; P < 0.001). AF correlated with collagen-linked fluorescence (r = 0.71, P < 0.001), pentosidine (r = 0.75, P < 0.001), and carboxy(m)ethyllysine (both r = 0.45, P < 0.01). Skin AF is a strong and independent predictor of mortality in ESRD. This supports a role for AGE as a contributor to mortality and CVD and warrants interventions specifically aimed at AGE accumulation.

  2. Skin autofluorescence relates to soluble receptor for advanced glycation end-products and albuminuria in diabetes mellitus.

    PubMed

    Skrha, J; Soupal, J; Loni Ekali, G; Prázný, M; Kalousová, M; Kvasnička, J; Landová, L; Zima, T; Skrha, J

    2013-01-01

    The aim of this study was to compare skin autofluorescence caused by advanced glycation end-products (AGEs) with biochemical markers of endothelial dysfunction and soluble receptor for AGEs (sRAGE) in patients with diabetes. Skin autofluorescence (AF) assessed by AGE-Reader was evaluated with sRAGE and other biochemical parameters in 88 patients with diabetes (47 Type 1/T1DM/ and 41 Type 2/T2DM/) and 20 controls. Skin AF was significantly higher in T1DM and T2DM in comparison to controls (2.39 ± 0.54, 2.63 ± 0.73 versus 1.96 ± 0.33 AU; P < 0.0001). Positive correlation of AF with sRAGE was detected in T1DM and T2DM (r = 0.37, P < 0.02 and r = 0.60, P < 0.0001), but not in controls. Significantly higher AF values were found in patients with positive albuminuria as compared to those with normal albuminuria. Similarly, higher AF was detected in patients with endothelial dysfunction expressed by vWF, ICAM-1, and VCAM-1. Multiple regression analysis revealed independent association of skin AF with age, sRAGE, and albumin-creatinine ratio in patients with diabetes (R (2) = 0.38). Our study confirms that AF is elevated in patients with diabetes, especially with positive albuminuria and endothelial dysfunction. The strong and independent relationship between AF and sRAGE supports the idea that AF may reflect AGEs/RAGE interactions. The exact mechanism remains to be established.

  3. Advanced Glycation End-Products Induce Apoptosis of Vascular Smooth Muscle Cells: A Mechanism for Vascular Calcification

    PubMed Central

    Koike, Sayo; Yano, Shozo; Tanaka, Sayuri; Sheikh, Abdullah M.; Nagai, Atsushi; Sugimoto, Toshitsugu

    2016-01-01

    Vascular calcification, especially medial artery calcification, is associated with cardiovascular death in patients with diabetes mellitus and chronic kidney disease (CKD). To determine the underlying mechanism of vascular calcification, we have demonstrated in our previous report that advanced glycation end-products (AGEs) stimulated calcium deposition in vascular smooth muscle cells (VSMCs) through excessive oxidative stress and phenotypic transition into osteoblastic cells. Since AGEs can induce apoptosis, in this study we investigated its role on VSMC apoptosis, focusing mainly on the underlying mechanisms. A rat VSMC line (A7r5) was cultured, and treated with glycolaldehyde-derived AGE-bovine serum albumin (AGE3-BSA). Apoptotic cells were identified by Terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) staining. To quantify apoptosis, an enzyme-linked immunosorbent assay (ELISA) for histone-complexed DNA fragments was employed. Real-time PCR was performed to determine the mRNA levels. Treatment of A7r5 cells with AGE3-BSA from 100 µg/mL concentration markedly increased apoptosis, which was suppressed by Nox inhibitors. AGE3-BSA significantly increased the mRNA expression of NAD(P)H oxidase components including Nox4 and p22phox, and these findings were confirmed by protein levels using immunofluorescence. Dihydroethidisum assay showed that compared with cBSA, AGE3-BSA increased reactive oxygen species level in A7r5 cells. Furthermore, AGE3-induced apoptosis was significantly inhibited by siRNA-mediated knockdown of Nox4 or p22phox. Double knockdown of Nox4 and p22phox showed a similar inhibitory effect on apoptosis as single gene silencing. Thus, our results demonstrated that NAD(P)H oxidase-derived oxidative stress are involved in AGEs-induced apoptosis of VSMCs. These findings might be important to understand the pathogenesis of vascular calcification in diabetes and CKD. PMID:27649164

  4. Advanced glycation end products suppress lysyl oxidase and induce bone collagen degradation in a rat model of renal osteodystrophy.

    PubMed

    Aoki, Chiharu; Uto, Kenta; Honda, Kazuho; Kato, Yoshiharu; Oda, Hideaki

    2013-11-01

    Renal osteodystrophy (ROD) is a major problem in patients with renal insufficiency. The present study was designed to elucidate the role of bone collagen changes and osteoblast differentiation in a rat model of ROD pathogenesis induced by adenine. Typical characteristics of renal failure, including increased serum urea nitrogen, creatinine, inorganic phosphorus, and intact parathyroid hormone levels, and decreased serum calcium and 1,25(OH)2D3 levels, were observed in adenine-induced rats. Micro-computed tomography analysis of the femur in adenine-induced rats showed decreased bone mineral density and osteoporotic changes, confirmed by the three-point bending test. The cancellous bone histomorphometric parameters of the tibia showed increased osteoblast number, decreased osteoclast surface with peritrabecular fibrosis, and increased osteoid tissue, indicating a severe mineralization disorder similar to clinical ROD. Scanning and transmission electron microscopy revealed irregular alignment and increased diameter of bone collagen fibrils in adenine-induced rats. Protein expression analysis showed greater accumulation of advanced glycation end products (AGEs) in peritrabecular osteoblasts of adenine-induced rats than in the controls. In contrast, suppressed expression of runt-related transcription factor 2, alkaline phosphatase, secreted phosphoprotein 1 (Spp1), and lysyl oxidase (Lox) mRNA levels, particularly the amount of active LOX protein, were observed. In in-vitro experiments, mineralizing MC3T3-E1 osteoblastic cells stimulated with AGE-modified bovine serum albumin had attenuated the expression of Spp1 mRNA levels and active LOX protein, with a decrease in extracellular nodules of mineralization. These observations provide clues to ROD pathogenesis, as they indicate that the suppression of osteoblast differentiation and decreased active LOX protein associated with accumulation of AGEs in osteoblasts caused structural abnormalities of bone collagen fibrils and

  5. Advanced Glycation End-Products Induce Apoptosis of Vascular Smooth Muscle Cells: A Mechanism for Vascular Calcification.

    PubMed

    Koike, Sayo; Yano, Shozo; Tanaka, Sayuri; Sheikh, Abdullah M; Nagai, Atsushi; Sugimoto, Toshitsugu

    2016-01-01

    Vascular calcification, especially medial artery calcification, is associated with cardiovascular death in patients with diabetes mellitus and chronic kidney disease (CKD). To determine the underlying mechanism of vascular calcification, we have demonstrated in our previous report that advanced glycation end-products (AGEs) stimulated calcium deposition in vascular smooth muscle cells (VSMCs) through excessive oxidative stress and phenotypic transition into osteoblastic cells. Since AGEs can induce apoptosis, in this study we investigated its role on VSMC apoptosis, focusing mainly on the underlying mechanisms. A rat VSMC line (A7r5) was cultured, and treated with glycolaldehyde-derived AGE-bovine serum albumin (AGE3-BSA). Apoptotic cells were identified by Terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) staining. To quantify apoptosis, an enzyme-linked immunosorbent assay (ELISA) for histone-complexed DNA fragments was employed. Real-time PCR was performed to determine the mRNA levels. Treatment of A7r5 cells with AGE3-BSA from 100 µg/mL concentration markedly increased apoptosis, which was suppressed by Nox inhibitors. AGE3-BSA significantly increased the mRNA expression of NAD(P)H oxidase components including Nox4 and p22(phox), and these findings were confirmed by protein levels using immunofluorescence. Dihydroethidisum assay showed that compared with cBSA, AGE3-BSA increased reactive oxygen species level in A7r5 cells. Furthermore, AGE3-induced apoptosis was significantly inhibited by siRNA-mediated knockdown of Nox4 or p22(phox). Double knockdown of Nox4 and p22(phox) showed a similar inhibitory effect on apoptosis as single gene silencing. Thus, our results demonstrated that NAD(P)H oxidase-derived oxidative stress are involved in AGEs-induced apoptosis of VSMCs. These findings might be important to understand the pathogenesis of vascular calcification in diabetes and CKD. PMID:27649164

  6. Advanced glycation end product Nε-carboxymethyllysine induces endothelial cell injury: the involvement of SHP-1-regulated VEGFR-2 dephosphorylation.

    PubMed

    Liu, Shing Hwa; Sheu, Wayne Huey Herng; Lee, Maw Rong; Lee, Wen Jane; Yi, Yu Chiao; Yang, Tzung Jie; Jen, Jen Fon; Pan, Hung Chuan; Shen, Chin Chang; Chen, Wen Bao; Tien, Hsing Ru; Sheu, Meei Ling

    2013-06-01

    N(ε)-carboxymethyllysine (CML), a major advanced glycation end product, plays a crucial role in diabetes-induced vascular injury. The roles of protein tyrosine phosphatases and vascular endothelial growth factor (VEGF) receptors in CML-related endothelial cell injury are still unclear. Human umbilical vein endothelial cells (HUVECs) are a commonly used human EC type. Here, we tested the hypothesis that NADPH oxidase/reactive oxygen species (ROS)-mediated SH2 domain-containing tyrosine phosphatase-1 (SHP-1) activation by CML inhibits the VEGF receptor-2 (VEGFR-2, KDR/Flk-1) activation, resulting in HUVEC injury. CML significantly inhibited cell proliferation and induced apoptosis and reduced VEGFR-2 activation in parallel with the increased SHP-1 protein expression and activity in HUVECs. Adding recombinant VEGF increased forward biological effects, which were attenuated by CML. The effects of CML on HUVECs were abolished by SHP-1 siRNA transfection. Exposure of HUVECs to CML also remarkably escalated the integration of SHP-1 with VEGFR-2. Consistently, SHP-1 siRNA transfection and pharmacological inhibitors could block this interaction and elevating [(3)H]thymidine incorporation. CML also markedly activated the NADPH oxidase and ROS production. The CML-increased SHP-1 activity in HUVECs was effectively attenuated by antioxidants. Moreover, the immunohistochemical staining of SHP-1 and CML was increased, but phospho-VEGFR-2 staining was decreased in the aortic endothelium of streptozotocin-induced and high-fat diet-induced diabetic mice. We conclude that a pathway of tyrosine phosphatase SHP-1-regulated VEGFR-2 dephosphorylation through NADPH oxidase-derived ROS is involved in the CML-triggered endothelial cell dysfunction/injury. These findings suggest new insights into the development of therapeutic approaches to reduce diabetic vascular complications.

  7. Curcumin inhibits advanced glycation end product-induced oxidative stress and inflammatory responses in endothelial cell damage via trapping methylglyoxal

    PubMed Central

    SUN, YAN PING; GU, JUN FEI; TAN, XIAO BIN; WANG, CHUN FEI; JIA, XIAO BIN; FENG, LIANG; LIU, JI PING

    2016-01-01

    Methylglyoxal (MGO)-induced carbonyl stress and pro-inflammatory responses have been suggested to contribute to endothelial dysfunction. Curcumin (Cur), a polyphenolic compound from Curcuma longa L., may protect endothelial cells against carbonyl stress-induced damage by trapping dicarbonyl compounds such as MGO. However, Cur-MGO adducts have not been studied in depth to date and it remains to be known whether Cur-MGO adducts are able to attenuate endothelial damage by trapping MGO. In the present study, 1,2-diaminobenzene was reacted with MGO to ensure the reliability of the reaction system. Cur was demonstrated to trap MGO at a 1:1 ratio to form adducts 1, 2 and 3 within 720 min. The structures of these adducts were identified by high-performance liquid chromatography/electrospray ionization tandem mass spectrometry. The kinetic curves of Cur (10−7, 10−6 and 10−5 M) were measured from 0–168 h by fluorescent intensity. Cur significantly inhibited the formation of advanced glycation end products (AGEs). The differences in oxidative damage and the levels of pro-inflammatory cytokines following MGO + HSA or Cur-MGO treatment were investigated in human umbilical vein endothelial cells (HUVECs). Exposure of HUVECs to the Cur-MGO reaction adducts significantly reduced the intracellular ROS levels and improved cell viability compared with MGO alone. Furthermore, there was a significant reduction in the expression levels of transforming growth factor-β1 and intercellular adhesion molecule-1 following treatment with Cur-MGO adducts compared with MGO alone. These results provide further evidence that the trapping of MGO by Cur inhibits the formation of AGEs. The current study indicates that the protective effect of Cur on carbonyl stress and pro-inflammatory responses in endothelial damage occurs via the trapping of MGO. PMID:26718010

  8. Carboxymethyl lysine, an advanced glycation end-product, and incident diabetes: a case-cohort analysis of the ARIC Study

    PubMed Central

    Luft, V. C.; Duncan, B. B.; Schmidt, M. I.; Chambless, L. E.; Pankow, J. S.; Hoogeveen, R. C.; Couper, D. J.; Heiss, G.

    2016-01-01

    Aims To verify whether elevated fasting levels of circulating carboxymethyl lysine (CML), an advanced glycation end-product (AGE), predict the development of diabetes in middle-age adults. Methods Using a stratified case-cohort design, we followed 543 middle-aged individuals who developed diabetes and 514 who did not over a median 9 years in the Atherosclerosis Risk in Communities Study. Weighted Cox proportional hazards analyses were used to account for the design. Results In weighted analyses, correlation between CML levels and anthropometric, inflammatory or metabolic variables was minimal (Pearson correlations usually <0.10). CML, when modelled as a continuous variable and after adjustment for age, sex, race, centre, parental history of diabetes, body mass index, waist-to-hip ratio, NEFA, oxidized LDL-cholesterol, glomerular filtration rate, smoking, an inflammation score, adiponectin, leptin, insulin, and glucose levels, was associated with increased risk of diabetes (HR=1.35; 95% CI 1.09 – 1.67, for each 100 ng/mL CML increment). Baseline glucose level and race each modified the association (p<0.05 for interaction), which was present only among those with impaired fasting glucose (≥5.6 mmol/l, HR=1.61, 95%CI 1.26 – 2.05) and among whites (HR=1.50, 95%CI 1.13 – 1.99). Conclusions Elevated fasting CML, after adjustment for multiple risk factors for diabetes, predicts the development of incident diabetes, the association being present among those with impaired fasting glucose and in whites. These prospective findings suggest that AGE might play a role in the development of diabetes. PMID:26359784

  9. Skin autofluorescence, a measure of cumulative metabolic stress and advanced glycation end products, predicts mortality in hemodialysis patients.

    PubMed

    Meerwaldt, Robbert; Hartog, Jasper W L; Graaff, Reindert; Huisman, Roel J; Links, Thera P; den Hollander, Nynke C; Thorpe, Susan R; Baynes, John W; Navis, Gerjan; Gans, Rijk O B; Smit, Andries J

    2005-12-01

    Tissue advanced glycation end products (AGE) are a measure of cumulative metabolic stress and trigger cytokines driven inflammatory reactions. AGE are thought to contribute to the chronic complications of diabetes and ESRD. Tissue autofluorescence is related to the accumulation of AGE. Therefore, skin autofluorescence (AF) may provide prognostic information on mortality in hemodialysis (HD) patients. Skin AF was measured noninvasively with an AF reader at baseline in 109 HD patients. Overall and cardiovascular mortality was monitored prospectively during a period of 3 yr. The AF reader was validated against AGE contents in skin biopsies from 29 dialysis patients. Forty-two of the 109 (38.5%) HD patients died. Cox regression analysis showed that AF was an independent predictor of overall and cardiovascular mortality (for overall mortality odds ratio [OR] 3.9), as were pre-existing cardiovascular disease (CVD; OR 3.1), C-reactive protein (OR 1.1), and serum albumin (OR 0.3). Multivariate analysis revealed that 65% of the variance in AF could be attributed to the independent effects of age, dialysis and renal failure duration, presence of diabetes, triglycerides levels, and C-reactive protein. AF was also independently linked to the presence of CVD at baseline (OR 8.8; P < 0.001). AF correlated with collagen-linked fluorescence (r = 0.71, P < 0.001), pentosidine (r = 0.75, P < 0.001), and carboxy(m)ethyllysine (both r = 0.45, P < 0.01). Skin AF is a strong and independent predictor of mortality in ESRD. This supports a role for AGE as a contributor to mortality and CVD and warrants interventions specifically aimed at AGE accumulation. PMID:16280473

  10. Skin autofluorescence relates to soluble receptor for advanced glycation end-products and albuminuria in diabetes mellitus.

    PubMed

    Skrha, J; Soupal, J; Loni Ekali, G; Prázný, M; Kalousová, M; Kvasnička, J; Landová, L; Zima, T; Skrha, J

    2013-01-01

    The aim of this study was to compare skin autofluorescence caused by advanced glycation end-products (AGEs) with biochemical markers of endothelial dysfunction and soluble receptor for AGEs (sRAGE) in patients with diabetes. Skin autofluorescence (AF) assessed by AGE-Reader was evaluated with sRAGE and other biochemical parameters in 88 patients with diabetes (47 Type 1/T1DM/ and 41 Type 2/T2DM/) and 20 controls. Skin AF was significantly higher in T1DM and T2DM in comparison to controls (2.39 ± 0.54, 2.63 ± 0.73 versus 1.96 ± 0.33 AU; P < 0.0001). Positive correlation of AF with sRAGE was detected in T1DM and T2DM (r = 0.37, P < 0.02 and r = 0.60, P < 0.0001), but not in controls. Significantly higher AF values were found in patients with positive albuminuria as compared to those with normal albuminuria. Similarly, higher AF was detected in patients with endothelial dysfunction expressed by vWF, ICAM-1, and VCAM-1. Multiple regression analysis revealed independent association of skin AF with age, sRAGE, and albumin-creatinine ratio in patients with diabetes (R (2) = 0.38). Our study confirms that AF is elevated in patients with diabetes, especially with positive albuminuria and endothelial dysfunction. The strong and independent relationship between AF and sRAGE supports the idea that AF may reflect AGEs/RAGE interactions. The exact mechanism remains to be established. PMID:23671885

  11. 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

  12. 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

  13. Detection of galectin-3 and localization of advanced glycation end products (AGE) in human chronic skin wounds.

    PubMed

    Pepe, Daniel; Elliott, Christopher G; Forbes, Thomas L; Hamilton, Douglas W

    2014-02-01

    The matricellular protein galectin-3 (Gal-3) is upregulated in excisional skin repair in rats where it has been shown to modulate the inflammatory phase of repair. Recent research into kidney pathology has implicated Gal-3 as a receptor for advanced glycation end products (AGE), resulting in the binding and clearance of these molecules. AGEs are thought to contribute to defective skin repair in diabetic patients as well as a result of the normal aging process. However, the distribution and localization of Gal-3 and AGEs has never been performed in human chronic skin wound tissue. Using immunohistochemistry, the localization of Gal-3 and AGEs in tissue isolated from chronic wounds and non-involved skin from the same patient was investigated. Of the 16 patients from which tissue was isolated, 13 had type II diabetes, one had type I diabetes and 2 patients without diabetes were also examined. In non-involved dermis, Gal-3 was detected strongly in the epidermis and in the vasculature. However, at the wound edge and in the wound bed, the level of Gal-3 labelling was greatly reduced in both the epidermis and vasculature. Labelling of serial sections for Gal-3 and AGE demonstrated that where Gal-3 immunoreactivity is reduced in the epidermis and vasculature, there is a concomitant increase in the level of AGE staining. Interestingly, similar labelling patterns were evident in diabetic and non-diabetic patients. The results from our study demonstrate an inverse correlation between Gal-3 and AGEs localization, suggesting that Gal-3 may protect against accumulation of AGEs in wound healing.

  14. 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

  15. Dietary advanced glycation end products restriction diminishes inflammation markers and oxidative stress in patients with type 2 diabetes mellitus

    PubMed Central

    Luévano-Contreras, Claudia; Garay-Sevilla, Ma. Eugenia; Wrobel, Kazimierz; Malacara, Juan M.; Wrobel, Katarzyna

    2013-01-01

    The augmented consumption of dietary advanced glycation end products (dAGEs) has been associated with increased oxidative stress and inflammation, however, there is insufficient information over the effect on insulin resistance. The objective of the present study is to investigate the effect of dAGEs restriction on tumor necrosis factor-α (TNF-α), malondialdehyde, C-reactive protein (CRP), and insulin resistance in DM2 patients. We carried out a randomized 6 weeks prospective study in two groups of patients: subjects with a standard diet (n = 13), vs low dAGEs (n = 13). At the beginning and the end of study, we collected anthropometric measurements, and values of circulating glucose, HbA1c, lipids, insulin, serum AGEs, CRP, TNF-α and malondialdehyde. Anthropometric measurements, glucose, and lipids were similar in both groups at base line and at the end of the study. Estimation of basal dAGEs was similar in both groups; after 6 weeks it was unchanged in the standard group but in the low dAGEs group decreased by 44% (p<0.0002). Changes in TNF-α levels were different under standard diet (12.5 ± 14.7) as compared with low dAGEs (−18.36 ± 17.1, p<0.00001); changes in malondialdehyde were different in the respective groups (2.0 ± 2.61 and −0.83 ± 2.0, p<0.005) no changes were found for insulin levels or HOMA-IR. In conclusion, The dAGEs restriction decreased significantly TNF-α and malondialdehyde levels. PMID:23341693

  16. Dietary advanced glycation end products restriction diminishes inflammation markers and oxidative stress in patients with type 2 diabetes mellitus.

    PubMed

    Luévano-Contreras, Claudia; Garay-Sevilla, Ma Eugenia; Wrobel, Kazimierz; Malacara, Juan M; Wrobel, Katarzyna

    2013-01-01

    The augmented consumption of dietary advanced glycation end products (dAGEs) has been associated with increased oxidative stress and inflammation, however, there is insufficient information over the effect on insulin resistance. The objective of the present study is to investigate the effect of dAGEs restriction on tumor necrosis factor-α (TNF-α), malondialdehyde, C-reactive protein (CRP), and insulin resistance in DM2 patients. We carried out a randomized 6 weeks prospective study in two groups of patients: subjects with a standard diet (n = 13), vs low dAGEs (n = 13). At the beginning and the end of study, we collected anthropometric measurements, and values of circulating glucose, HbA1c, lipids, insulin, serum AGEs, CRP, TNF-α and malondialdehyde. Anthropometric measurements, glucose, and lipids were similar in both groups at base line and at the end of the study. Estimation of basal dAGEs was similar in both groups; after 6 weeks it was unchanged in the standard group but in the low dAGEs group decreased by 44% (p<0.0002). Changes in TNF-α levels were different under standard diet (12.5 ± 14.7) as compared with low dAGEs (-18.36 ± 17.1, p<0.00001); changes in malondialdehyde were different in the respective groups (2.0 ± 2.61 and -0.83 ± 2.0, p<0.005) no changes were found for insulin levels or HOMA-IR. In conclusion, The dAGEs restriction decreased significantly TNF-α and malondialdehyde levels.

  17. 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

  18. Toxic action of advanced glycation end products on cultured retinal capillary pericytes and endothelial cells: relevance to diabetic retinopathy.

    PubMed

    Chibber, R; Molinatti, P A; Rosatto, N; Lambourne, B; Kohner, E M

    1997-02-01

    The toxic effects of advanced glycation end products (AGEs) on bovine retinal capillary pericytes (BRP) and endothelial cells (BREC) were studied. AGE-modified bovine serum albumin (AGE-BSA) was toxic to BRP. At a concentration of 500 micrograms/ml it reduced the BRP number to 48 +/- 3% (p < 0.05) of untreated controls, as determined by cell counting with haemocytometer. AGE-BSA was also toxic to bovine aortic endothelial cells (BAEC) reducing cell number to 84 +/- 3.1% of untreated controls. Under similar conditions, low concentrations (62.5 micrograms/ml) of AGE-BSA were mitogenic to BREC increasing the cell proliferation to 156 +/- 11% (p < 0.05) above that of untreated controls. At a higher dose of 500 micrograms/ml AGE-BSA decreased the proliferation of BREC to 85 +/- 6% of untreated controls. Immunoblot analysis demonstrated that BRP and BREC express the p60 AGE-receptor. Retinal capillary bed from the human also stained positively for the p60 AGE-receptor. Addition of 0.25 micrograms/ml of p60 AGE-receptor antibody was able to block the effects of AGE-BSA on BRP and BREC. The level of binding of [125I]-labelled AGE-BSA to the cell surface was small but significant among the three cell types. There was also an increase in the internalized pool of radioligand in BRP and BREC but this was very much lower than in BAEC. In all the cell types the internalized pool of [125I]-labelled AGE-BSA was much larger than the amount associated with the cell surface. Degradation products were not detected in the media over the 24-h incubation of the cells with [125I]AGE-BSA. The binding of [125I]-labelled AGE-BSA to the cell surface was prevented by the addition of p60 AGE-receptor. These results suggest that the interaction of AGE-modified proteins with the membrane-bound AGE-receptor may play an important role in the pathogenesis of diabetic retinopathy.

  19. Advanced glycation end products and their circulating receptors predict cardiovascular disease mortality in older community-dwelling women

    PubMed Central

    Semba, Richard D.; Ferrucci, Luigi; Sun, Kai; Beck, Justine; Dalal, Mansi; Varadhan, Ravi; Walston, Jeremy; Guralnik, Jack M.; Fried, Linda P.

    2008-01-01

    Objective To characterize the relationship between advanced glycation end products (AGEs) and circulating receptors for AGEs (RAGE) with cardiovascular disease mortality. Methods The relationships between serum AGEs, total RAGE (sRAGE), and endogenous secretory RAGE (esRAGE), and mortality were characterized in 559 community-dwelling women, ≥65 years, in Baltimore, Maryland. Results During 4.5 years of follow-up, 123 (22%) women died, of whom 54 died with cardiovascular disease. The measure of serum AGEs was carboxymethyl-lysine (CML), a dominant AGE. Serum CML predicted cardiovascular disease mortality (Hazards Ratio [H.R.] for highest versus lower three quartiles 1.94, 95% Confidence Interval [C.I.] 1.08-3.48, P = 0.026), after adjusting for age, race, body mass index, and renal insufficiency. Serum sRAGE (ng/mL) and esRAGE (ng/mL) predicted cardiovascular disease mortality (H.R. per 1 Standard Deviation [S.D.] 1.27, 95% C.I. 0.98-1.65, P = 0.07; H.R. 1.28, 95% C.I. 1.02-1.63, P = 0.03), after adjusting for the same covariates. Among non-diabetic women, serum CML, sRAGE, and esRAGE, respectively, predicted cardiovascular disease mortality (H.R. for highest versus lower three quartiles, 2.29, 95% C.I. 1.21-4.34, P = 0.01; H.R. per 1 S.D., 1.24, 95% C.I. 0.92-1.65, P = 0.16; H.R. per 1 S.D. 1.45, 95% C.I. 1.08-1.93, P = 0.01), after adjusting for the same covariates. Conclusions High circulating AGEs and RAGE predict cardiovascular disease mortality among older community-dwelling women. AGEs are a potential target for interventions, as serum AGEs can be lowered by change in dietary pattern and pharmacological treatment. PMID:19448391

  20. 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

  1. Advanced oxidation protein products induce chondrocyte apoptosis via receptor for advanced glycation end products-mediated, redox-dependent intrinsic apoptosis pathway.

    PubMed

    Wu, Qian; Zhong, Zhao-Ming; Zhu, Si-Yuan; Liao, Cong-Rui; Pan, Ying; Zeng, Ji-Huan; Zheng, Shuai; Ding, Ruo-Ting; Lin, Qing-Song; Ye, Qing; Ye, Wen-Bin; Li, Wei; Chen, Jian-Ting

    2016-01-01

    Pro-inflammatory cytokine-induced chondrocyte apoptosis is a primary cause of cartilage destruction in the progression of rheumatoid arthritis (RA). Advanced oxidation protein products (AOPPs), a novel pro-inflammatory mediator, have been confirmed to accumulate in patients with RA. However, the effect of AOPPs accumulation on chondrocyte apoptosis and the associated cellular mechanisms remains unclear. The present study demonstrated that the plasma formation of AOPPs was enhanced in RA rats compared with normal. Then, chondrocyte were treated with AOPPs-modified rat serum albumin (AOPPs-RSA) in vitro. Exposure of chondrocyte to AOPPs activated nicotinamide adenine dinucleotide phosphate (NADPH) oxidase and increased expression of NADPH oxidase subunits, which was mediated by receptor for advanced glycation end products (RAGE), but not scavenger receptor CD36. Moreover, AOPPs challenge triggered NADPH oxidase-dependent ROS generation which induced mitochondrial dysfunction and endoplasmic reticulum stress resulted in activation of caspase family that eventually lead to apoptosis. Lastly, blockade of RAGE, instead of CD36, largely attenuated these signals. Our study demonstrated first time that AOPPs induce chondrocyte apoptosis via RAGE-mediated and redox-dependent intrinsic apoptosis pathway in vitro. These data implicates that AOPPs may represent a novel pathogenic factor that contributes to RA progression. Targeting AOPPs-triggered cellular mechanisms might emerge as a promising therapeutic option for patients with RA.

  2. S100A12 and soluble receptor for advanced glycation end products levels during human severe sepsis.

    PubMed

    Achouiti, Ahmed; Föll, Dirk; Vogl, Thomas; van Till, Jan W O; Laterre, Pierre-François; Dugernier, Thierry; Wittebole, Xavier; Boermeester, Marja A; Roth, Johannes; van der Poll, Tom; van Zoelen, Marieke A D

    2013-09-01

    S100A12 is highly expressed, and serum levels correlate with individual disease activity in patients with inflammatory diseases. We here sought to determine the extent of S100A12 release and its soluble high-affinity receptor for advanced glycation end products (sRAGE) in patients with severe sepsis stratified to the three most common infectious sources (lungs, abdomen, and urinary tract) and to determine S100A12 and sRAGE concentrations at the site of infection during peritonitis. Two patient populations were studied: (a) 51 patients with sepsis due to (i) peritonitis (n = 12), (ii) pneumonia (n = 29), or (iii) urinary tract infection (n = 10); and (b) 17 patients with peritonitis. In addition, eight healthy humans were studied after intravenous injection of lipopolysaccharide (4 ng/kg). Compared with healthy volunteers, patients with severe sepsis displayed increased circulating S100A12 concentrations at day 0 (591.2 ± 101.0 vs. 106.2 ± 15.6 ng/mL [control subjects], P < 0.0001) and at day 3 (637.2 ± 111.2 vs. 106.2 ± 15.6 ng/mL [control subjects], P < 0.0001). All three severe sepsis subgroups had elevated serum S100A12 concentrations at both time points (sepsis due to [i] peritonitis [393.5 ± 89.9 at day 0 and 337.9 ± 97.2 at day 3 vs. 106.2 ± 15.6 ng/mL, control subjects, P < 0.005 and P < 0.05, respectively]; [ii] pneumonia [716.9 ± 167.0 at day 0 and 787.5 ± 164.7 at day 3 vs. 106.2 ± 15.6 ng/mL, control subjects, both P < 0.0001]; and [iii] urinary tract infection [464.2 ± 115.6 at day 0 and 545.6 ± 254.9 at day 3 vs. 106.2 ± 15.6 ng/mL, control subjects, P < 0.0001 and P < 0.05, respectively]). Remarkably, patients with sepsis due to pneumonia had the highest S100A12 levels (716.9 ± 167.0 and 787.5 ± 164.7 ng/mL at days 0 and 3, respectively). S100A12 levels were not correlated to either Acute Physiology and Chronic Health Evaluation II scores (r = -0.185, P = 0.19) or Sepsis-Related Organ Failure Assessment scores (r = -0.194, P = 0

  3. 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.

  4. Receptor for Advanced Glycation End Products (RAGE) Prevents Endothelial Cell Membrane Resealing and Regulates F-actin Remodeling in a β-Catenin-dependent Manner*

    PubMed Central

    Xiong, Fei; Leonov, Sergey; Howard, Amber Cyan; Xiong, Shan; Zhang, Bin; Mei, Lin; McNeil, Paul; Simon, Sylvia; Xiong, Wen-Cheng

    2011-01-01

    Receptor for advanced glycation end products (RAGE), an immunoglobin superfamily cell surface receptor, contributes to the vascular pathology associated with multiple disorders, including Alzheimer disease (AD), diabetic complications, and inflammatory conditions. However, the underlying mechanisms remain largely unclear. Here, using the human umbilical vein endothelial cell line (ECV-304) expressing human RAGE, we report that RAGE expression leads to an altered F-actin organization and impaired membrane resealing. To investigate the underlying mechanisms, we showed that RAGE expression increases β-catenin level, which decreases F-actin stress fibers and attenuates plasma membrane resealing. These results thus suggest a negative function for RAGE in endothelial cell membrane repair and reveal a new mechanism underlying RAGE regulation of F-actin remodeling and membrane resealing. PMID:21844192

  5. Metformin Inhibits Advanced Glycation End Products-Induced Inflammatory Response in Murine Macrophages Partly through AMPK Activation and RAGE/NFκB Pathway Suppression

    PubMed Central

    Zhou, Zhong'e; Tang, Yong; Chen, Chengjun; Lu, Yi; Liu, Liang

    2016-01-01

    Advanced glycation end products (AGEs) are major inflammatory mediators in diabetes, affecting atherosclerosis progression via macrophages. Metformin slows diabetic atherosclerosis progression through mechanisms that remain to be fully elucidated. The present study of murine bone marrow derived macrophages showed that (1) AGEs enhanced proinflammatory cytokines (interleukin-1β (IL-1β), IL-6, and tumor necrosis factor-α (TNF-α)) mRNA expression, RAGE expression, and NFκB activation; (2) metformin pretreatment inhibited AGEs effects and AGEs-induced cluster designation 86 (CD86) (M1 marker) expression, while promoting CD206 (M2 marker) surface expression and anti-inflammatory cytokine (IL-10) mRNA expression; and (3) the AMPK inhibitor, Compound C, attenuated metformin effects. In conclusion, metformin inhibits AGEs-induced inflammatory response in murine macrophages partly through AMPK activation and RAGE/NFκB pathway suppression. PMID:27761470

  6. Kinetics of advanced glycation end products formation on bovine serum albumin with various reducing sugars and dicarbonyl compounds in equimolar ratios.

    PubMed

    Luers, Lars; Rysiewski, Karolina; Dumpitak, Christian; Birkmann, Eva

    2012-04-01

    Reducing sugars and reactive dicarbonyl compounds play a major role in glycation of proteins in vivo. Glycation of proteins is the first step in of a nonenzymatic reaction, resulting in advanced glycation end products (AGEs). AGEs can inactivate proteins or modify their biological activities. Therefore, it is important to understand the mechanism of AGE formation. Here, we systematically analyzed the kinetics of AGE formation in vitro by fluorescence and absorption measurements utilizing a microplate reader system and bovine serum albumin (BSA) as a model protein. Comparing different concentrations of BSA, we applied various reducing sugars and reactive dicarbonyl compounds as AGE-inducing agents at different concentrations. In summary, this experimental setup enabled us to measure the kinetics of AGE formation in an efficient and defined way.

  7. A significant inhibitory effect on advanced glycation end product formation by catechin as the major metabolite of lotus seedpod oligomeric procyanidins.

    PubMed

    Wu, Qian; Li, Shuyi; Li, Xiaopeng; Fu, Xiaoyan; Sui, Yong; Guo, Tingting; Xie, Bijun; Sun, Zhida

    2014-08-01

    Several lines of evidence suggested that B-type procyanidin oligomers from lotus seedpod (LSOPC) may effectively modulate the formation of advanced glycation end products (AGEs). In vivo, LSOPC is metabolized by intestinal flora to become various kinds of phenolic compounds that possess potent antioxidant activities. However, few reports of the absorption and metabolism of LSOPC have been revealed. In the present study, rats were orally administered with LSOPC at a dose of 300 mg/kg body weight. The metabolites of LSOPC in urine were elucidated by HPLC-MS/MS analysis 24 h post-administration. Eight major metabolites were significantly increased by the administration of 300 mg/kg of LSOPC (p < 0.01). The anti-glycative activity of LSOPC and its metabolites were investigated. The results showed that LSOPC and catechin had greater anti-glycative activities than other metabolites, which were positively correlated to their carbonyl scavenging activities and antioxidant capacities. PMID:25123249

  8. Kinetics of advanced glycation end products formation on bovine serum albumin with various reducing sugars and dicarbonyl compounds in equimolar ratios.

    PubMed

    Luers, Lars; Rysiewski, Karolina; Dumpitak, Christian; Birkmann, Eva

    2012-04-01

    Reducing sugars and reactive dicarbonyl compounds play a major role in glycation of proteins in vivo. Glycation of proteins is the first step in of a nonenzymatic reaction, resulting in advanced glycation end products (AGEs). AGEs can inactivate proteins or modify their biological activities. Therefore, it is important to understand the mechanism of AGE formation. Here, we systematically analyzed the kinetics of AGE formation in vitro by fluorescence and absorption measurements utilizing a microplate reader system and bovine serum albumin (BSA) as a model protein. Comparing different concentrations of BSA, we applied various reducing sugars and reactive dicarbonyl compounds as AGE-inducing agents at different concentrations. In summary, this experimental setup enabled us to measure the kinetics of AGE formation in an efficient and defined way. PMID:22533432

  9. A significant inhibitory effect on advanced glycation end product formation by catechin as the major metabolite of lotus seedpod oligomeric procyanidins.

    PubMed

    Wu, Qian; Li, Shuyi; Li, Xiaopeng; Fu, Xiaoyan; Sui, Yong; Guo, Tingting; Xie, Bijun; Sun, Zhida

    2014-08-13

    Several lines of evidence suggested that B-type procyanidin oligomers from lotus seedpod (LSOPC) may effectively modulate the formation of advanced glycation end products (AGEs). In vivo, LSOPC is metabolized by intestinal flora to become various kinds of phenolic compounds that possess potent antioxidant activities. However, few reports of the absorption and metabolism of LSOPC have been revealed. In the present study, rats were orally administered with LSOPC at a dose of 300 mg/kg body weight. The metabolites of LSOPC in urine were elucidated by HPLC-MS/MS analysis 24 h post-administration. Eight major metabolites were significantly increased by the administration of 300 mg/kg of LSOPC (p < 0.01). The anti-glycative activity of LSOPC and its metabolites were investigated. The results showed that LSOPC and catechin had greater anti-glycative activities than other metabolites, which were positively correlated to their carbonyl scavenging activities and antioxidant capacities.

  10. 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

  11. Soluble Forms and Ligands of the Receptor for Advanced Glycation End-Products in Patients with Acute Respiratory Distress Syndrome: An Observational Prospective Study

    PubMed Central

    Jabaudon, Matthieu; Blondonnet, Raiko; Roszyk, Laurence; Pereira, Bruno; Guérin, Renaud; Perbet, Sébastien; Cayot, Sophie; Bouvier, Damien; Blanchon, Loic; Sapin, Vincent; Constantin, Jean-Michel

    2015-01-01

    Background The main soluble form of the receptor for advanced glycation end-products (sRAGE) is elevated during acute respiratory distress syndrome (ARDS). However other RAGE isoforms and multiple ligands have been poorly reported in the clinical setting, and their respective contribution to RAGE activation during ARDS remains unclear. Our goal was therefore to describe main RAGE isoforms and ligands levels during ARDS. Methods 30 ARDS patients and 30 mechanically ventilated controls were prospectively included in this monocenter observational study. Arterial, superior vena cava and alveolar fluid levels of sRAGE, endogenous-secretory RAGE (esRAGE), high mobility group box-1 protein (HMGB1), S100A12 and advanced glycation end-products (AGEs) were measured in duplicate ELISA on day 0, day 3 and day 6. In patients with ARDS, baseline lung morphology was assessed with computed tomography. Results ARDS patients had higher arterial, central venous and alveolar levels of sRAGE, HMGB1 and S100A12, but lower levels of esRAGE and AGEs, than controls. Baseline arterial sRAGE, HMGB1 and S100A12 were correlated with nonfocal ARDS (AUC 0.79, 0.65 and 0.63, respectively). Baseline arterial sRAGE, esRAGE, S100A12 and AGEs were associated with severity as assessed by PaO2/FiO2. Conclusions This is the first kinetics study of levels of RAGE main isoforms and ligands during ARDS. Elevated sRAGE, HMGB1 and S100A12, with decreased esRAGE and AGEs, were found to distinguish patients with ARDS from those without. Our findings should prompt future studies aimed at elucidating RAGE/HMGB1/S100A12 axis involvement in ARDS. Trial Registration clinicaltrials.gov Identifier: NCT01270295. PMID:26274928

  12. 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

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

    PubMed

    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.

  14. Albumin-derived advanced glycation end-products trigger the disruption of the vascular endothelial cadherin complex in cultured human and murine endothelial cells.

    PubMed Central

    Otero, K; Martínez, F; Beltrán, A; González, D; Herrera, B; Quintero, G; Delgado, R; Rojas, A

    2001-01-01

    Endothelial cell (EC) junctions regulate in large part the integrity and barrier function of the vascular endothelium. Advanced glycation end-products (AGEs), the irreversibly formed reactive derivatives of non-enzymic glucose-protein condensation reactions, are strongly implicated in endothelial dysfunction that distinguishes diabetes- and aging-associated vascular complications. The aim of the present study was to determine whether AGEs affect EC lateral junction proteins, with particular regard to the vascular endothelial cadherin (VE-cadherin) complex. Our results indicate that AGE-modified BSA (AGE-BSA), a prototype of advanced glycated proteins, disrupts the VE-cadherin complex when administered to ECs. AGE-BSA, but not unmodified BSA, was found to induce decreases in the levels of VE-cadherin, beta-catenin and gamma-catenin in the complex and in total cell extracts, as well as a marked reduction in the amount of VE-cadherin present at the cell surface. In contrast, the level of platelet endothelial cell adhesion molecule-1 (PECAM-1), which is located at lateral junctions, was not altered. Supplementation of the cellular antioxidative defences abolished these effects. Finally, the loss of components of the VE-cadherin complex was correlated with increases in vascular permeability and in EC migration. These findings suggest that some of the AGE-induced biological effects on the endothelium could be mediated, at least in part, by the weakening of intercellular contacts caused by decreases in the amount of VE-cadherin present. PMID:11672430

  15. 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.

  16. 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

  17. 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

  18. Advanced glycation end product-induced astrocytic differentiation of cultured neurospheres through inhibition of Notch-Hes1 pathway-mediated neurogenesis.

    PubMed

    Guo, Yijing; Wang, Pin; Sun, Haixia; Cai, Rongrong; Xia, Wenqing; Wang, Shaohua

    2014-01-01

    This study aims to investigate the roles of the Notch-Hes1 pathway in the advanced glycation end product (AGE)-mediated differentiation of neural stem cells (NSCs). We prepared pLentiLox3.7 lentiviral vectors that express short hairpin RNA (shRNA) against Notch1 and transfected it into NSCs. Cell differentiation was analyzed under confocal laser-scanning microscopy. The percentage of neurons and astrocytes was quantified by normalizing the total number of TUJ1+ (Neuron-specific class III β-tubulin) and GFAP+ (Glial fibrillary acidic protein) cells to the total number of Hoechst 33342-labeled cell nuclei. The protein and gene expression of Notch-Hes1 pathway components was examined via western blot analysis and real-time PCR. After 1 week of incubation, we found that AGE-bovine serum albumin (BSA) (400 μg/mL) induced the astrocytic differentiation of cultured neurospheres and inhibited neuronal formation. The expression of Notch-Hes1 pathway components was upregulated in the cells in the AGE-BSA culture medium. Immunoblot analysis indicated that shRNA silencing of Notch1 expression in NSCs significantly increases neurogenesis and suppresses astrocytic differentiation in NSCs incubated with AGE-BSA. AGEs promote the astrocytic differentiation of cultured neurospheres by inhibiting neurogenesis through the Notch-Hes1 pathway, providing a potential therapeutic target for hyperglycemia-related cognitive deficits.

  19. Heparan Sulfate Is Essential for High Mobility Group Protein 1 (HMGB1) Signaling by the Receptor for Advanced Glycation End Products (RAGE)*

    PubMed Central

    Xu, Ding; Young, Jeffrey; Song, Danyin; Esko, Jeffrey D.

    2011-01-01

    In a proteomic search for heparan sulfate-binding proteins on monocytes, we identified HMGB1 (high mobility group protein B1). The extracellular role of HMGB1 as a cytokine has been studied intensively and shown to be important as a danger-associated molecular pattern protein. Here, we report that the activity of HMGB1 depends on heparan sulfate. Binding and competition studies demonstrate that HMGB1 interacts with CHO and endothelial cell heparan sulfate. By site-directed mutagenesis, we identified a loop region that connects the A-box and B-box domains of HMGB1 as responsible for heparan sulfate binding. HMGB1-induced Erk1/2 and p38 phosphorylation is abolished when endothelial heparan sulfate is removed or blocked pharmacologically, resulting in decreased HMGB1-induced endothelial sprouting. However, mutated HMGB1 that lacks the heparan sulfate-binding site retained its signaling activity. We show the major receptor for HMGB1, receptor for advanced glycation end products (RAGE), also binds to heparan sulfate and that RAGE and heparan sulfate forms a complex. Our data establishes that the functional receptor for HMGB1 consists of a complex of RAGE and cell surface heparan sulfate. PMID:21990362

  20. Receptor for advanced glycation end products plays a more important role in cellular survival than in neurite outgrowth during retinoic acid-induced differentiation of neuroblastoma cells.

    PubMed

    Sajithlal, Gangadharan; Huttunen, Henri; Rauvala, Heikki; Munch, Gerald

    2002-03-01

    The receptor for advanced glycation end products (RAGE), a member of the immunoglobulin superfamily, is known to interact with amphoterin. This interaction has been proposed to play a role in neurite outgrowth and process elongation during neurodifferentiation. However, there is as yet no direct evidence of the relevance of this pathway to neurodifferentiation under physiological conditions. In this study we have investigated a possible role of RAGE and amphoterin in the retinoic acid-induced differentiation of neuroblastoma cells. The functional inactivation of RAGE by dominant negative and antisense strategies showed that RAGE is not required for process outgrowth or differentiation, although overexpression of RAGE accelerates the elongation of neuritic processes. Using the antisense strategy, amphoterin was shown to be essential for process outgrowth and differentiation, suggesting that amphoterin may interact with other molecules to exert its effect in this context. Interestingly, the survival of the neuroblastoma cells treated with retinoic acid was partly dependent on the expression of RAGE, and inhibition of RAGE function partially blocked the increase in anti-apoptotic protein Bcl-2 following retinoic acid treatment. Based on these results we propose that a combination therapy using RAGE blockers and retinoic acid may prove as a useful approach for chemotherapy for the treatment of neuroblastoma.

  1. 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

  2. The pathological role of advanced glycation end products-downregulated heat shock protein 60 in islet β-cell hypertrophy and dysfunction

    PubMed Central

    Wu, Cheng-Tien; Yang, Ting-Hua; Chiang, Chih-Kang; Liu, Shing-Hwa

    2016-01-01

    Heat shock protein 60 (HSP60) is a mitochondrial chaperone. Advanced glycation end products (AGEs) have been shown to interfere with the β-cell function. We hypothesized that AGEs induced β-cell hypertrophy and dysfunction through a HSP60 dysregulation pathway during the stage of islet/β-cell hypertrophy of type-2-diabetes. We investigated the role of HSP60 in AGEs-induced β-cell hypertrophy and dysfunction using the models of diabetic mice and cultured β-cells. Hypertrophy, increased levels of p27Kip1, AGEs, and receptor for AGEs (RAGE), and decreased levels of HSP60, insulin, and ATP content were obviously observed in pancreatic islets of 12-week-old db/db diabetic mice. Low-concentration AGEs significantly induced the cell hypertrophy, increased the p27Kip1 expression, and decreased the HSP60 expression, insulin secretion, and ATP content in cultured β-cells, which could be reversed by RAGE neutralizing antibody. HSP60 overexpression significantly reversed AGEs-induced hypertrophy, dysfunction, and ATP reduction in β-cells. Oxidative stress was also involved in the AGEs-decreased HSP60 expression in β-cells. Pancreatic sections from diabetic patient showed islet hypertrophy, increased AGEs level, and decreased HSP60 level as compared with normal subject. These findings highlight a novel mechanism by which a HSP60-correlated signaling pathway contributes to the AGEs-RAGE axis-induced β-cell hypertrophy and dysfunction under diabetic hyperglycemia. PMID:27056903

  3. 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

  4. 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

  5. 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

  6. Suppression of antioxidant Nrf-2 and downstream pathway in H9c2 cells by advanced glycation end products (AGEs) via ERK phosphorylation.

    PubMed

    Ko, Shun-Yao; Chang, Shu-Shing; Lin, I-Hsuan; Chen, Hong-I

    2015-11-01

    Diabetic cardiomyopathy is related to oxidative stress and correlated with the presence of advanced glycation end products (AGEs). In a clinical setting, AGEs can be detected in patients presenting diabetic cardiomyopathy; however, the underlying mechanism has yet to be elucidated. In our previous study, AGEs increase cell hypertrophy via ERK phosphorylation in a process closely related to ROS production. Thus, we propose that AGEs regulate the antioxidant gene nuclear factor-erythroid 2-related factor (Nrf-2). In H9c2 cells treated with AGEs, the expression of Nrf-2 was reduced; however, ERK phosphorylation was shown to increase. Treatment with H2O2 was also shown to increase Nrf-2 and ERK phosphorylation. In cells pretreatment with ROS scavenger NAC, the effects of H2O2 were reduced; however, the effects of the AGEs remained largely unchanged. Conversely, when cells were pretreated with PD98059 (ERK inhibitor), the expression of Nrf-2 was recovered following treatment with AGEs. Our results suggest that AGEs inhibit Nrf-2 via the ERK pathway; however, this influence is partly associated with ROS. Our finding further indicated that AGEs possess both ROS-dependent and ROS-independent pathways, resulting in a reduction in Nrf-2. This report reveals an important mechanism underlying the regulation of diabetic cardiomyopathy progression by AGEs. PMID:26212730

  7. Effect of PKC-β Signaling Pathway on Expression of MCP-1 and VCAM-1 in Different Cell Models in Response to Advanced Glycation End Products (AGEs)

    PubMed Central

    Rempel, Lisienny C. T.; Finco, Alessandra B.; Maciel, Rayana A. P.; Bosquetti, Bruna; Alvarenga, Larissa M.; Souza, Wesley M.; Pecoits-Filho, Roberto; Stinghen, Andréa E. M.

    2015-01-01

    Advanced glycation end products (AGEs) are compounds classified as uremic toxins in patients with chronic kidney disease that have several pro-inflammatory effects and are implicated in the development of cardiovascular diseases. To explore the mechanisms of AGEs–endothelium interactions through the receptor for AGEs (RAGE) in the PKC-β pathway, we evaluated the production of MCP-1 and VCAM-1 in human endothelial cells (HUVECs), monocytes, and a coculture of both. AGEs were prepared by albumin glycation and characterized by absorbance and electrophoresis. The effect of AGEs on cell viability was assessed with an MTT assay. The cells were also treated with AGEs with and without a PKC-β inhibitor. MCP-1 and VCAM-1 in the cell supernatants were estimated by ELISA, and RAGE was evaluated by immunocytochemistry. AGEs exposure did not affect cell viability, but AGEs induced RAGE, MCP-1, and VCAM-1 expression in HUVECs. When HUVECs or monocytes were incubated with AGEs and a PKC-β inhibitor, MCP-1 and VCAM-1 expression significantly decreased. However, in the coculture, exposure to AGEs and a PKC-β inhibitor produced no significant effect. This study demonstrates, in vitro, the regulatory mechanisms involved in MCP-1 production in three cellular models and VCAM-1 production in HUVECs, and thus mimics the endothelial dysfunction caused by AGEs in early atherosclerosis. Such mechanisms could serve as therapeutic targets to reduce the harmful effects of AGEs in patients with chronic kidney disease. PMID:26008233

  8. 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

  9. The receptor for advanced glycation end-products (RAGE) plays a key role in the formation of nanotubes (NTs) between peritoneal mesothelial cells and in murine kidneys.

    PubMed

    Ranzinger, Julia; Rustom, Amin; Heide, Danijela; Morath, Christian; Schemmer, Peter; Nawroth, Peter P; Zeier, Martin; Schwenger, Vedat

    2014-09-01

    The receptor for advanced glycation end-products (RAGE), a multiligand receptor of the immunoglobulin superfamily, takes part in various inflammatory processes. The role of this receptor in the context of intercellular communication, like nanotube (NT)-mediated interaction, is largely unknown. Here, we use cell cultures of human and murine peritoneal mesothelial cells as well as murine kidneys from wild-type and RAGE knockout mouse models to assess the role of RAGE in NT formation and function. We show that loss of RAGE function results in reduced NT numbers under physiological conditions and demonstrate the involvement of MAP kinase signaling in NT formation. Additionally, we show for the first time the existence of NTs in murine kidney tissue and confirm the correlation of RAGE expression and NT numbers. Under elevated oxidative stress conditions like renal ischemia or peritoneal dialysis, we demonstrate that RAGE absence does not prevent NT formation. Rather, increased NT numbers and attenuated kidney tissue damage could be observed, indicating that, depending on the predominant conditions, RAGE affects NT formation with implications for cellular communication.

  10. Receptor for advanced glycation end products regulates adipocyte hypertrophy and insulin sensitivity in mice: involvement of Toll-like receptor 2.

    PubMed

    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

    2013-02-01

    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.

  11. 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.

  12. 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.

  13. The in vitro protective effects of curcumin and demethoxycurcumin in Curcuma longa extract on advanced glycation end products-induced mesangial cell apoptosis and oxidative stress.

    PubMed

    Liu, Ji-ping; Feng, Liang; Zhu, Mao-mao; Wang, Ru-Shang; Zhang, Ming-hua; Hu, Shao-ying; Jia, Xiao-bin; Wu, Jin-Jie

    2012-11-01

    Curcuma longa L. (CLL), a traditional herbal medicine, has been widely used for the prevention of diabetic vascular complications in recent years. However, the protective effects of curcuminoids in CLL on the AGEs-induced damage to mesangial cell are not fully understood. In this present study, dihydroethidium, superoxide dismutase kit, malondialdehyde kit, and acridine orange/ethidium bromide staining methods were used to evaluate the activities of curcumin and demethoxycurcumin (10(-11)-10(-9) M) on AGEs-induced oxidative stress and apoptosis, which were associated with the damage to mesangial cell. The results showed that these two compounds could significantly restore advanced glycation end products (AGEs)-induced apoptosis to normal levels (IC50 = 3.874 × 10(-11) M for curcumin and IC50 = 6.085 × 10(-11) M for demethoxycurcumin) and reduce remarkably reactive oxygen species generation in mesangial cell. Furthermore, curcumin and demethoxycurcumin dramatically elevated AGEs-decreased superoxide dismutase activity while significantly reducing AGEs-increased malondialdehyde content in cell culture supernatant. Our results suggest that both curcumin and demethoxycurcumin have a significant protective potential to the prevention of diabetic nephropathy.

  14. 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

  15. 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.

  16. Circulating soluble receptor for advanced glycation end products (sRAGE) as a biomarker of emphysema and the RAGE axis in the lung.

    PubMed

    Yonchuk, John G; Silverman, Edwin K; Bowler, Russell P; Agustí, Alvar; Lomas, David A; Miller, Bruce E; Tal-Singer, Ruth; Mayer, Ruth J

    2015-10-01

    Chronic obstructive pulmonary disease (COPD) is a complex and heterogeneous disease that has been traditionally characterized by incompletely reversible airflow limitation. Yet, the latter is poorly correlated with many other clinically relevant characteristics of the disease. Thus, the identification of biomarkers to more accurately assess this heterogeneity and disease severity may facilitate the discovery and development of new treatments and better management of patients with COPD. One molecule that has attracted attention as a potentially useful biomarker specifically for the emphysema subpopulation is the soluble receptor for advanced glycation end products (sRAGE). As the soluble isoform of a key proinflammatory signaling receptor, sRAGE acts as a "decoy" for RAGE ligands and prevents their interaction with the receptor. Multiple reports have now linked sRAGE to COPD, and more specifically to emphysema, and evidence is accumulating that this link is likely mechanistic in nature. Here we review the current state of knowledge about sRAGE biology, the mechanistic links to COPD, and the evidence for using it as a biomarker for emphysema. We also discuss sRAGE as a potential target for therapeutic intervention in COPD.

  17. 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.

  18. 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

  19. Soluble Receptor for Advanced Glycation End Product Ameliorates Chronic Intermittent Hypoxia Induced Renal Injury, Inflammation, and Apoptosis via P38/JNK Signaling Pathways

    PubMed Central

    Wu, Xu; Gu, Wenyu; Lu, Huan; Liu, Chengying; Yu, Biyun; Xu, Hui; Tang, Yaodong

    2016-01-01

    Obstructive sleep apnea (OSA) associated chronic kidney disease is mainly caused by chronic intermittent hypoxia (CIH) triggered tissue damage. Receptor for advanced glycation end product (RAGE) and its ligand high mobility group box 1 (HMGB1) are expressed on renal cells and mediate inflammatory responses in OSA-related diseases. To determine their roles in CIH-induced renal injury, soluble RAGE (sRAGE), the RAGE neutralizing antibody, was intravenously administered in a CIH model. We also evaluated the effect of sRAGE on inflammation and apoptosis. Rats were divided into four groups: (1) normal air (NA), (2) CIH, (3) CIH+sRAGE, and (4) NA+sRAGE. Our results showed that CIH accelerated renal histological injury and upregulated RAGE-HMGB1 levels involving inflammatory (NF-κB, TNF-α, and IL-6), apoptotic (Bcl-2/Bax), and mitogen-activated protein kinases (phosphorylation of P38, ERK, and JNK) signal transduction pathways, which were abolished by sRAGE but p-ERK. Furthermore, sRAGE ameliorated renal dysfunction by attenuating tubular endothelial apoptosis determined by immunofluorescence staining of CD31 and TUNEL. These findings suggested that RAGE-HMGB1 activated chronic inflammatory transduction cascades that contributed to the pathogenesis of the CIH-induced renal injury. Inhibition of RAGE ligand interaction by sRAGE provided a therapeutic potential for CIH-induced renal injury, inflammation, and apoptosis through P38 and JNK pathways. PMID:27688824

  20. Development, relative validity, and reliability of a food frequency questionnaire for a case-control study on dietary advanced glycation end products and diabetes complications.

    PubMed

    Luevano-Contreras, Claudia; Durkin, Taylor; Pauls, Maria; Chapman-Novakofski, Karen

    2013-12-01

    Dietary advanced glycation end products (dAGEs) could be involved on diabetes complications, yet their quantification is not standardized. The objective of this study was to design a food frequency questionnaire (FFQ) for dAGEs, and to assess its reliability and validity. For the design, data from 30 subjects was used. The final instrument had 90 food items. To measure reliability and validity, 20 participants with type 2 diabetes filled out twice the FFQ (FFQ-T1, FFQ-T2) and 7-day food records (7-dFR). The Shrout-Fleiss coefficient was 0.98 showing good reliability. For validation, the results for the weighted kappa were 0.55 (moderate agreement) for FFQ-T1 and 0.64 (good agreement) for FFQ-T2, and 75% and 80% of subjects respectively were correctly classified into tertiles; Bland-Altman graphics showed no systematic bias. This FFQ is comparable to 7-dFR for measuring dAGEs. To our knowledge, this is the first questionnaire designed to measure specifically dAGEs.

  1. Prognostic Potential and Tumor Growth–Inhibiting Effect of Plasma Advanced Glycation End Products in Non–Small Cell Lung Carcinoma

    PubMed Central

    Bartling, Babett; Hofmann, Hans-Stefan; Sohst, Antonia; Hatzky, Yvonne; Somoza, Veronika; Silber, Rolf-Edgar; Simm, Andreas

    2011-01-01

    The plasma fluorescence related to the standard fluorescence of advanced glycation end products (AGEs) is a simple measurable blood parameter for distinct diseases but its importance in human cancer, including non–small cell lung carcinoma (NSCLC), is unknown. Plasma samples of 70 NSCLC patients who underwent resection surgery of the tumor were analyzed for the distinct AGE-related fluorescence at 370 nm excitation/440 nm emission. In a retrospective study, we tested the prognostic relevance of this AGE-related plasma fluorescence. The effect of circulating AGEs on the NSCLC growth was studied experimentally in vitro and in vivo. NSCLC patients with high (> median) AGE-related plasma fluorescence were characterized by a later reoccurrence of the tumor after curative surgery and a higher survival rate compared with patients with low plasma fluorescence (25% versus 47% 5-y survival, P = 0.011). Treating NSCLC cell spheroids with patients’ plasma showed an inverse correlation between the growth of spheroids in vitro and the individual AGE-related fluorescence of each plasma sample. To confirm the impact of circulating AGEs on the NSCLC progression, we studied the NSCLC growth in mice whose circulating AGE level was elevated by AGE-rich diet. In vivo tumorigenicity assays demonstrated that mice with higher levels of circulating AGEs developed smaller tumors than mice with normal AGE levels. The AGE-related plasma fluorescence has prognostic relevance for NSCLC patients in whom the tumor growth-inhibiting effect of circulating AGEs might play a critical role. PMID:21629968

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

    PubMed

    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

    2016-04-01

    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.

  3. Soluble Receptor for Advanced Glycation End Product Ameliorates Chronic Intermittent Hypoxia Induced Renal Injury, Inflammation, and Apoptosis via P38/JNK Signaling Pathways

    PubMed Central

    Wu, Xu; Gu, Wenyu; Lu, Huan; Liu, Chengying; Yu, Biyun; Xu, Hui; Tang, Yaodong

    2016-01-01

    Obstructive sleep apnea (OSA) associated chronic kidney disease is mainly caused by chronic intermittent hypoxia (CIH) triggered tissue damage. Receptor for advanced glycation end product (RAGE) and its ligand high mobility group box 1 (HMGB1) are expressed on renal cells and mediate inflammatory responses in OSA-related diseases. To determine their roles in CIH-induced renal injury, soluble RAGE (sRAGE), the RAGE neutralizing antibody, was intravenously administered in a CIH model. We also evaluated the effect of sRAGE on inflammation and apoptosis. Rats were divided into four groups: (1) normal air (NA), (2) CIH, (3) CIH+sRAGE, and (4) NA+sRAGE. Our results showed that CIH accelerated renal histological injury and upregulated RAGE-HMGB1 levels involving inflammatory (NF-κB, TNF-α, and IL-6), apoptotic (Bcl-2/Bax), and mitogen-activated protein kinases (phosphorylation of P38, ERK, and JNK) signal transduction pathways, which were abolished by sRAGE but p-ERK. Furthermore, sRAGE ameliorated renal dysfunction by attenuating tubular endothelial apoptosis determined by immunofluorescence staining of CD31 and TUNEL. These findings suggested that RAGE-HMGB1 activated chronic inflammatory transduction cascades that contributed to the pathogenesis of the CIH-induced renal injury. Inhibition of RAGE ligand interaction by sRAGE provided a therapeutic potential for CIH-induced renal injury, inflammation, and apoptosis through P38 and JNK pathways.

  4. 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.

  5. 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

  6. Advanced glycation end products impair K(Ca)3.1- and K(Ca)2.3-mediated vasodilatation via oxidative stress in rat mesenteric arteries.

    PubMed

    Zhao, Li-Mei; Wang, Yan; Ma, Xiao-Zhen; Wang, Nan-Ping; Deng, Xiu-Ling

    2014-02-01

    The present study was designed to investigate the role of advanced glycation end products (AGEs) in intermediate-conductance and small-conductance Ca(2+)-activated potassium channels (KCa3.1 and KCa2.3)-mediated relaxation in rat resistance arteries and the underlying mechanism. The endothelial function of mesenteric arteries was assessed with the use of wire myography. Expression levels of KCa3.1 and KCa2.3 were measured by using Western blot. Reactive oxygen species (ROS) were measured by using dihydroethidium and 2', 7'-dichlorofluorescein diacetate. KCa3.1 and KCa2.3-mediated vasodilatation responses to acetylcholine and NS309 (opener of KCa3.1 and KCa2.3) were impaired by incubation of the third-order mesenteric arteries from normal rats with AGEs (200 μg ml(-1) for 3 h). In cultured human umbilical vein endothelial cells (HUVECs), AGEs increased ROS level and decreased the protein expression of KCa3.1 and KCa2.3. Antioxidant alpha lipoic acid restored the impairment in both vasodilatation function and expression of KCa3.1 and KCa2.3. H2O2 could mimic the effect of AGEs on the protein expression of KCa3.1 and KCa2.3 in cultured HUVECs. These results demonstrate for the first time that AGEs impaired KCa3.1 and KCa2.3-mediated vasodilatation in rat mesenteric arteries via downregulation of both KCa3.1 and KCa2.3, in which the enhanced oxidative stress was involved.

  7. 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

  8. 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.

  9. Altered serum glyceraldehyde-derived advanced glycation end product (AGE) and soluble AGE receptor levels indicate carbonyl stress in patients with schizophrenia.

    PubMed

    Takeda, Mayu; Ohnuma, Tohru; Takeuchi, Masayoshi; Katsuta, Narimasa; Maeshima, Hitoshi; Takebayashi, Yuto; Higa, Motoyuki; Nakamura, Toru; Nishimon, Shohei; Sannohe, Takahiro; Hotta, Yuri; Hanzawa, Ryo; Higashiyama, Ryoko; Shibata, Nobuto; Gohda, Tomohito; Suzuki, Yusuke; Yamagishi, Sho-ichi; Tomino, Yasuhiko; Arai, Heii

    2015-04-23

    Recent cross-sectional and longitudinal studies indicate that measurements of peripheral blood carbonyl stress markers such as the advanced glycation end product (AGE) pentosidine and the reactive carbonyl-detoxifying B6 vitamin pyridoxal could be used as therapeutic biological markers in subpopulations of schizophrenia patients. Glyceraldehyde-derived AGEs (Glycer-AGE) have strong neurotoxicity, and soluble receptors for AGEs (sRAGE) may ameliorate the effects of AGEs. In the present study, we measured Glycer-AGEs and sRAGE levels to determine their potential as diagnostic, therapeutic, or clinical biological markers in patients with schizophrenia. After enrollment of 61 admitted Japanese patients with acute schizophrenia and 39 healthy volunteers, 54 patients were followed up from the acute stage to remission. Serum biomarkers were measured in blood samples taken before breakfast using competitive enzyme-linked immunosorbent assays, and Glycer-AGEs were significantly higher and sRAGE levels were significantly lower in patients with acute schizophrenia than in healthy controls. Glycer-AGEs/sRAGE ratios were also higher in schizophrenia patients and were stable during the clinical course. Furthermore, discriminant analyses confirmed that Glycer-AGEs and Glycer-AGEs/sRAGE ratios are significant diagnostic markers for schizophrenia, and distinguished between patients and healthy controls in 70.0% of cases. However, these markers of carbonyl stress were not correlated with clinical features, including disease severity, or with daily chlorpromazine doses. These data indicate the potential of Glycer-AGEs, RAGEs, and their relative ratios as diagnostic markers for patients with schizophrenia.

  10. 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

  11. Co-localisation of advanced glycation end products and d-β-aspartic acid-containing proteins in gelatinous drop-like corneal dystrophy

    PubMed Central

    Oshika, Tetsuro; Takazawa, Yutaka; Fukayama, Masashi; Fujii, Noriko

    2012-01-01

    Purpose Gelatinous drop-like corneal dystrophy (GDLD), also known as familial subepithelial corneal amyloidosis, is an autosomal recessive disorder that causes progressive corneal opacity due to accumulation of amyloid fibrils in the corneal stroma. Genetic analyses have revealed that a mutation in membrane component chromosome 1 surface marker 1 gene is responsible for GDLD. However, the mechanism of amyloid formation in the corneal stroma remains unclear. The present study attempted to reveal the role of advanced glycation end products (AGE) and d-amino acids in amyloid formation in GDLD. Methods Informed consent was obtained from five patients with GDLD, three patients with bullous keratopathy and three patients with interstitial keratitis and all the specimens were analysed. Localisation of amyloid fibrils was analysed using Congo-red and thioflavin T staining. In addition, the localisation of AGE (Nɛ-carboxy(methyl)-l-lysine, pyrraline and pentosidine) and d-β-aspartic acid-containing proteins, a major form of d-amino acid-containing proteins, was analysed immunohistochemically. Results In all GDLD specimens, strong immunoreactivity to AGE and d-β-aspartic acid-containing proteins was detected in the subepithelial amyloid-rich region. In contrast, amyloid fibrils, AGE, or d-amino acid-containing proteins were slightly detected in the corneal stroma of patients with bullous keratopathy and interstitial keratitis. Conclusions Abnormally accumulated proteins rich in AGE and d-β-aspartic acid co-localise in the amyloid lesions in GDLD. These results indicate that non-enzymatic post-translational modifications of proteins, including AGE formation and isomerisation of aspartyl residues, will be the cause as well as the result of amyloid fibril formations in GDLD. PMID:22694960

  12. Dietary advanced glycation end-product restriction for the attenuation of insulin resistance, oxidative stress and endothelial dysfunction: a systematic review.

    PubMed

    Kellow, N J; Savige, G S

    2013-03-01

    The benefits of advanced glycation end-product (AGE)-restricted diets in humans are unclear. This review aimed to determine the effect of dietary AGE restriction on the inflammatory profiles of healthy adults and adults with diabetes or renal failure. Eight computer databases were searched for controlled feeding trials published in English between January 1997 and December 2012. Human trials were included if at least one group received an AGE-restricted dietary intervention. A total of 12 trials reporting on 289 participants were included in the review. Five trials (42%) were of high methodological quality. Meta-analysis of two long-term (16 week) trials provided evidence favoring an AGE-restricted diet for the reduction of 8-isoprostanes (standardized mean difference 0.9; 95% confidence interval (CI): 0.3-1.5) and tumor necrosis factor-α (1.3; 95% CI: 0.6-1.9) in healthy adults. Intermediate-term dietary AGE restriction in adults with chronic renal failure reduced serum VCAM-1 (0.9; 95% CI: 0.1-1.7). Individual trials provided some evidence that long-term dietary AGE restriction reduces HOMA-IR (1.4; 95% CI: 0.3-2.6) and AGE-modified low-density lipoprotein (2.7; 95% CI: 1.6-3.9) in adults with type 2 diabetes. Generalisability is limited, as 75% of studies were of less than 6 weeks duration and more than half were of low methodological quality. Evidence quality ranged from low to very low, limiting the conclusions that can be drawn from this review. There is currently insufficient evidence to recommend dietary AGE restriction for the alleviation of the proinflammatory milieu in healthy individuals and patients with diabetes or renal failure. Additional long-term high-quality RCTs with larger sample sizes measuring patient-important outcomes are required to strengthen the evidence supporting the effects of AGE-restricted diets.

  13. Endocytic uptake of advanced glycation end products by mouse liver sinusoidal endothelial cells is mediated by a scavenger receptor distinct from the macrophage scavenger receptor class A.

    PubMed Central

    Matsumoto, K; Sano, H; Nagai, R; Suzuki, H; Kodama, T; Yoshida, M; Ueda, S; Smedsrød, B; Horiuchi, S

    2000-01-01

    Previous studies with peritoneal macrophages obtained from macrophage scavenger receptor class A (MSR-A) knock-out mice showed that the endocytic uptake of advanced glycation end products (AGE) by macrophages was mediated mainly by MSR-A. However, it is controversial whether the endocytic uptake of intravenously injected AGE proteins by liver sinusoidal endothelial cells (LECs) is similarly explained by receptor-mediated endocytosis via MSR-A. The present study was conducted to compare the capacity to endocytose AGE proteins in LECs and peritoneal macrophages obtained from MSR-A knock-out and littermate wild-type mice. The endocytic degradation capacity of MSR-A knock-out LECs for AGE-BSA was indistinguishable from that of wild-type LECs, whereas that of MSR-A knock-out peritoneal macrophages for AGE-BSA was decreased to 30% of that in wild-type cells. Similarly, the endocytic degradation of MSR-A knock-out LECs for acetylated low-density lipoprotein (acetyl-LDL) did not differ from that of wild-type LECs, whereas the endocytic degradation of acetyl-LDL by MSR-A knock-out peritoneal macrophages was less than 20% of that in wild-type cells. Furthermore, formaldehyde-treated serum albumin (f-Alb), a ligand known to undergo scavenger-receptor-mediated endocytosis by LECs, was effectively taken up by MSR-A knock-out LECs at a capacity that did not differ from that of wild-type LECs. Moreover, the endocytic uptake of AGE-BSA by LECs was effectively competed for by unlabelled f-Alb or acetyl-LDL. These results indicate that the scavenger-receptor ligands AGE proteins, acetyl-LDL and f-Alb are endocytosed by LECs through a non-MSR-A pathway. PMID:11062078

  14. 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.

  15. Kinetics, role and therapeutic implications of endogenous soluble form of receptor for advanced glycation end products (sRAGE) in diabetes.

    PubMed

    Yamagishi, Sho-ichi; Matsui, Takanori; Nakamura, Kazuo

    2007-10-01

    Reducing sugars can react non-enzymatically with amino groups of protein to form Amadori products. These early glycation products undergo further complex reaction such as rearrangement, dehydration, and condensation to become irreversibly cross-linked, heterogeneous fluorescent derivatives, termed advanced glycation end products (AGEs). The formation and accumulation of AGEs have been known to progress at an accelerated rate in diabetes. There is a growing body of evidence that AGEs and their receptor (RAGE) axis is implicated in the pathogenesis of diabetic vascular complications. Indeed, the engagement of RAGE with AGEs is shown to elicit oxidative stress generation and subsequently evoke inflammatory responses in various types of cells, thus playing an important role in the development and progression of diabetic micro- and macroangiopathy. Moreover, administration of a recombinant soluble form of RAGE (sRAGE), has been shown to suppress the development of accelerated atherosclerosis in diabetic apolipoprotein E-null mice. These observations suggest that exogenously administered sRAGE may capture and eliminate circulating AGEs, thus protecting against the AGEs-elicited tissue damage by acting as a decoy receptor. Recently, endogenous sRAGE has been identified in humans. However, there is few comprehensive review about the regulation and role of endogenous sRAGE in diabetes. In the former part of this paper, we review the role of the AGE-RAGE system in the pathogenesis of diabetic vascular complications. Then we summarize in the latter part of this review the kinetics and pathophysiological role of endogenous sRAGE in diabetes. We also discuss the possibility that endogenous sRAGE may be a therapeutic target for the prevention of diabetic vascular complications. PMID:17979674

  16. Serum soluble receptor for advanced glycation end products (sRAGE) is independently associated with cigarette smoking in non-diabetic healthy subjects.

    PubMed

    Biswas, Subrata K; Mudi, Sonchita R; Mollah, Forhadul H; Bierhaus, Angelika; Arslan, M Iqbal

    2013-07-01

    This study was designed to explore the relationship between serum levels of soluble receptor for advanced glycation end products (sRAGE) and cigarette smoking in non-diabetic healthy subjects. A total of 98 non-diabetic, otherwise healthy male subjects were recruited. A fasting blood sample and medical history including detail history of cigarette smoking was collected. The serum sRAGE levels were found significantly higher (p=0.002) in cigarette smokers (1475±422 pg/ml, n=45) compared with non-smokers (1165±350 pg/ml, n=53). Moreover, among the cigarette smokers, serum sRAGE levels were found significantly correlated with number of cigarettes smoked per day (r=0.60, p<0.001). In bivariate analysis in the total population, sRAGE positively correlated with smoking habit (r=0.37, p=0.002) and negatively correlated with systolic (r=-0.32, p=0.01) and diastolic blood pressure (r=-0.36, p=0.003). However, in stepwise multivariate linear regression model, sRAGE showed a significant independent association with smoking habit (b=0.32, p=0.007, R2=0.23). In conclusion, this study for the first time shows a significant elevation of serum sRAGE in cigarette smokers compared with non-smokers, a strong correlation between sRAGE and number of cigarettes smoked per day and an independent association of sRAGE with smoking habit in non-diabetic healthy subjects.

  17. 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

  18. 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

  19. 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

  20. High-mobility group box 1 inhibits gastric ulcer healing through Toll-like receptor 4 and receptor for advanced glycation end products.

    PubMed

    Nadatani, Yuji; Watanabe, Toshio; Tanigawa, Tetsuya; Ohkawa, Fumikazu; Takeda, Shogo; Higashimori, Akira; Sogawa, Mitsue; Yamagami, Hirokazu; Shiba, Masatsugu; Watanabe, Kenji; Tominaga, Kazunari; Fujiwara, Yasuhiro; Takeuchi, Koji; Arakawa, Tetsuo

    2013-01-01

    High-mobility group box 1 (HMGB1) was initially discovered as a nuclear protein that interacts with DNA as a chromatin-associated non-histone protein to stabilize nucleosomes and to regulate the transcription of many genes in the nucleus. Once leaked or actively secreted into the extracellular environment, HMGB1 activates inflammatory pathways by stimulating multiple receptors, including Toll-like receptor (TLR) 2, TLR4, and receptor for advanced glycation end products (RAGE), leading to tissue injury. Although HMGB1's ability to induce inflammation has been well documented, no studies have examined the role of HMGB1 in wound healing in the gastrointestinal field. The aim of this study was to evaluate the role of HMGB1 and its receptors in the healing of gastric ulcers. We also investigated which receptor among TLR2, TLR4, or RAGE mediates HMGB1's effects on ulcer healing. Gastric ulcers were induced by serosal application of acetic acid in mice, and gastric tissues were processed for further evaluation. The induction of ulcer increased the immunohistochemical staining of cytoplasmic HMGB1 and elevated serum HMGB1 levels. Ulcer size, myeloperoxidase (MPO) activity, and the expression of tumor necrosis factor α (TNFα) mRNA peaked on day 4. Intraperitoneal administration of HMGB1 delayed ulcer healing and elevated MPO activity and TNFα expression. In contrast, administration of anti-HMGB1 antibody promoted ulcer healing and reduced MPO activity and TNFα expression. TLR4 and RAGE deficiency enhanced ulcer healing and reduced the level of TNFα, whereas ulcer healing in TLR2 knockout (KO) mice was similar to that in wild-type mice. In TLR4 KO and RAGE KO mice, exogenous HMGB1 did not affect ulcer healing and TNFα expression. Thus, we showed that HMGB1 is a complicating factor in the gastric ulcer healing process, which acts through TLR4 and RAGE to induce excessive inflammatory responses.

  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. Amyloid-beta mediates the receptor of advanced glycation end product-induced pro-inflammatory response via toll-like receptor 4 signaling pathway in retinal ganglion cell line RGC-5.

    PubMed

    Lee, Jong-Jer; Wang, Pei-Wen; Yang, I-Hui; Wu, Chia-Lin; Chuang, Jiin-Haur

    2015-07-01

    Patients with diabetes mellitus have an increased risk of developing Alzheimer's disease. Amyloid-β, a product of amyloid precursor protein, is associated with neuro-inflammation in patients with Alzheimer's diseases. The correlation between amyloid-beta and advanced glycation end products, which accumulate in tissue of diabetic patients, is not clear. The aims of this study were to determine the effect of advanced glycation end product on the expression of amyloid precursor protein/amyloid-beta and associated pro-inflammatory responses in retinal ganglion cell line RGC-5. Treatment with advanced glycation end product produced upregulation of amyloid precursor protein and increased secretion of amyloid-β(1-40). Additionally, amyloid-β(1-40) induced toll-like receptor 4-dependent phosphorylation of tyrosine in myeloid differentiation primary response gene (88). We found that N-[N-(3,5-Difluorophenacetyl)-l-alanyl]-S-phenylglycine t-butyl ester, a γ-secretase inhibitor, reduced the secretion of amyloid-β(1-40) and inhibited the advanced glycation end product-induced activation of myeloid differentiation primary response gene (88). Amyloid-β(1-40) induced the activation of NF-κB and the expression of TNFα mRNA. Knockdown of toll-like receptor 4 inhibited the amyloid-β(1-40)-induced phosphorylation of p65 in NF-κB. Additionally, the nuclear translocation of p65 and transcriptions of TNFα were inhibited by siRNA knockdown of receptor of advanced glycation end product or toll-like receptor 4. The advanced glycation end product-induced secretion of VEGF-A was also reduced by knockdown of toll-like receptor 4. Taken together, our data suggested that amyloid-β(1-40) mediates the interaction between receptor of advanced glycation end product and toll-like receptor 4. Inhibition of the toll-like receptor 4 is an effective method for suppressing the amyloid-β(1-40)-induced pro-inflammatory responses in RGC-5 cells.

  3. The effects of Advanced Glycation End Products (RAGE)-374T/A and Gly82Ser variants and soluble-RAGE levels to obesity in children.

    PubMed

    Kucukhuseyin, O; Ozgen, T; Karagedik, E H; Cesur, Y; Yilmaz Aydogan, H; Yaylim, I; Ergen, H A

    2016-04-30

    In recent years, studies related to advanced glycation end products (AGE) and their interaction with their receptors (RAGE) have advanced our knowledge of the roles of these molecules in different diseases. However, studies concerning AGE-RAGE interaction in obesity are limited and the results are conflicting. RAGE gene is located on 6p21.3, has several polymorphic sites including -374T/A, a functional polymorphism in the promoter region, and Gly82Ser, present within the ligand-binding domain. In the present study, the determination of possible risks in the development of obesity according to RAGE polymorhisms and plasma levels of RAGE (sRAGE) was aimed. 87 obese and 78 healthy children were included in this study. Genomic DNA was isolated with salting-out procedure. RAGE polymorphisms were analyzed by PCR based techniques. In contrast to Gly82Ser, -374T/A allelic and genotypic frequencies were not different between study groups. Ser(SerSer+GlySer genotype) allele frequency was higher in obese cases than controls (74.20%→25.80%,OR:2.573,95%CI:1.789-3.699;p<0.01). In obese cases, blood glycose (92.50±2.80→87.00±1.16; p=0.025) and HDL-C (46.14±2.75→39.84±1.82;p=0.057) levels were higher than TT genotype carriers. As for Gly82Ser polymorphism, HDL-C (p=0.004) and FT4 (p=0.020) levels were different in obese cases, the order was SerSer>GlySer>GlyGly for HDL-C, and opposite for FT4. Besides, Ser carriers had lower insulin (p=0.038) and homa-IR (p=0.081) levels than GG genotype. sRAGE levels were different between obese and control seperately or in combination with RAGE polymorphisms (p<0.05), the order of sRAGE was TT>TA>AA for -374T/A and SerSer>GlyGly>GlySer for Gly82Ser. According to our results SerSer genotype could have significant effects on sRAGE levels, and increased sRAGE levels and Gly82Ser polymorphism either combinatorially or seperately increased the propensity towards obesity.

  4. 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

  5. Immunological evidence that non-carboxymethyllysine advanced glycation end-products are produced from short chain sugars and dicarbonyl compounds in vivo.

    PubMed Central

    Takeuchi, M.; Makita, Z.; Bucala, R.; Suzuki, T.; Koike, T.; Kameda, Y.

    2000-01-01

    BACKGROUND: The Maillard reaction that leads to the formation of advanced glycation end-products (AGE) plays an important role in the pathogenesis of angiopathy in diabetic patients and in the aging process. Recently, it was proposed that AGE were not only created by glucose, but also by dicarbonyl compounds derived from the Maillard reaction, autoxidation of sugars and other metabolic pathways of glucose. In this study, we developed four types of non-carboxymethyllysine (CML) anti-AGE antibodies that recognized proteins modified by incubation with short chain sugars and dicarbonyl compounds. MATERIALS AND METHODS: AGE-modified serum albumins were prepared by incubation of rabbit serum albumin with glyceraldehyde, glycolaldehyde, methylglyoxal or glyoxal. After immunization of rabbits, four types of AGE-specific antisera were obtained that were specific for the AGE modification. To separate non-CML AGE antibodies (Ab) (non-CML AGE-Ab-2, -3, -4, and -5), these anti-AGE antisera were subjected to affinity chromatography on a matrix coupled with four kinds of AGE bovine serum albumin (BSA) or CML-BSA. These non-CML AGE antibodies were used to investigate the AGE content of serum obtained from diabetic patients on hemodialysis. RESULTS: Characterization of the four types of non-CML AGE antibodies obtained by immunoaffinity chromatography was performed by competitive ELISA and immunoblot analysis. Non-CML AGE-Ab-2 crossreacted with the protein modified by glyceraldehyde or glycolaldehyde. Non-CML AGE-Ab-3 and -Ab-4 specifically cross-reacted with protein modified by glycolaldehyde and methylglyoxal, respectively. NonCML AGE-Ab-5 cross-reacted with protein modified with glyoxal as well as methylglyoxal and glycolaldehyde. Three kinds of non-CML AGE (AGE-2, -4, and -5) were detected in diabetic serum as three peaks with apparent molecular weights of 200, 1.15, and 0.85 kD; whereas, AGE-3 was detected as two peaks with apparent molecular weights of 200 and 0.85 k

  6. 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.

  7. 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

  8. 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

  9. 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

  10. 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

  11. 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

  12. Effects of Sevelamer Carbonate on Advanced Glycation End Products and Antioxidant/Pro-Oxidant Status in Patients with Diabetic Kidney Disease

    PubMed Central

    Yubero-Serrano, Elena M.; Woodward, Mark; Poretsky, Leonid; Vlassara, Helen

    2015-01-01

    Background and objectives The primary goals were to re-examine whether sevelamer carbonate (SC) reduces advanced glycation end products (AGEs) (methylglyoxal and carboxymethyllysine [CML]), increases antioxidant defenses, reduces pro-oxidants, and improves hemoglobin A1c (HbA1c) in patients with type 2 diabetes mellitus (T2DM) and diabetic kidney disease (DKD). Secondary goals examined albuminuria, age, race, sex, and metformin prescription. Design, setting, participants, & measurements This two-center, randomized, intention-to-treat, open-label study evaluated 117 patients with T2DM (HbA1c >6.5%) and stages 2–4 DKD (urinary albumin/creatinine ratio ≥200 mg/g) treated with SC (1600 mg) or calcium carbonate (1200 mg), three times a day, without changing medications or diet. Statistical analyses used linear mixed models adjusted for randomization levels. Preselected subgroup analyses of sex, race, age, and metformin were conducted. Results SC lowered serum methylglyoxal (95% confidence interval [CI], −0.72 to −0.29; P<0.001), serum CML (95% CI, −5.08 to −1.35; P≤0.001), and intracellular CML (95% CI, −1.63 to −0.28; P=0.01). SC increased anti-inflammatory defenses, including nuclear factor like-2 (95% CI, 0.58 to 1.29; P=0.001), AGE receptor 1 (95% CI, 0.23 to 0.96; P=0.001), NAD-dependent deacetylase sirtuin-1 (95% CI, 0.20 to 0.86; P=0.002), and estrogen receptor α (95% CI, 1.38 to 2.73; P ≤0.001). SC also decreased proinflammatory factors such as TNF receptor 1 (95% CI, −1.56 to −0.72; P≤0.001) and the receptor for AGEs (95% CI, −0.58 to 1.53; P≤0.001). There were no differences in HbA1c, GFR, or albuminuria in the overall group. Subanalyses showed that SC lowered HbA1c in women (95% CI, −1.71 to −0.27; P=0.01, interaction P=0.002), and reduced albuminuria in those aged <65 years (95% CI, −1.15 to −0.07; P=0.03, interaction P=0.02) and non-Caucasians (95% CI, −1.11 to −0.22; P=0.003, interaction P≤0.001), whereas

  13. 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.

  14. 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

  15. 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

  16. Voltammetric detection of S100B protein using His-tagged receptor domains for advanced glycation end products (RAGE) immobilized onto a gold electrode surface.

    PubMed

    Mikuła, Edyta; Wysłouch-Cieszyńska, Aleksandra; Zhukova, Liliya; Puchalska, Monika; Verwilst, Peter; Dehaen, Wim; Radecki, Jerzy; Radecka, Hanna

    2014-06-17

    In this work we report on an electrochemical biosensor for the determination of the S100B protein. The His-tagged VC1 domains of Receptors for Advanced Glycation End (RAGE) products used as analytically active molecules were covalently immobilized on a monolayer of a thiol derivative of pentetic acid (DPTA) complex with Cu(II) deposited on a gold electrode surface. The recognition processes between the RAGE VC1 domain and the S100B protein results in changes in the redox activity of the DPTA-Cu(II) centres which were measured by Osteryoung square-wave voltammetry (OSWV). In order to verify whether the observed analytical signal originates from the recognition process between the His6-RAGE VC1 domains and the S100B protein, the electrode modified with the His6-RAGE C2 and His6-RAGE VC1 deleted domains which have no ability to bind S100B peptides were applied. The proposed biosensor was quite sensitive, with a detection limit of 0.52 pM recorded in the buffer solution. The presence of diluted human plasma and 10 nM Aβ(1-40) have no influence on the biosensor performance.

  17. Voltammetric Detection of S100B Protein Using His-Tagged Receptor Domains for Advanced Glycation End Products (RAGE) Immobilized onto a Gold Electrode Surface

    PubMed Central

    Mikuła, Edyta; Wysłouch-Cieszyńska, Aleksandra; Zhukova, Liliya; Puchalska, Monika; Verwilst, Peter; Dehaen, Wim; Radecki, Jerzy; Radecka, Hanna

    2014-01-01

    In this work we report on an electrochemical biosensor for the determination of the S100B protein. The His-tagged VC1 domains of Receptors for Advanced Glycation End (RAGE) products used as analytically active molecules were covalently immobilized on a monolayer of a thiol derivative of pentetic acid (DPTA) complex with Cu(II) deposited on a gold electrode surface. The recognition processes between the RAGE VC1 domain and the S100B protein results in changes in the redox activity of the DPTA-Cu(II) centres which were measured by Osteryoung square-wave voltammetry (OSWV). In order to verify whether the observed analytical signal originates from the recognition process between the His6–RAGE VC1 domains and the S100B protein, the electrode modified with the His6–RAGE C2 and His6–RAGE VC1 deleted domains which have no ability to bind S100B peptides were applied. The proposed biosensor was quite sensitive, with a detection limit of 0.52 pM recorded in the buffer solution. The presence of diluted human plasma and 10 nM Aβ1-40 have no influence on the biosensor performance. PMID:24940866

  18. Expression of receptors of advanced glycation end product (RAGE) and types I, III and IV collagen in the vastus lateralis muscle of men in early stages of knee osteoarthritis.

    PubMed

    Serrão, Paula Regina M S; Vasilceac, Fernando A; Gramani-Say, Karina; Lessi, Giovanna C; Reiff, Rodrigo B M; Mattiello-Sverzut, Ana Cláudia; Mattiello, Stela M

    2014-01-01

    Alterations in the contractile and non-contractile proteins of the skeletal muscle may reduce muscle function in knee osteoarthritis (OA), and the formation and accumulation of advanced glycation end products, particularly in collagen, can influence the quality of these muscle proteins. The objective of this study was to evaluate the reactivity of types I, III and IV collagen and the expression and localization of receptor for advanced glycation end products (RAGE) in the vastus lateralis (VL) muscle in early stages of knee OA. The hypothesis was that these patients present a higher expression of RAGE and increased immunoreactivity in the collagen. Thirty-five men were divided into two groups: the control group (CG; n = 17) and the osteoarthritis group (OAG; n = 18). All participants were submitted to a biopsy of the VL. The muscle samples were analyzed by immunohistochemistry for collagen and for RAGE and laminin. The expression of RAGE was counted (intracellular, extracellular and total). Student's t-test for independent samples and Mann-Whitney U test were used for the RAGE's intergroup analysis (α ≤ 0.05). A semiquantitative analysis was performed to assess the collagen reactivity. No significant differences were observed in the intracellular, extracellular or total localization of RAGE (p > 0.05). Higher immunoreactivity was observed in the OAG for all types of collagen, with more reactivity for collagen III and IV. We concluded that in the initial stages of knee OA, no differences were observed for RAGE levels between the groups. However, the OAG's higher collagen expression may represent adaptations for reducing muscle stiffness and avoiding injury.

  19. 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

    You, Jia; Wang, Zai; Xu, Shiqing; Zhang, Wenjian; Fang, Qing; Liu, Honglin; Peng, Liang; Deng, Tingting; Lou, Jinning

    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. PMID:27635403

  20. Metformin Restores Intermediate-Conductance Calcium-Activated K⁺ Channel- and Small-Conductance Calcium-Activated K⁺ Channel-Mediated Vasodilatation Impaired by Advanced Glycation End Products in Rat Mesenteric Artery. [Corrected].

    PubMed

    Zhao, Li-Mei; Wang, Yan; Yang, Yong; Guo, Rong; Wang, Nan-Ping; Deng, Xiu-Ling

    2014-11-01

    The present study was designed to investigate the effect of metformin on the impairment of intermediate-conductance and small-conductance Ca(2+)-activated potassium channels (IKCa and SKCa)-mediated relaxation in diabetes and the underlying mechanism. The endothelial vasodilatation function of mesenteric arteries was assessed with the use of wire myography. Expression levels of IKCa and SKCa and phosphorylated Thr(172) of AMP-activated protein kinase (AMPK) were measured using Western blot technology. The channel activity was observed using a whole-cell patch voltage clamp. Reactive oxygen species (ROS) were measured using dihydroethidium and 2',7'-dichlorofluorescein diacetate. Metformin restored the impairment of IKCa- and SKCa-mediated vasodilatation in mesenteric arteries from streptozotocin-induced type 2 diabetic rats and that from normal rats incubated with advanced glycation end products (AGEs) for 3 hours. In cultured human umbilical vein endothelial cells (HUVECs), 1 μM metformin reversed AGE-induced increase of ROS and attenuated AGE- and H2O2- induced downregulation of IKCa and SKCa after long-term incubation (>24 hours). Short-term treatment (3 hours) with 1 μM metformin reversed the decrease of IKCa and SKCa currents induced by AGE incubation for 3 hours without changing the channel expression or the AMPK activation in HUVECs. These results are the first to demonstrate that metformin restored IKCa- and SKCa-mediated vasodilatation impaired by AGEs in rat mesenteric artery, in which the upregulation of channel activity and protein expression is likely involved.

  1. 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.

  2. 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.

  3. Effect of 2-dodecyl-6-methoxycyclohexa-2,5-diene-1,4-dione, isolated from Averrhoa carambola L. (Oxalidaceae) roots, on advanced glycation end-product-mediated renal injury in type 2 diabetic KKAy mice.

    PubMed

    Zheng, Ni; Lin, Xing; Wen, Qingwei; Kintoko; Zhang, Shijun; Huang, Jianchun; Xu, Xiaohui; Huang, Renbin

    2013-05-10

    The roots of Averrhoa carambola L. (Oxalidaceae) have a long history of medical use in traditional Chinese medicine for treating diabetes and diabetic nephropathy. 2-Dodecyl-6-methoxycyclohexa-2,5-diene-1,4-dione (DMDD) was isolated from the tuberous roots of A. carambola L. The purpose of this study was to investigate the beneficial effect of DMDD on the advanced glycation end-product-mediated renal injury in type 2 diabetic KKAy mice with regard to prove its efficacy by local traditional practitioners in the treatment of kidney frailties in diabetics. KKAy mice were orally administrated DMDD (12.5, 25, 50mg/kg body weight/d) or aminoguanidine (200mg/kg body weight/d) for 8 weeks. Hyperglycemia, renal AGE formation, and the expression of related proteins, such as the AGE receptor, nuclear factor-κB, transforming growth factor-β1, and N(ε)-(carboxymethyl)lysine, were markedly decreased by DMDD. Diabetes-dependent alterations in proteinuria, serum creatinine, creatinine clearance, and serum urea-N and glomerular mesangial matrix expansion were attenuated after treatment with DMDD for 8 weeks. The activities of superoxide dismutase and glutathione peroxidase, which are reduced in the kidneys of KKAy mice, were enhanced by DMDD. These findings suggest that DMDD may inhibit the progression of diabetic nephropathy and may be a therapeutic agent for regulating several pharmacological targets to treat or prevent of diabetic nephropathy.

  4. Peroxisome proliferator-activated receptor δ downregulates the expression of the receptor for advanced glycation end products and pro-inflammatory cytokines in the kidney of streptozotocin-induced diabetic mice.

    PubMed

    Liang, Yao-Jen; Chen, Siang-An; Jian, Jhih-Hao

    2011-05-18

    Activation of peroxisome proliferator-activated receptor δ (PPARδ) plays board beneficial effects in treating metabolic syndrome. The aim of this study is to examine whether PPARδ alters the expression of the receptor for advanced glycation end products (RAGE) and downstream pro-inflammatory cytokines in diabetic nephropathy. Streptozotocin-induced diabetic mice (STZ mice) were injected with a PPARδ agonist, L-165041 (5 μM/kg, intraperitoneal) once daily for 10 days and high glucose-treated cultured HEK cells were also used. After L-165041 treatment, serum TNFα, IL-6 and IL-1 levels were significantly decreased in STZ mice. RAGE mRNA and protein expression were both decreased by L-165041 in kidney tissues of STZ mice. The high glucose incubation increased NF-κB, RAGE and IL-6 expressions in HEK293 cells. These effects were inhibited by L-165041 and specific RAGE siRNA transfection. This study demonstrated that PPARδ may play a beneficial role in preventing diabetic nephropathy. Its downstream signaling may include RAGE and NF-κB pathway. Target on PPARδ will provide new meaningful therapies to patients with diabetic nephropathy.

  5. Plantamajoside Inhibits UVB and Advanced Glycation End Products-Induced MMP-1 Expression by Suppressing the MAPK and NF-κB Pathways in HaCaT Cells.

    PubMed

    Han, Ah-Ram; Nam, Mi-Hyun; Lee, Kwang-Won

    2016-09-01

    Photoaging and glycation stress are major causes of skin deterioration. Oxidative stress caused by ultraviolet B (UVB) irradiation can upregulate matrix metalloprotease 1 (MMP-1), a major enzyme responsible for collagen damage in the skin. Advanced glycation end products (AGEs) accumulate via gradual formation from skin proteins, especially from long-lived proteins such as dermal elastin and collagen. Plantamajoside (PM), isolated from Plantago asiatica, has various biological effects including anti-inflammatory and antioxidant effects. In this study, we assessed the protective effects of PM on a human keratinocyte cell line (HaCaT) and primary human dermal fibroblasts (HDF) against stress caused by glyceraldehyde-induced AGEs (glycer-AGEs) with UVB irradiation. We found that PM attenuated UVB- and-glycer-AGEs-induced MMP-1 expression in HaCaT and HDF cells and proinflammatory cytokines expression by inhibiting the phosphorylation of mitogen-activated protein kinases (MAPKs) activated by reactive oxygen species. Specific inhibitors of NF-κB and MAPKs attenuated the induced expression of MMP-1. PM also inhibited the phosphorylation of IκBα, and reduced nuclear translocation of NF-κB in these cells. Furthermore, PM attenuated the upregulation of receptor for AGEs (RAGE) by glycer-AGEs with UVB irradiation. Therefore, our findings strongly suggest that PM is a promising inhibitor of skin photoaging. PMID:27346084

  6. 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

  7. 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.

  8. 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. PMID:27635403

  9. Receptors for advanced glycosylation endproducts in human brain: role in brain homeostasis.

    PubMed Central

    Li, J. J.; Dickson, D.; Hof, P. R.; Vlassara, H.

    1998-01-01

    BACKGROUND: Advanced glycation end products (AGEs) are the reactive derivatives of nonenzymatic glucose-macromolecule condensation products. Aging human tissues accumulate AGEs in an age-dependent manner and contribute to age-related functional changes in vital organs. We have shown previously that AGE scavenger receptors are present on monocyte/macrophages, lymphocytes, and other cells. However, it remains unclear whether the human brain can efficiently eliminate AGE-modified proteins and whether excessive AGEs can contribute to inflammatory changes leading to brain injury in aging. MATERIALS AND METHODS: To explore the expression and characteristics of AGE-binding proteins on CNS glia components and their putative function, such as degradation of AGE-modified proteins, primary human astrocytes and human monocytes (as a microglial cell surrogate) and murine microglia (N9) cells and cell membrane extracts were used. Immunohistochemistry was used to examine the distribution of AGE-binding proteins in the human hippocampus; RT-PCR techniques were used to examine the biologic effects of AGEs and a model AGE compound, FFI, on AGE-binding protein modulation and cytokine responses of human astrocytes and monocytes. RESULTS: Our results showed that AGE-binding proteins AGE-R1, -R2, and -R3 are present in glial cells. Western blot analyses and radiolabeled ligand binding studies show that AGE-R1 and -R3 from human astrocytes bind AGE-modified proteins; binding could be blocked by anti-AGE-R1 and anti-AGE-R3 antibodies, respectively. Immunohistochemistry showed that AGE-R1 and -R2 are expressed mainly in neurons; only some glial cells express these AGE-binding proteins. In contrast, AGE-R3 was found only on those astrocytes whose positively stained foot processes extend and surround the sheath of microcapillaries. RT-PCR results showed that mRNAs of the three AGE-binding proteins are expressed constitutively in human astrocytes and monocytes, and receptor transcripts are

  10. Advanced analyses of kinetic stabilities of iggs modified by mutations and glycosylation

    PubMed Central

    Sedlák, Erik; Schaefer, Jonas V; Marek, Jozef; Gimeson, Peter; Plückthun, Andreas

    2015-01-01

    The stability of Immunoglobulin G (IgG) affects production, storage and usability, especially in the clinic. The complex thermal and isothermal transitions of IgGs, especially their irreversibilities, pose a challenge to the proper determination of parameters describing their thermodynamic and kinetic stability. Here, we present a reliable mathematical model to study the irreversible thermal denaturations of antibody variants. The model was applied to two unrelated IgGs and their variants with stabilizing mutations as well as corresponding non-glycosylated forms of IgGs and Fab fragments. Thermal denaturations of IgGs were analyzed with three transitions, one reversible transition corresponding to CH2 domain unfolding followed by two consecutive irreversible transitions corresponding to Fab and CH3 domains, respectively. The parameters obtained allowed us to examine the effects of these mutations on the stabilities of individual domains within the full-length IgG. We found that the kinetic stability of the individual Fab fragment is significantly lowered within the IgG context, possibly because of intramolecular aggregation upon heating, while the stabilizing mutations have an especially beneficial effect. Thermal denaturations of non-glycosylated variants of IgG consist of more than three transitions and could not be analyzed by our model. However, isothermal denaturations demonstrated that the lack of glycosylation affects the stability of all and not just of the CH2 domain, suggesting that the partially unfolded domains may interact with each other during unfolding. Investigating thermal denaturation of IgGs according to our model provides a valuable tool for detecting subtle changes in thermodynamic and/or kinetic stabilities of individual domains. PMID:25966898

  11. 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.

  12. Advanced glycation end products (AGEs) on the surface of diabetic erythrocytes bind to the vessel wall via a specific receptor inducing oxidant stress in the vasculature: a link between surface-associated AGEs and diabetic complications.

    PubMed Central

    Wautier, J L; Wautier, M P; Schmidt, A M; Anderson, G M; Hori, O; Zoukourian, C; Capron, L; Chappey, O; Yan, S D; Brett, J

    1994-01-01

    Vascular complications are an important cause of morbidity and mortality in patients with diabetes. The extent of vascular complications has been linked statistically to enhanced adherence of diabetic erythrocytes to endothelial cells (ECs) and to the accumulation of a class of glycated proteins termed advanced glycation end products (AGEs). We hypothesized that formation of AGEs on the surface of diabetic erythrocytes could mediate their interaction with ECs leading to binding and induction of vascular dysfunction. Enhanced binding of diabetic erythrocytes to ECs was blocked by preincubation of erythrocytes with anti-AGE IgG or preincubation of ECs with antibodies to the receptor for AGE (RAGE). Immunoblotting of cultured human ECs and immunostaining of normal/diabetic human tissue confirmed the presence of RAGE in the vessel wall. Binding of diabetic erythrocytes to endothelium generated an oxidant stress, as measured by production of thiobarbituric acid-reactive substances (TBARS) and activation of the transcription factor NF-kappa B, both of which were blocked by probucol or anti-RAGE IgG. Erythrocytes from diabetic rats infused into normal rats had an accelerated, early phase of clearance that was prevented, in part, by antibody to RAGE. Liver tissue from rats infused with diabetic erythrocytes showed elevated levels of TBARS, which was prevented by pretreatment with anti-RAGE IgG or probucol. Thus, erythrocyte surface AGEs can function as ligands that interact with RAGE on endothelium. The extensive contact of diabetic erythrocytes bearing surface-associated AGEs with vessel wall RAGE could be important in the development of vascular complications. Images PMID:8052654

  13. Oligonol, a low-molecular-weight polyphenol derived from lychee fruit, attenuates diabetes-induced renal damage through the advanced glycation end product-related pathway in db/db mice.

    PubMed

    Park, Chan Hum; Yokozawa, Takako; Noh, Jeong Sook

    2014-08-01

    This study was conducted to examine whether oligonol, a low-molecular-weight polyphenol derived from lychee fruit, has an ameliorative effect on diabetes-induced alterations, such as advanced glycation end product (AGE) formation or apoptosis in the kidneys of db/db mice with type 2 diabetes. Oligonol [10 or 20 mg/(kg body weight · d), orally] was administered every day for 8 wk to prediabetic db/db mice, and its effect was compared with vehicle-treated db/db and normal control mice (m/m). The administration of oligonol decreased the elevated renal glucose concentrations and reactive oxygen species in db/db mice (P < 0.05). The increased serum urea nitrogen and creatinine concentrations, which reflect renal dysfunction in db/db mice, were substantially lowered by oligonol. Oligonol reduced renal protein expression of NAD(P)H oxidase subunits (p22 phagocytic oxidase and NAD(P)H oxidase-4), AGEs (except for pentosidine), and c-Jun N-terminal kinase B-targeting proinflammatory tumor necrosis factor-α (P < 0.05). Oligonol improved the expressions of antiapoptotic [B-cell lymphoma protein 2 (Bcl-2) and survivin] and proapoptotic [Bcl-2-associated X protein, cytochrome c, and caspase-3] proteins in the kidneys of db/db mice (P < 0.05). In conclusion, these results provide important evidence that oligonol exhibits a pleiotropic effect on AGE formation and apoptosis-related variables, representing renoprotective effects against the development of diabetic complications in db/db mice with type 2 diabetes.

  14. Morphological adaptation of muscle collagen and receptor of advanced glycation end product (RAGE) in osteoarthritis patients with 12 weeks of resistance training: influence of anti-inflammatory or glucosamine treatment.

    PubMed

    Mattiello-Sverzut, Ana Claudia; Petersen, Susanne G; Kjaer, Michael; Mackey, Abigail L

    2013-09-01

    The aim of this study was to investigate the effect of 12-week resistance training on morphological presence of collagen and RAGE (receptor for advanced glycation end products) in skeletal muscle of patients with knee osteoarthritis (OA). Little is known about the influence of exercise on the skeletal muscle matrix that supports joints affected by OA mainly when it is associated with medication taken by OA patients (non-steroid anti-inflammatory drugs (NSAID) and glucosamine). A biopsy was collected from the vastus lateralis muscle in all patients before and after 12-week period of training. The patients (age 55-69 years) were divided into three groups, treated with NSAID, glucosamine or placebo. In addition, the muscle samples were analysed by immunohistochemistry for collagen types, RAGE and capillaries ratio. An increment in immunoreactivity for type IV collagen after the training period was observed in 72 % of all biopsies when compared with their respective baseline samples. Reduced immunoreactivity of collagen type I was observed in all patients treated with glucosamine. A significant increase with training in the amount of RAGE was detected in the placebo group only (p < 0.05). Comparison of post-treatment states indicated significant differences between the placebo and glucosamine group data, demonstrating increased levels in the placebo group (p < 0.05). These findings suggest a basement membrane remodelling in favour of a strengthened extracellular matrix surrounding individual muscle fibres after 12 weeks of resistance training. Glucosamine with training appeared to attenuate RAGE accumulation more than was seen with NSAID or placebo in skeletal muscle of OA patients.

  15. 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

  16. 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.

  17. 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

  18. 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

  19. Effect of Circulating Soluble Receptor for Advanced Glycation End Products (sRAGE) and the Proinflammatory RAGE Ligand (EN-RAGE, S100A12) on Mortality in Hemodialysis Patients

    PubMed Central

    Nakashima, Ayumu; Qureshi, Abdul Rashid; Miyamoto, Tetsu; Anderstam, Björn; Bárány, Peter; Heimbürger, Olof; Stenvinkel, Peter; Lindholm, Bengt

    2010-01-01

    Background and objectives: The soluble receptor of advanced glycation end products (sRAGE) may exert anti-inflammatory protective roles on the vasculature. In contrast, the RAGE ligand S100A12 (also known as EN-RAGE) contributes to inflammation and the development of atherosclerosis in animal models. Whether alterations at this level contribute to the increased mortality observed in patients on dialysis is currently unknown. Design, setting, participants, & measurements: Prospective study including 184 prevalent hemodialysis patients and 50 healthy controls matched for age and gender. Plasma concentrations of S100A12 and sRAGE were studied in relation to risk profile and mortality after a median follow-up period of 41 months. Results: S100A12 and sRAGE levels were significantly elevated in hemodialysis patients compared with healthy controls. S100A12 had a strong positive correlation with C-reactive protein and IL-6, whereas sRAGE negatively associated with C-reactive protein. S100A12, but not sRAGE, was independently and positively associated with clinical cardiovascular disease (CVD). During follow-up, 85 (33 cardiovascular-related) deaths occurred. Whereas sRAGE did not predict mortality, S100A12 was associated with both all-cause (per log10 ng/ml hazard ratio [HR] 1.93, 95% confidence interval [CI] 1.18 to 3.15) and CVD-related (HR 3.23, 95% CI 1.48 to 7.01) mortality, even after adjustment for age, sex, vintage, and comorbidities. Further adjustment for inflammation made the predictive value of S100A12 disappear for all-cause mortality, but still persisted in CVD-related mortality. Conclusions: Circulating S100A12 and sRAGE are both elevated in hemodialysis patients. However, only S100A12 associates with mortality, partly explained by its links with inflammation. PMID:20847094

  20. 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.

  1. Evaluation of the antioxidant and anti-glication effects of the hexane extract from Piper auritum leaves in vitro and beneficial activity on oxidative stress and advanced glycation end-product-mediated renal injury in streptozotocin-treated diabetic rats.

    PubMed

    Perez Gutierrez, Rosa Martha; Flores Cotera, Luis B; Gonzalez, Adriana Maria Neira

    2012-10-09

    The aim of this study was to investigate the antioxidant activity of hexane extracts from leaves of Piper auritum (HS). Eight complementary in vitro test methods were used, including inhibition of DPPH· radicals, nitric oxide, superoxide anion, ion-chelating, ABTS, oxygen radical absorbance capacity, β-carotene bleaching and peroxy radical scavenging. The results indicated that HS possesses high antioxidant activity. To add to these finding we tested the effect against oxidative stress in liver, pancreas and kidney in diabetic rats. Low levels of SOD, CAT, GPx and GSH in diabetic rats were reverted to near normal values after treatment with HS. These results suggest that P. auritum prevents oxidative stress, acting as a suppressor of liver cell damage. Given the link between glycation and oxidation, we proposed that HS might possess significant in vitro antiglycation activity. Our data confirmed the inhibitory effect of HS on bovine serum albumin, serum glycosylated protein, glycation of LDL, and glycation hemoglobin. The effect of HS on diabetic renal damage was investigated using streptozotocin-induced diabetic rats. The oral administration of HS at a dose of 200 and 400 mg/kg body weight/day for 28 days significantly reduced advanced glycation endproduct (AGE) formation, elevated renal glucose and thiobarbituric acid-reactive substance levels in the kidneys of diabetic rats. This implies that HS would alleviate the oxidative stress under diabetes through the inhibition of lipid peroxidation. These findings indicate that oxidative stress is increased in the diabetic rat kidney and that HS can prevent renal damage associated with diabetes by attenuating the oxidative stress.

  2. 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

  3. 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

  4. 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

  5. Rapid and sensitive determination of the intermediates of advanced glycation end products in the human nail by ultra-performance liquid chromatography with electrospray ionization time-of-flight mass spectrometry.

    PubMed

    Min, Jun Zhe; Yamamoto, Makoto; Yu, Hai-fu; Higashi, Tatsuya; Toyo'oka, Toshimasa

    2012-05-15

    The resolution of the intermediate advanced glycation end products (AGEs) in the human nail was carried out by the combination of 4,5-dimethyl-1,2-phenylenediamine (DMPD) derivatives and ultra-performance liquid chromatography with electrospray ionization time-of-flight mass spectrometry (UPLC-ESI-TOF-MS). The reaction of the reagent with 3-deoxyglucosone (3-DG), methylglyoxal (MG), and glyoxal (GO) effectively proceeds at 60°C for 2h. The resulting derivatives were efficiently separated by a gradient program (a mixture of water and acetonitrile containing 0.1% formic acid) using a reversed-phase ACQUITY UPLC BEH C(18) column (1.7 μm, 50×2.1 mm i.d.) and sensitively detected by TOF-MS. The detection limits (signal-to-noise ratio=5) of the TOF-MS were 10 to 50 fmol. A good linearity was achieved from the calibration curve, which was obtained by plotting the peak area ratios of the analytes relative to the internal standard (IS) (i.e., 2,3-hexanedione) versus the injected amounts of 3-DG, MG, and GO (r(2)>0.999), and the intra- and interday assay precisions were less than 6.89%. The derivatives of the compounds in the human nail were successfully identified by the proposed procedure. As we know, these three kinds of dicarbonyl intermediates in the formation of AGEs-3-DG, MG, and GO-were first found in human nail samples. Using these methods, the amounts of compound in the nails of healthy volunteers and diabetic patients were determined. When comparing the index from the diabetic patients with that from healthy volunteers, there is no significant difference in the content of the MG and GO in the nails. However, a statistically significant (P<0.001) correlation was observed between the 3-DG concentrations. Because the proposed method provides a good mass accuracy and the trace detection of the dicarbonyl intermediates of AGEs in the human nail, this analytical technique could be a noninvasive technique to assist in the diagnosis and assessment of disease activity

  6. Golgi glycosylation.

    PubMed

    Stanley, Pamela

    2011-04-01

    Glycosylation is a very common modification of protein and lipid, and most glycosylation reactions occur in the Golgi. Although the transfer of initial sugar(s) to glycoproteins or glycolipids occurs in the ER or on the ER membrane, the subsequent addition of the many different sugars that make up a mature glycan is accomplished in the Golgi. Golgi membranes are studded with glycosyltransferases, glycosidases, and nucleotide sugar transporters arrayed in a generally ordered manner from the cis-Golgi to the trans-Golgi network (TGN), such that each activity is able to act on specific substrate(s) generated earlier in the pathway. The spectrum of glycosyltransferases and other activities that effect glycosylation may vary with cell type, and thus the final complement of glycans on glycoconjugates is variable. In addition, glycan synthesis is affected by Golgi pH, the integrity of Golgi peripheral membrane proteins, growth factor signaling, Golgi membrane dynamics, and cellular stress. Knowledge of Golgi glycosylation has fostered the development of assays to identify mechanisms of intracellular vesicular trafficking and facilitated glycosylation engineering of recombinant glycoproteins. PMID:21441588

  7. Glycosylated Metal Phthalocyanines.

    PubMed

    Hanack, Michael

    2015-11-10

    In the first part; the syntheses of mono-; di-; and tetra-glycosylated phthalonitriles is described; which are the most used starting materials for the preparation of the corresponding glycosylated metal (mostly zinc) phthalocyanines. In the second section; the preparation of symmetric and unsymmetric mono-; tetra-; and octa- glycosylated zinc phthalocyanines are reviewed; in which the sugar is attached to the phthalocyanine macrocycle; either anomerically or via another one of its OH-groups.

  8. 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

  9. A propos of glycosyl cations and the mechanism of chemical glycosylation; the current state of the art.

    PubMed

    Bohé, Luis; Crich, David

    2015-02-11

    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 counterion 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.

  10. 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

  11. Lactate is always the end product of glycolysis

    PubMed Central

    Rogatzki, Matthew J.; Ferguson, Brian S.; Goodwin, Matthew L.; Gladden, L. Bruce

    2015-01-01

    Through much of the history of metabolism, lactate (La−) has been considered merely a dead-end waste product during periods of dysoxia. Congruently, the end product of glycolysis has been viewed dichotomously: pyruvate in the presence of adequate oxygenation, La− in the absence of adequate oxygenation. In contrast, given the near-equilibrium nature of the lactate dehydrogenase (LDH) reaction and that LDH has a much higher activity than the putative regulatory enzymes of the glycolytic and oxidative pathways, we contend that La− is always the end product of glycolysis. Cellular La− accumulation, as opposed to flux, is dependent on (1) the rate of glycolysis, (2) oxidative enzyme activity, (3) cellular O2 level, and (4) the net rate of La− transport into (influx) or out of (efflux) the cell. For intracellular metabolism, we reintroduce the Cytosol-to-Mitochondria Lactate Shuttle. Our proposition, analogous to the phosphocreatine shuttle, purports that pyruvate, NAD+, NADH, and La− are held uniformly near equilibrium throughout the cell cytosol due to the high activity of LDH. La− is always the end product of glycolysis and represents the primary diffusing species capable of spatially linking glycolysis to oxidative phosphorylation. PMID:25774123

  12. 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

  13. 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,...

  14. 48 CFR 252.225-7022 - Trade agreements certificate-inclusion of Iraqi end products.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 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,...

  15. 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,...

  16. Chemical O‐Glycosylations: An Overview

    PubMed Central

    2016-01-01

    Abstract The development of glycobiology relies on the sources of particular oligosaccharides in their purest forms. As the isolation of the oligosaccharide structures from natural sources is not a reliable option for providing samples with homogeneity, chemical means become pertinent. The growing demand for diverse oligosaccharide structures has prompted the advancement of chemical strategies to stitch sugar molecules with precise stereo‐ and regioselectivity through the formation of glycosidic bonds. This Review will focus on the key developments towards chemical O‐glycosylations in the current century. Synthesis of novel glycosyl donors and acceptors and their unique activation for successful glycosylation are discussed. This Review concludes with a summary of recent developments and comments on future prospects. PMID:27777833

  17. 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

  18. Mammalian glycosylation in immunity

    PubMed Central

    Marth, Jamey D.; Grewal, Prabhjit K.

    2009-01-01

    Glycosylation produces a diverse and abundant repertoire of glycans, which are collectively known as the glycome. Glycans are one of the four fundamental macromolecular components of all cells, and are highly regulated in the immune system. Their diversity reflects their multiple biological functions that encompass ligands for proteinaceous of receptors known as lectins. Since the discovery that selectins and their glycan ligands are important for the regulation of leukocyte trafficking, it has been shown that additional features of the vertebrate immune system are also controlled by endogenous cellular glycosylation. This Review focuses on the emerging immunological roles of the mammalian glycome. PMID:18846099

  19. Association of end-product adducts with increased IgE binding of roasted peanuts.

    PubMed

    Chung, S Y; Champagne, E T

    2001-08-01

    Recently, we have shown that roasted peanuts have a higher level of IgE binding (i.e., potentially more allergenic) than raw peanuts. We hypothesized that this increase in IgE binding of roasted peanuts is due to an increased levels of protein-bound end products or adducts such as advanced glycation end products (AGE), N-(carboxymethyl)lysine (CML), malondialdehyde (MDA), and 4-hydroxynonenal (HNE). To support our hypothesis, we produced polyclonal antibodies (IgG) to each of these adducts, determined their levels in raw and roasted peanuts, and examined their ability to bind to IgE from a pooled serum of patients with clinically important peanut allergy. Results showed that AGE, CML, MDA, and HNE adducts were all present in raw and roasted peanuts. Roasted peanuts exhibited a higher level of AGE and MDA adducts than raw peanuts. IgE was partially inhibited in a competitive ELISA by antibodies to AGE but not by antibodies to CML, MDA, or HNE. This indicates that IgE has an affinity for peanut AGE adducts. Roasted peanuts exhibited a higher level of IgE binding, which was correlated with a higher level of AGE adducts. We concluded that there is an association between AGE adducts and increased IgE binding (i.e., allergenicity) of roasted peanuts.

  20. 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.

  1. Plant protein glycosylation

    PubMed Central

    Strasser, Richard

    2016-01-01

    Protein glycosylation is an essential co- and post-translational modification of secretory and membrane proteins in all eukaryotes. The initial steps of N-glycosylation and N-glycan processing are highly conserved between plants, mammals and yeast. In contrast, late N-glycan maturation steps in the Golgi differ significantly in plants giving rise to complex N-glycans with β1,2-linked xylose, core α1,3-linked fucose and Lewis A-type structures. While the essential role of N-glycan modifications on distinct mammalian glycoproteins is already well documented, we have only begun to decipher the biological function of this ubiquitous protein modification in different plant species. In this review, I focus on the biosynthesis and function of different protein N-linked glycans in plants. Special emphasis is given on glycan-mediated quality control processes in the ER and on the biological role of characteristic complex N-glycan structures. PMID:26911286

  2. Sulfide-mediated dehydrative glycosylation.

    PubMed

    Nguyen, H M; Chen, Y; Duron, S G; Gin, D Y

    2001-09-12

    The development of a new method for glycosylation with 1-hydroxy glycosyl donors employing dialkyl sulfonium reagents is described. The process employs the reagent combination of a dialkyl sulfide and triflic anhydride to effect anomeric bond constructions. This controlled dehydrative coupling of various C(1)-hemiacetal glycosyl donors and nucleophilic acceptors proceeds by way of a sulfide-to-sulfoxide oxidation process in which triflic anhydride serves as the oxidant.

  3. 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...

  4. 48 CFR 52.222-18 - Certification Regarding Knowledge of Child Labor for Listed End Products.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 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...

  5. 48 CFR 52.222-18 - Certification Regarding Knowledge of Child Labor for Listed End Products.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 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...

  6. 48 CFR 52.222-18 - Certification Regarding Knowledge of Child Labor for Listed End Products.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 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...

  7. 48 CFR 52.222-18 - Certification Regarding Knowledge of Child Labor for Listed End Products.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 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...

  8. Hallmarks of glycosylation in cancer

    PubMed Central

    Munkley, Jennifer; Elliott, David J.

    2016-01-01

    Aberrant glycosylation plays a fundamental role in key pathological steps of tumour development and progression. Glycans have roles in cancer cell signalling, tumour cell dissociation and invasion, cell-matrix interactions, angiogenesis, metastasis and immune modulation. Aberrant glycosylation is often cited as a ‘hallmark of cancer’ but is notably absent from both the original hallmarks of cancer and from the next generation of emerging hallmarks. This review discusses how glycosylation is clearly an enabling characteristic that is causally associated with the acquisition of all the hallmark capabilities. Rather than aberrant glycosylation being itself a hallmark of cancer, another perspective is that glycans play a role in every recognised cancer hallmark. PMID:27007155

  9. [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

  10. [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

  11. 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

  12. Microwave-assisted Maillard reactions for the preparation of advanced glycation end products (AGEs).

    PubMed

    Visentin, Sonja; Medana, Claudio; Barge, Alessandro; Giancotti, Valeria; Cravotto, Giancarlo

    2010-05-21

    The application of microwaves as an efficient form of volumetric heating to promote organic reactions was recognized in the mid-1980 s. It has a much longer history in the food research and industry where microwave irradiation was studied in depth to optimize food browning and the development of desirable flavours from Maillard reactions. The microwave-promoted Maillard reaction is a challenging synthetic method to generate molecular diversity in a straightforward way. In this paper we present a new rapid and efficient one-pot procedure for the preparation of pentosidine and other AGEs under microwave irradiation. PMID:20448908

  13. Reduction of serum advanced glycation end-products with a low calorie Mediterranean diet.

    PubMed

    Rodríguez, Juan Manuel; Leiva Balich, Laura; Concha, M J; Mizón, C; Bunout Barnett, Daniel; Barrera Acevedo, Gladys; Hirsch Birn, Sandra; Jiménez Jaime, Teresa; Henríquez, Sandra; Uribarri, Jaime; de la Maza Cave, María Pía

    2015-06-01

    La ingesta dietaria de productos finales de glicación avanzada (AGEs) aumenta los niveles séricos y tisulares de estas sustancias, lo que contribuye a un estado de mayor estrés oxidativo e inflamación. Una intervención dietaria con bajo contenido de AGEs ha demostrado reducir el contenido de AGEs en el cuerpo. La dieta mediterránea (DM) se considera teóricamente baja en AGEs, pero los efectos específicos de este tipo de intervención en los niveles séricos de AGEs no ha sido probado. Metodología: cuarenta y siete mujeres premenopáusicas con sobrepeso u obesidad se sometieron a tres meses de restricción calórica (20 kcal por kg de peso corporal inicial) con una dieta de tipo mediterráneo que excluía la ingesta de vino. La adherencia a la DM se evaluó al comienzo y al final del tratamiento utilizando una encuesta on-line, con puntuaciones de 0 a 14 (mínima a máxima adherencia a la DM). La composición corporal, la resistencia a la insulina, los niveles séricos de lipoproteínas y carboximetil-lisina (CML) se midieron en ambos períodos. El CML sérico se evaluó mediante ELISA (ensayo inmunoenzimático). La adherencia a la restricción calórica se evaluó de acuerdo con la pérdida de peso (< o > 5% del peso inicial). Resultados: la media de peso corporal, grasa corporal, circunferencia de la cintura, colesterol total, triglicéridos y CML sérica disminuyeron significativamente, junto con un aumento en el puntaje de adherencia a la DM, aunque ninguno de los pacientes alcanzó la máxima puntuación. Hubo cambios significativos en los niveles de CML y de resistencia a la insulina en 17 mujeres clasificadas como adherentes a la restricción calórica, pero no en las 27 participantes que fueron consideradas adherentes a la DM (de acuerdo con la mejoría en el puntaje de la encuesta). Conclusiones: los niveles séricos de CML disminuyeron tras la restricción calórica con una dieta tipo mediterránea. Dado que no se pudo alcanzar la puntuación máxima en la encuesta de DM, no podemos concluir si la propia DM tiene un efecto aditivo a la restricción calórica.

  14. 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

  15. Benzyne arylation of oxathiane glycosyl donors.

    PubMed

    Fascione, Martin A; Turnbull, W Bruce

    2010-01-01

    The arylation of bicyclic oxathiane glycosyl donors has been achieved using benzyne generated in situ from 1-aminobenzotriazole (1-ABT) and lead tetraacetate. Following sulfur arylation, glycosylation of acetate ions proceeded with high levels of stereoselectivity to afford α -glycosyl acetates in a 'one-pot' reaction, even in the presence of alternative acceptor alcohols.

  16. 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…

  17. Scavenger receptor of human monocytic leukemia cell line (THP-1) and murine macrophages for nonenzymatically glycosylated proteins.

    PubMed

    Takata, K; Horiuchi, S; Araki, N; Shiga, M; Saitoh, M; Morino, Y

    1989-11-17

    Long-term incubation of proteins with glucose undergo a series of nonenzymatic reactions to form advanced glycosylation end product (AGE) with fluorescence and brown color. The receptor for AGE-proteins was demonstrated in murine macrophages (Vlassara et al. (1985) Proc. Natl. Acad. Sci. USA 82. 5588). Our recent study with rat macrophages revealed that the receptor also recognized proteins modified with aliphatic aldehydes such as formaldehyde or glycolaldehyde, indicating its close identity to a scavenger receptor for aldehyde-modified proteins (Takata, K. et al. (1988) J. Biol. Chem. 263. 14819). This notion was tested in the present study with human monocytic leukemia cell line (THP-1 cells), human monocyte macrophages and murine peritoneal macrophages. Endocytic uptake of AGE-proteins and aldehyde-modified proteins was inhibited in a cross-competitive fashion. The receptor activities of THP-1 cells for AGE-albumin and aldehyde-modified proteins were induced synchronously by phorbol 12-myristate 13-acetate. Furthermore, upon reduction by NaBH4 of the Schiff base formed between proteins and glucose or aldehydes, no ligand activity was generated. However, once the ligand activity was generated, NaBH4 was no longer effective for the ligand activity. Thus, a structure in common between AGE-proteins and aldehyde-modified proteins may be crucial for recognition by the human macrophage receptor.

  18. Endocytic uptake of nonenzymatically glycosylated proteins is mediated by a scavenger receptor for aldehyde-modified proteins.

    PubMed

    Takata, K; Horiuchi, S; Araki, N; Shiga, M; Saitoh, M; Morino, Y

    1988-10-15

    Long term incubation of proteins with glucose, named the Maillard reaction (Maillard, L. C. (1912) C. R. Acad. Sci. (Paris) 154, 66-68), gives rise to advanced glycosylation end product (AGE) with fluorescence, color, as well as cross-linked properties. The receptor-mediated endocytosis of AGE-proteins by macrophages was reported (Vlassara, H., Brownlee, M., and Cerami, A. (1985) Proc. Natl. Acad. Sci. U.S.A. 82, 5588-5592). The present study on the binding of AGE-bovine serum albumin (BSA) to rat peritoneal macrophages and sinusoidal liver cells demonstrated the presence of a saturable, high affinity receptor for AGE-BSA with Kd = 2.4 x 10(-7) M (macrophages) and 2.1 x 10(-7) M (sinusoidal cells). The cellular binding of AGE-BSA and its endocytic uptake by these cells were competitively inhibited by BSA preparations modified with aliphatic aldehydes such as formaldehyde or glycolaldehyde, ligands known to be specific for a scavenger receptor for aldehyde-modified proteins (Horiuchi, S., Murakami, M., Takata, K., and Morino, Y. (1986). J. Biol. Chem. 261, 4962-4966). These ligands also had a profound in vivo effect on the plasma clearance of 125I-AGE-BSA as well as its hepatic uptake. Thus, endocytic uptake of AGE-proteins by macrophages appeared to be mediated by a scavenger receptor for aldehyde-modified proteins. This provides evidence for the biological importance of the scavenger receptor in eliminating senescent macromolecules from the circulation.

  19. 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

  20. 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

  1. 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.

  2. Marked increase in rat red blood cell membrane protein glycosylation by one-month treatment with a cafeteria diet.

    PubMed

    Oliva, Laia; Baron, Cristian; Fernández-López, José-Antonio; Remesar, Xavier; Alemany, Marià

    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

  3. Marked increase in rat red blood cell membrane protein glycosylation by one-month treatment with a cafeteria diet.

    PubMed

    Oliva, Laia; Baron, Cristian; Fernández-López, José-Antonio; Remesar, Xavier; Alemany, Marià

    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

  4. Total Synthesis of Glycosylated Proteins

    PubMed Central

    Brailsford, John; Zhang, Qiang; Shieh, Jae-Hung; Moore, Malcolm A.S.

    2016-01-01

    Glycoproteins are an important class of naturally occurring biomolecules which play a pivotal role in many biological processes. They are biosynthesized as complex mixtures of glycoforms through post-translational protein glycosylation. This fact, together with the challenges associated with producing them in homogeneous form, has hampered detailed structure-function studies of glycoproteins as well as their full exploitation as potential therapeutic agents. By contrast, chemical synthesis offers the unique opportunity to gain access to homogeneous glycoprotein samples for rigorous biological evaluation. Herein, we review recent methods for the assembly of complex glycopeptides and glycoproteins and present several examples from our laboratory towards the total chemical synthesis of clinically relevant glycosylated proteins that have enabled synthetic access to full-length homogeneous glycoproteins. PMID:25805144

  5. Progress in Yeast Glycosylation Engineering.

    PubMed

    Hamilton, Stephen R; Zha, Dongxing

    2015-01-01

    While yeast are lower eukaryotic organisms, they share many common features and biological processes with higher eukaryotes. As such, yeasts have been used as model organisms to facilitate our understanding of such features and processes. To this end, a large number of powerful genetic tools have been developed to investigate and manipulate these organisms. Going hand-in-hand with these genetic tools is the ability to efficiently scale up the fermentation of these organisms, thus making them attractive hosts for the production of recombinant proteins. A key feature of producing recombinant proteins in yeast is that these proteins can be readily secreted into the culture supernatant, simplifying any downstream processing. A consequence of this secretion is that the proteins typically pass through the secretory pathway, during which they may be exposed to various posttranslational modifications. The addition of glycans is one such modification. Unfortunately, while certain aspects of glycosylation are shared between lower and higher eukaryotes, significant differences exist. Over the last two decades much research has focused on engineering the glycosylation pathways of yeast to more closely resemble those of higher eukaryotes, particularly those of humans for the production of therapeutic proteins. In the current review we shall highlight some of the key achievements in yeast glyco-engineering which have led to humanization of both the N- and O-linked glycosylation pathways. PMID:26082216

  6. Metabolic Engineering of Escherichia coli for Production of Mixed-Acid Fermentation End Products

    PubMed Central

    Förster, Andreas H.; Gescher, Johannes

    2014-01-01

    Mixed-acid fermentation end products have numerous applications in biotechnology. This is probably the main driving force for the development of multiple strains that are supposed to produce individual end products with high yields. The process of engineering Escherichia coli strains for applied production of ethanol, lactate, succinate, or acetate was initiated several decades ago and is still ongoing. This review follows the path of strain development from the general characteristics of aerobic versus anaerobic metabolism over the regulatory machinery that enables the different metabolic routes. Thereafter, major improvements for broadening the substrate spectrum of E. coli toward cheap carbon sources like molasses or lignocellulose are highlighted before major routes of strain development for the production of ethanol, acetate, lactate, and succinate are presented. PMID:25152889

  7. 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

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. [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.

  13. 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.

  14. 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

  15. 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

  16. 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.

  17. Content of significant amounts of a cytotoxic end-product of lipid peroxidation in human semen.

    PubMed

    Selley, M L; Lacey, M J; Bartlett, M R; Copeland, C M; Ardlie, N G

    1991-07-01

    (E)-4-Hydroxy-2-nonenal (HNE), a cytotoxic end-product of lipid peroxidation, is present in significant amounts in human semen (0.902 +/- 0.190 microM; mean +/- s.e.; n = 18). The addition of the divalent cation ionophore A23187 to suspensions of human spermatozoa resulted in increased production of HNE. Exogenous HNE was powerfully spermicidal and as little as 50 microM caused an irreversible loss of motility of human spermatozoa within minutes. The addition of human seminal plasma protected spermatozoa from the toxic effects of HNE.

  18. Multidimensional fractionation is a requirement for quantitation of Golgi-resident glycosylation enzymes from cultured human cells.

    PubMed

    Lin, Chi-Hung; Chik, Jenny H L; Packer, Nicolle H; Molloy, Mark P

    2015-02-01

    Glycosylation results from the concerted action of glycosylation enzymes in the secretory pathway. In general, gene expression serves as the primary control mechanism, but post-translational fine-tuning of glycosylation enzyme functions is often necessary for efficient synthesis of specific glycan epitopes. While the field of glycomics has rapidly advanced, there lacks routine proteomic methods to measure expression of specific glycosylation enzymes needed to fill the gap between mRNA expression and the glycomic profile in a "reverse genomics" workflow. Toward developing this workflow we enriched Golgi membranes from two human colon cancer cell lines by sucrose density centrifugation and further mass-based fractionation by SDS-PAGE. We then applied mass spectrometry to demonstrate a doubling in the number of Golgi resident proteins identified, compared to the unenriched, low speed centrifuged supernatant of lysed cells. A total of 35 Golgi-resident glycosylation enzymes, of which 23 were glycosyltransferases, were identified making this the largest protein database so far of Golgi resident glycosylation enzymes experimentally identified in cultured human cells. We developed targeted mass spectrometry assays for specific quantitation of many of these glycosylation enzymes. Our results show that alterations in abundance of glycosylation enzymes at the protein level were generally consistent with the resultant glycomic profiles, but not necessarily with the corresponding glycosyltransferase mRNA expression as exemplified by the case of O-glycan core 1 T synthase.

  19. Pharmacy component of a hospital end-product cost-accounting system.

    PubMed

    Smith, J E; Sheaffer, S L; Meyer, G E; Giorgilli, F

    1988-04-01

    Determination of pharmacy department standard costs for providing drug products to patients at Thomas Jefferson University Hospital in Philadelphia is described. The hospital is implementing a cost-accounting system (CAS) that uses software developed at the New England Medical Center, Boston. The pharmacy identified nine categories of intermediate products on the basis of labor consumption. Standard labor times for each product category are based on measurement or estimation of time for each task in the preparation and distribution of a dose. Variable-labor standard time was determined by adjusting the cumulative time for the tasks to account for nonproductive time and nonroutine activities, and a variable-labor standard cost for each category was calculated. The standard cost per dose included the costs of labor and supplies (variable and fixed) and equipment; this standard cost plus the acquisition cost of a drug line item is the total intermediate product cost. Because the CAS is based on the hospital's patient charges, clinical pharmacy services are excluded. Intermediate products that substantially affect end-product costs (costs per patient case) will be identified for inclusion in CAS reports. The CAS will give a more accurate picture of resource consumption, enabling managers to focus their efforts to improve efficiency and productivity and reduce supply use; it could also improve the accuracy of the budgeting process. The CAS will support hospital administration decisions about marketing end products and department managers' decisions about controlling intermediate-product costs.

  20. 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.

  1. 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

  2. Germanium recovery from gasification fly ash: evaluation of end-products obtained by precipitation methods.

    PubMed

    Arroyo, Fátima; Font, Oriol; Fernández-Pereira, Constantino; Querol, Xavier; Juan, Roberto; Ruiz, Carmen; Coca, Pilar

    2009-08-15

    In this study the purity of the germanium end-products obtained by two different precipitation methods carried out on germanium-bearing solutions was evaluated as a last step of a hydrometallurgy process for the recovery of this valuable element from the Puertollano Integrated Gasification Combined Cycle (IGCC) fly ash. Since H(2)S is produced as a by-product in the gas cleaning system of the Puertollano IGCC plant, precipitation of germanium as GeS(2) was tested by sulfiding the Ge-bearing solutions. The technological and hazardous issues that surround H(2)S handling conducted to investigate a novel precipitation procedure: precipitation as an organic complex by adding 1,2-dihydroxy benzene pyrocatechol (CAT) and cetyltrimethylammonium bromide (CTAB) to the Ge-bearing solutions. Relatively high purity Ge end-products (90 and 93% hexagonal-GeO(2) purity, respectively) were obtained by precipitating Ge from enriched solutions, as GeS(2) sulfiding the solutions with H(2)S, or as organic complex with CAT/CTAB mixtures and subsequent roasting of the precipitates. Both methods showed high efficiency (>99%) to precipitate selectively Ge using a single precipitation stage from germanium-bearing solutions.

  3. Pharmacy component of a hospital end-product cost-accounting system.

    PubMed

    Smith, J E; Sheaffer, S L; Meyer, G E; Giorgilli, F

    1988-04-01

    Determination of pharmacy department standard costs for providing drug products to patients at Thomas Jefferson University Hospital in Philadelphia is described. The hospital is implementing a cost-accounting system (CAS) that uses software developed at the New England Medical Center, Boston. The pharmacy identified nine categories of intermediate products on the basis of labor consumption. Standard labor times for each product category are based on measurement or estimation of time for each task in the preparation and distribution of a dose. Variable-labor standard time was determined by adjusting the cumulative time for the tasks to account for nonproductive time and nonroutine activities, and a variable-labor standard cost for each category was calculated. The standard cost per dose included the costs of labor and supplies (variable and fixed) and equipment; this standard cost plus the acquisition cost of a drug line item is the total intermediate product cost. Because the CAS is based on the hospital's patient charges, clinical pharmacy services are excluded. Intermediate products that substantially affect end-product costs (costs per patient case) will be identified for inclusion in CAS reports. The CAS will give a more accurate picture of resource consumption, enabling managers to focus their efforts to improve efficiency and productivity and reduce supply use; it could also improve the accuracy of the budgeting process. The CAS will support hospital administration decisions about marketing end products and department managers' decisions about controlling intermediate-product costs. PMID:3376968

  4. 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

  5. Glycosylation-Based Serum Biomarkers for Cancer Diagnostics and Prognostics.

    PubMed

    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.

  6. Glycosylation site occupancy in health, congenital disorder of glycosylation and fatty liver disease

    PubMed Central

    Hülsmeier, Andreas J.; Tobler, Micha; Burda, Patricie; Hennet, Thierry

    2016-01-01

    Glycosylation is an integral part in health and disease, as emphasized by the growing number of identified glycosylation defects. In humans, proteins are modified with a diverse range of glycoforms synthesized in complex biosynthetic pathways. Glycosylation disorders have been described in congenital disorders of glycosylation (CDG) as well as in acquired disease conditions such and non-alcoholic fatty liver disease (NAFLD). A hallmark in a subset of CDG cases is the reduced glycosylation site occupancy of asparagine-linked glycans. Using an optimized method protocol, we determined the glycosylation site occupancy from four proteins of hepatic and lymphatic origin from CDG and NAFLD patients. We found variable degrees of site occupancy, depending on the tissue of origin and the disease condition. In CDG glycosylation sites of IgG2 and IgA1 were occupied to normal levels. In NAFLD haptoglobin and transferrin glycosylation sites were hyper-glycosylated, a property qualifying for its use as a potential biomarker. Furthermore, we observed, that glycosylation sites of liver-originating transferrin and haptoglobin are differentially occupied under physiological conditions, a further instance not noticed in serum proteins to date. Our findings suggest the use of serum protein hyperglycosylation as a biomarker for early stages of NAFLD. PMID:27725718

  7. Glycosylation of Fluorophenols by Plant Cell Cultures

    PubMed Central

    Shimoda, Kei; Kubota, Naoji; Kondo, Yoko; Sato, Daisuke; Hamada, Hiroki

    2009-01-01

    Fluoroaromatic compounds are used as agrochemicals and released into environment as pollutants. Glycosylation of 2-, 3-, and 4-fluorophenols using plant cell cultures of Nicotiana tabacum was investigated to elucidate their potential to metabolize these compounds. Cultured N. tabacum cells converted 2-fluorophenol into its β-glucoside (60%) and β-gentiobioside (10%). 4-Fluorophenol was also glycosylated to its β-glucoside (32%) and β-gentiobioside (6%) by N. tabacum cells. On the other hand, N. tabacum glycosylated 3-fluorophenol to β-glucoside (17%). PMID:19564930

  8. Glycosylation and Activities of Natural Products.

    PubMed

    Huang, Gangliang; Lv, Meijiao; Hu, Jinchuan; Huang, Kunlin; Xu, Hong

    2016-01-01

    Natural products are widely found in nature, their number and variety are numerous, the structures are complex and diverse. These natural products have many physiological and pharmacological activities. Glycosylation can increase the diversity of structure and function of natural product, it has become the focus of drug research and development. The impacts of glycosylation of natural products to water solubility, pharmacological activities, bioavailability, or others were described in this review, which provides a reference for the development and application of glycosylated natural products. PMID:27499190

  9. SOLUBLE HEPATIC δ-AMINOLEVULINIC ACID SYNTHETASE: END-PRODUCT INHIBITION OF THE PARTIALLY PURIFIED ENZYME*

    PubMed Central

    Scholnick, Perry L.; Hammaker, Lydia E.; Marver, Harvey S.

    1969-01-01

    The present study confirms the existence of hepatic δ-aminolevulinic acid synthetase in the cytosol of the liver, suggests that this enzyme may be in transit to the mitochondria, and defines some of the characteristics of the partially purified enzyme. The substrate and cofactor requirements are similar to those of mitochondrial δ-aminolevulinic acid synthetase. Heme strongly inhibits the partially purified enzyme. A number of proteins that bind heme block this inhibition, which explains previous failures to demonstrate heme inhibition in crude systems. End-product inhibition of δ-aminolevulinic acid synthetase in the mitochondria may play an important role in the regulation of heme biosynthesis in eukaryotic cells. PMID:5257968

  10. 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.

  11. 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.

  12. Exploring human glycosylation for better therapies.

    PubMed

    Krasnova, Larissa; Wong, Chi-Huey

    2016-10-01

    Glycosylation of lipids and proteins is not encoded by genes directly and depends on many factors including the origin of cell-lines, differential expression of carbohydrate enzymes and availability of substrates, as well as environmental conditions. Individual cells from different tissues produce each glycoprotein as heterogeneous mixtures of glycoforms with distinct biological activities in response to different conditions and disease states. As the result, the study of glycosylation could not rely purely on biochemical methods; instead it requires a multidisciplinary approach utilizing a variety of methods including genetic manipulation and glycosylation pathway engineering, structural and functional proteomic analysis, chemical and enzymatic synthesis, development of glycosylation probes and glycan microarrays. This review highlights recent progress and demonstrates how the availability of structure-defined oligosaccharides enables development of new and improved therapies, such as therapeutic homogeneous antibodies and carbohydrate-based vaccines against cancer. PMID:27178988

  13. 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

  14. 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

  15. Glycosylation of the nuclear pore

    PubMed Central

    Li, Bin; Kohler, Jennifer J.

    2014-01-01

    The O-linked β-N-acetylglucosamine (O-GlcNAc) post-translational modification was first discovered thirty years ago and is highly concentrated in the nuclear pore. In the years since the discovery of this single sugar modification, substantial progress has been made in understanding the biochemistry of O-GlcNAc and its regulation. Nonetheless, O-GlcNAc modification of proteins continues to be overlooked, due in large part to the lack of reliable methods available for its detection. Recently, a new crop of immunological and chemical detection reagents has changed the research landscape. Using these tools, approximately 1000 O-GlcNAc-modified proteins have been identified. While other forms of glycosylation are typically associated with extracellular proteins, O-GlcNAc is abundant on nuclear and cytoplasmic proteins. In particular, phenylalanine-glycine (FG) nucleoporins (NUPs) are heavily O-GlcNAc-modified. Recent experiments are beginning to provide insight into the functional implications of O-GlcNAc modification on certain proteins, but its role in the nuclear pore has remained enigmatic. However, tantalizing new results suggest that O-GlcNAc may play roles in regulating nucleocytoplasmic transport. PMID:24423194

  16. N-/O-glycosylation analysis of human FVIIa produced in the milk of transgenic rabbits.

    PubMed

    Chevreux, Guillaume; Faid, Valegh; Scohyers, Jean-Marc; Bihoreau, Nicolas

    2013-12-01

    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 A(2)G(2)S(1). 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.

  17. 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

  18. Strategies to reduce end-product inhibition in family 48 glycoside hydrolases

    DOE PAGES

    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

  19. 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

  20. 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

  1. 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.

  2. Methods for improving enzymatic trans-glycosylation for synthesis of human milk oligosaccharide biomimetics.

    PubMed

    Zeuner, Birgitte; Jers, Carsten; Mikkelsen, Jørn Dalgaard; Meyer, Anne S

    2014-10-01

    Recently, significant progress has been made within enzymatic synthesis of biomimetic, functional glycans, including, for example, human milk oligosaccharides. These compounds are mainly composed of N-acetylglucosamine, fucose, sialic acid, galactose, and glucose, and their controlled enzymatic synthesis is a novel field of research in advanced food ingredient chemistry, involving the use of rare enzymes, which have until now mainly been studied for their biochemical significance, not for targeted biosynthesis applications. For the enzymatic synthesis of biofunctional glycans reaction parameter optimization to promote "reverse" catalysis with glycosidases is currently preferred over the use of glycosyl transferases. Numerous methods exist for minimizing the undesirable glycosidase-catalyzed hydrolysis and for improving the trans-glycosylation yields. This review provides an overview of the approaches and data available concerning optimization of enzymatic trans-glycosylation for novel synthesis of complex bioactive carbohydrates using sialidases, α-l-fucosidases, and β-galactosidases as examples. The use of an adequately high acceptor/donor ratio, reaction time control, continuous product removal, enzyme recycling, and/or the use of cosolvents may significantly improve trans-glycosylation and biocatalytic productivity of the enzymatic reactions. Protein engineering is also a promising technique for obtaining high trans-glycosylation yields, and proof-of-concept for reversing sialidase activity to trans-sialidase action has been established. However, the protein engineering route currently requires significant research efforts in each case because the structure-function relationship of the enzymes is presently poorly understood.

  3. Reduced Plasma Nitric Oxide End Products in Cocaine-dependent Men.

    PubMed

    Kaufman, Marc J; Streeter, Chris C; Barros, Tanya L; Sarid-Segal, Ofra; Afshar, Maryam; Tian, Hua; Rouse, Elizabeth D; Foy, Karen K B; Brimson, Melanie L; Archambault, Courtney A; Renshaw, Perry F; Ciraulo, Domenic A

    2007-06-01

    Chronic cocaine abusers experience brain and peripheral vascular dysfunction, the severity of which tends to be greater in men than women. The mechanisms underlying these effects of cocaine are unknown. Because nitric oxide (NO) abnormalities play key roles in development of vascular dysfunction in several disorders, we determined whether vascular nitric oxide end product (NOx) levels, which can serve as markers of systemic vascular NO production, are reduced in cocaine-dependent (CD) subjects. Plasma samples from 24 CD men, 12 CD women, and matched comparison subjects (19 men, 14 women) were analyzed with a Sievers 280i nitric oxide chemiluminescence detection analysis system. NOx levels in comparison in women and men were 24.9 ± 6.6 and 23.3 ± 5.7 μmol/L, and in CD women and men were 22.5 ± 8.4 and 13.0 ± 9.6 μmol/L, respectively. ANCOVA analysis, adjusted for lifetime smoking, indicated group (P < 0.0005) and sex (P = 0.04) effects, both of which survived posthoc Scheffe tests. Reduced NOx levels in CD men drove the group difference. These data suggest that chronic cocaine abuse is associated with reduced NOx levels in men, although the finding also may be attributable to factors indirectly related to cocaine abuse, including cohort differences in other drug use or lifestyle factors. These findings warrant additional studies to more directly characterize vascular NO turnover in cocaine abusers and to establish whether NO abnormalities contribute to cocaine-associated vascular dysfunction and to sex differences in cocaine's effects. PMID:21768941

  4. 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

  5. Cloning, characterisation, and comparative quantitative expression analyses of receptor for advanced glycation end products (RAGE) transcript forms.

    PubMed

    Sterenczak, Katharina A; Willenbrock, Saskia; Barann, Matthias; Klemke, Markus; Soller, Jan T; Eberle, Nina; Nolte, Ingo; Bullerdiek, Jörn; Murua Escobar, Hugo

    2009-04-01

    RAGE is a member of the immunoglobulin superfamily of cell surface molecules playing key roles in pathophysiological processes, e.g. immune/inflammatory disorders, Alzheimer's disease, diabetic arteriosclerosis and tumourigenesis. In humans 19 naturally occurring RAGE splicing variants resulting in either N-terminally or C-terminally truncated proteins were identified and are lately discussed as mechanisms for receptor regulation. Accordingly, deregulation of sRAGE levels has been associated with several diseases e.g. Alzheimer's disease, Type 1 diabetes, and rheumatoid arthritis. Administration of recombinant sRAGE to animal models of cancer blocked tumour growth successfully. In spite of its obvious relationship to cancer and metastasis data focusing sRAGE deregulation and tumours is rare. In this study we screened a set of tumours, healthy tissues and various cancer cell lines for RAGE splicing variants and analysed their structure. Additionally, we analysed the ratio of the mainly found transcript variants using quantitative Real-Time PCR. In total we characterised 24 previously not described canine and 4 human RAGE splicing variants, analysed their structure, classified their characteristics, and derived their respective protein forms. Interestingly, the healthy and the neoplastic tissue samples showed in majority RAGE transcripts coding for the complete receptor and transcripts showing insertions of intron 1. PMID:19061941

  6. Oligomeric procyanidins of lotus seedpod inhibits the formation of advanced glycation end-products by scavenging reactive carbonyls.

    PubMed

    Wu, Qian; Chen, Hengye; Lv, Zhejuan; Li, Shuyi; Hu, Bei; Guan, Yafei; Xie, Bijun; Sun, Zhida

    2013-06-01

    It has been reported that oligomeric procyanidins of lotus seedpod (LSOPC) is effective in the alleviation of Alzheimer's disease and diabetes through its antioxidant and insulin-potentiating activities. This study investigated the anti-glycative activity of LSOPC in a bovine serum albumin (BSA)-glucose model. The level of glycation and conformational alterations were assessed by specific fluorescence, Congo red binding assay and circular dichroism. The results show that LSOPC has a significant anti-glycative activity in vitro and it can also effectively protect the secondary structure of BSA during glycation. LSOPC or catechin (a major constituent unit of LSOPC), were used to react with methylglyoxal. The structures of their carbonyl adducts were tentatively identified using HPLC-MS(2). Their capacity to scavenge methylglyoxal suggested carbonyl scavenging as a major mechanism of antiglycation. Therefore, LSOPC could be helpful to prevent AGEs-associated diseases, and with the potential to be used as functional food ingredients.

  7. Hafnium(IV) tetratriflate as a glycosyl fluoride activation reagent.

    PubMed

    Manabe, Shino; Ito, Yukishige

    2013-05-01

    Hafnium(IV) tetratriflate was found to be a good activator of glycosyl fluoride. The protocol was operationally simple and was widely applicable to a variety of substrates in both solid-phase and solution-phase glycosylation reactions.

  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

    ... Child Labor. 622.1503 Section 622.1503 Federal Acquisition Regulations System DEPARTMENT OF STATE... 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, 2012 CFR

    2012-10-01

    ... Child Labor. 22.1503 Section 22.1503 Federal Acquisition Regulations System FEDERAL ACQUISITION... 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 22.1503 - Procedures for acquiring end products on the List of Products Requiring Contractor Certification...

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... Child Labor. 22.1503 Section 22.1503 Federal Acquisition Regulations System FEDERAL ACQUISITION... 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...

  11. 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

    ... Child Labor. 622.1503 Section 622.1503 Federal Acquisition Regulations System DEPARTMENT OF STATE... 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

    ... Child Labor. 22.1503 Section 22.1503 Federal Acquisition Regulations System FEDERAL ACQUISITION... 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 22.1503 - Procedures for acquiring end products on the List of Products Requiring Contractor Certification...

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... Child Labor. 22.1503 Section 22.1503 Federal Acquisition Regulations System FEDERAL ACQUISITION... 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...

  14. 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

    ... Child Labor. 22.1503 Section 22.1503 Federal Acquisition Regulations System FEDERAL ACQUISITION... 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, 2011 CFR

    2011-10-01

    ... Child Labor. 622.1503 Section 622.1503 Federal Acquisition Regulations System DEPARTMENT OF STATE... 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 622.1503 - Procedures for acquiring end products on the List of Products Requiring Contractor Certification...

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... Child Labor. 622.1503 Section 622.1503 Federal Acquisition Regulations System DEPARTMENT OF STATE... 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)...

  17. 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

    ... Child Labor. 622.1503 Section 622.1503 Federal Acquisition Regulations System DEPARTMENT OF STATE... 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)...

  18. Glycosyl Thioimidates as Versatile Building Blocks for Organic Synthesis

    PubMed Central

    Hasty, S. J.

    2013-01-01

    This review discusses the synthesis and application of glycosyl thioimidates in chemical glycosylation and oligosaccharide assembly. Although glycosyl thioimidates include a broad range of compounds, the discussion herein centers on S-benzothiazolyl (SBaz), S-benzoxazolyl (SBox), S-thiazolinyl (STaz), and S-benzimidazolyl (SBiz) glycosides. These heterocyclic moieties have recently emerged as excellent anomeric leaving groups that express unique characteristics for highly diastereoselective glycosylation and help to provide the streamlined access to oligosaccharides. PMID:24288416

  19. 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

  20. Protein glycosylation--an evolutionary crossroad between genes and environment.

    PubMed

    Lauc, Gordan; Zoldoš, Vlatka

    2010-12-01

    The majority of molecular processes in higher organisms are performed by various proteins and are thus determined by genes that encode these proteins. However, a significant structural component of at least half of all cellular proteins is not a polypeptide encoded by a single gene, but an oligosaccharide (glycan) synthesized by a network of proteins, resulting from the expression of hundreds of different genes. Relationships between hundreds of individual proteins that participate in glycan biosynthesis are very complex which enables the influence of environmental factors on the final structure of glycans, either by direct effects on individual enzymatic processes, or by induction of epigenetic changes that modify gene expression patterns. Until recently, the complexity of glycan structures prevented large scale studies of protein glycosylation, but recent advances in both glycan analysis and genotyping technologies, enabled the first insights into the intricate field of complex genetics of protein glycosylation. Mutations which inactivate genes involved in the synthesis of common N-glycan precursors are embryonically lethal. However, mutations in genes involved in modifications of glycan antennas are common and apparently contribute largely to individual phenotypic variations that exist in humans and other higher organisms. Some of these variations can be recognized as specific glyco-phenotypes that might represent specific evolutionary advantages or disadvantages. They are however, amenable to environmental influences and are thus less pre-determined than classical Mendelian mutations.

  1. 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

  2. Genome-wide evolutionary conservation of N-glycosylation sites.

    PubMed

    Park, Chungoo; Zhang, Jianzhi

    2011-08-01

    Although posttranslational protein modifications are generally thought to perform important cellular functions, recent studies showed that a large fraction of phosphorylation sites are not evolutionarily conserved. Whether the same is true for other protein modifications, such as N-glycosylation is an open question. N-glycosylation is a form of cotranslational and posttranslational modification that occurs by enzymatic addition of a polysaccharide, or glycan, to an asparagine (N) residue of a protein. Examining a large set of experimentally determined mouse N-glycosylation sites, we find that the evolutionary rate of glycosylated asparagines is significantly lower than that of nonglycosylated asparagines of the same proteins. We further confirm that the conservation of glycosylated asparagines is accompanied by the conservation of the canonical motif sequence for glycosylation, suggesting that the above substitution rate difference is related to glycosylation. Interestingly, when solvent accessibility is considered, the substitution rate disparity between glycosylated and nonglycosylated asparagines is highly significant at solvent accessible sites but not at solvent inaccessible sites. Thus, although the solvent inaccessible glycosylation sites were experimentally identified, they are unlikely to be genuine or physiologically important. For solvent accessible asparagines, our analysis reveals a widespread and strong functional constraint on glycosylation, unlike what has been observed for phosphorylation sites in most studies, including our own analysis. Because the majority of N-glycosylation occurs at solvent accessible sites, our results show an overall functional importance for N-glycosylation.

  3. 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

  4. 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

  5. Neurologic course of congenital disorders of glycosylation.

    PubMed

    Pearl, P L; Krasnewich, D

    2001-06-01

    Congenital disorders of glycosylation, formerly called carbohydrate-deficient glycoprotein syndrome, may present in infancy with slowly progressive neurologic deficits including cognitive impairment, ataxia, pigmentary retinal degeneration, and neuropathy. The metabolic defect is in N-linked oligosaccharide synthesis, and diagnosis is made by a serum transferrin isoelectric focusing. We reviewed the neurologic course of 10 children with congenital disorders of glycosylation (ages 13 months to 7 years). All had severe developmental delay and ataxia; none walked unassisted, and the highest level of communication was simple sign language in one patient. Five of 10 children had seizures (absence, complex partial, tonic clonic). Only one patient has had strokelike episodes, despite reports that they are common in this population. The underlying basis of these episodes has been hypothesized to be coagulopathy due to dysfunctional, incorrectly glycosylated coagulation factors. This 5-year-old patient with congenital disorders of glycosylation type Ia had two strokelike episodes, with evolving hemiparesis over 5 to 6 days' duration, followed by focal tonic-clonic seizures. Coagulation studies were normal. Electroencephalography showed transient hemispheric polymorphous delta-range slowing and suppression. Magnetic resonance imaging revealed corresponding cortical swelling. Magnetic resonance angiography was normal. Magnetic resonance spectroscopy revealed a decrease in the N-acetylaspartate peak, suggesting neuronal loss, with normal lactate peak. The neuroradiologic data do not support a thrombotic, embolic, or hemorrhagic basis for strokelike episodes in carbohydrate-deficient glycoprotein syndrome; other mechanisms must be considered.

  6. Surface Glycosylation Profiles of Urine Extracellular Vesicles

    PubMed Central

    Gerlach, Jared Q.; Krüger, Anja; Gallogly, Susan; Hanley, Shirley A.; Hogan, Marie C.; Ward, Christopher J.

    2013-01-01

    Urinary extracellular vesicles (uEVs) are released by cells throughout the nephron and contain biomolecules from their cells of origin. Although uEV-associated proteins and RNA have been studied in detail, little information exists regarding uEV glycosylation characteristics. Surface glycosylation profiling by flow cytometry and lectin microarray was applied to uEVs enriched from urine of healthy adults by ultracentrifugation and centrifugal filtration. The carbohydrate specificity of lectin microarray profiles was confirmed by competitive sugar inhibition and carbohydrate-specific enzyme hydrolysis. Glycosylation profiles of uEVs and purified Tamm Horsfall protein were compared. In both flow cytometry and lectin microarray assays, uEVs demonstrated surface binding, at low to moderate intensities, of a broad range of lectins whether prepared by ultracentrifugation or centrifugal filtration. In general, ultracentrifugation-prepared uEVs demonstrated higher lectin binding intensities than centrifugal filtration-prepared uEVs consistent with lesser amounts of co-purified non-vesicular proteins. The surface glycosylation profiles of uEVs showed little inter-individual variation and were distinct from those of Tamm Horsfall protein, which bound a limited number of lectins. In a pilot study, lectin microarray was used to compare uEVs from individuals with autosomal dominant polycystic kidney disease to those of age-matched controls. The lectin microarray profiles of polycystic kidney disease and healthy uEVs showed differences in binding intensity of 6/43 lectins. Our results reveal a complex surface glycosylation profile of uEVs that is accessible to lectin-based analysis following multiple uEV enrichment techniques, is distinct from co-purified Tamm Horsfall protein and may demonstrate disease-specific modifications. PMID:24069349

  7. Glycosyl trifluoroacetimidates. 2. Synthesis of dioscin and xiebai saponin I.

    PubMed

    Yu, Biao; Tao, Houchao

    2002-12-13

    Two trisaccharide steroidal saponins, dioscin (1) and Xiebai saponin I (2) with various bioactivities, were efficiently synthesized using the newly developed glycosyl N-phenyl trifluoroacetimidates (10-13) as glycosylation donors. Thus, dioscin was synthesized in five steps and a 33% overall yield from diosgenin and glycosyl trifluoroacetimidates (10 and 11). Xiebai saponin I was synthesized in eight steps and a 32% overall yield from laxogenin and glycosyl trifluoroacetimidates (10, 12, and 13), whereupon, the rare steroid laxogenin was prepared from diosgenin in four steps and an overall 69% yield. All the glycosylation reactions involved in the present syntheses demonstrated that glycosyl trifluoroacetimidates were successful donors comparable to the corresponding glycosyl trichloroacetimidates. PMID:12467439

  8. 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

  9. 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.

  10. 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

  11. 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

  12. Lactonization-mediated glycosylations and their application to oligosaccharide synthesis.

    PubMed

    Kim, Kwan Soo; Jeon, Heung Bae

    2008-01-01

    The concept of lactonization-mediated and related glycosylations led us to develop new methods of glycosylation such as the 2'-carboxybenzyl (CB) glycoside method, the glycosyl pentenoate/phenylselenyl trifluoromethanesulfonate (PhSeOTf) method, and the glycosyl aryl phthalate method. Highly stereoselective beta-mannopyranosylations were achieved by employing the CB glycoside and the glycosyl pentenoate/PhSeOTf methods. The CB glycoside method was also utilized for stereoselective 2-deoxyglycosylation, beta-arabinofuranosylation, and alpha-galactofuranosylation. In addition, these lactonization-mediated methods of glycosylation were employed for the synthesis of complex oligosaccharides. In particular, the CB glycoside method was successfully applied to the synthesis of repeating oligosaccharide subunits of the O-polysaccharide of the lipopolysaccharide from Danish Helicobacter pylori strains and Escherichia coli 077, the synthesis of oligoarabinofuranosides in mycobacterial cell walls, and the total synthesis of antineoplastic agelagalastatin. PMID:18302265

  13. [Congenital disorder of glycosylation type Ia (CDG Ia) - underdiagnosed entity?].

    PubMed

    Sätilä, Heli; Kuusela, Anna-Leena; Pietilä, Kati; Niinikoski, Harri; Keskinen, Päivi

    2016-01-01

    Congenital disorders of glycosylation (CDG) are a relatively recently identified group of multisystem disorders caused by defective glycosylation of N-glycosylated proteins. They mainly involve the central and peripheral nervous system, but other organ systems are involved as well. Type CDG Ia accounts for over 80% of cases, characterized by decreased activity of the enzyme phosphomannomutase caused by mutations in chromosome 16 PMM2 gene. Treatment of CDG Ia remains symptomatic.

  14. 21 CFR 864.7470 - Glycosylated hemoglobin assay.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 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)....

  15. 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)....

  16. 21 CFR 864.7470 - Glycosylated hemoglobin assay.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 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)....

  17. 21 CFR 864.7470 - Glycosylated hemoglobin assay.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 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)....

  18. 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)....

  19. 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

  20. 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.

  1. 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

  2. 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.

  3. Chemical approaches to understanding O-GlcNAc glycosylation in the brain

    PubMed Central

    Rexach, Jessica E; Clark, Peter M; Hsieh-Wilson, Linda C

    2011-01-01

    O -GlcNAc glycosylation is a unique, dynamic form of glycosylation found on intracellular proteins of all multicellular organisms. Studies suggest that O-GlcNAc represents a key regulatory modification in the brain, contributing to transcriptional regulation, neuronal communication and neurodegenerative disease. Recently, several new chemical tools have been developed to detect and study the modification, including chemoenzymatic tagging methods, quantitative proteomics strategies and small-molecule inhibitors of O-GlcNAc enzymes. Here we highlight some of the emerging roles for O-GlcNAc in the nervous system and describe how chemical tools have significantly advanced our understanding of the scope, functional significance and cellular dynamics of this modification. PMID:18202679

  4. 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

  5. Altered Tumor-Cell Glycosylation Promotes Metastasis

    PubMed Central

    Häuselmann, Irina; Borsig, Lubor

    2014-01-01

    Malignant transformation of cells is associated with aberrant glycosylation presented on the cell-surface. Commonly observed changes in glycan structures during malignancy encompass aberrant expression and glycosylation of mucins; abnormal branching of N-glycans; and increased presence of sialic acid on proteins and glycolipids. Accumulating evidence supports the notion that the presence of certain glycan structures correlates with cancer progression by affecting tumor-cell invasiveness, ability to disseminate through the blood circulation and to metastasize in distant organs. During metastasis tumor-cell-derived glycans enable binding to cells in their microenvironment including endothelium and blood constituents through glycan-binding receptors – lectins. In this review, we will discuss current concepts how tumor-cell-derived glycans contribute to metastasis with the focus on three types of lectins: siglecs, galectins, and selectins. Siglecs are present on virtually all hematopoietic cells and usually negatively regulate immune responses. Galectins are mostly expressed by tumor cells and support tumor-cell survival. Selectins are vascular adhesion receptors that promote tumor-cell dissemination. All lectins facilitate interactions within the tumor microenvironment and thereby promote cancer progression. The identification of mechanisms how tumor glycans contribute to metastasis may help to improve diagnosis, prognosis, and aid to develop clinical strategies to prevent metastasis. PMID:24592356

  6. 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

  7. 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.

  8. 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

  9. 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

  10. 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

  11. Recent developments in glycosyl urea synthesis.

    PubMed

    McKay, Matthew J; Nguyen, Hien M

    2014-02-19

    The area of sugar urea derivatives has received considerable attention in recent years because of the unique structural properties and activities that these compounds display. The urea-linkage at the anomeric center is a robust alternative to the naturally occurring O- and N-glycosidic linkages of oligosaccharides and glycoconjugates, and the natural products that have been identified to contain these structures show remarkable biological activity. While methods for installing the β-urea-linkage at the anomeric center have been around for decades, the first synthesis of α-urea glycosides has been much more recent. In either case, the selective synthesis of glycosyl ureas can be quite challenging, and a mixture of α- and β-isomers will often result. This paper will provide a comprehensive review of the synthetic approaches to α- and β-urea glycosides and examine the structure and activity of the natural products and their analogues that have been identified to contain them.

  12. Effects of N-glycosylation of the human cation channel TRPA1 on agonist-sensitivity

    PubMed Central

    Egan, Timothy J.; Acuña, Mario A.; Zenobi-Wong, Marcy; Zeilhofer, Hanns Ulrich; Urech, David

    2016-01-01

    Determining the functional significance of post-translational modifications advances our understanding of many broadly-expressed proteins, and particularly ion channels. The enzymes that catalyse these modifications are often expressed in a cell-type specific manner, resulting in considerable structural diversity among post-translationally modified proteins that are expressed across a variety of cell types. TRP channels exhibit notably variable behaviour between cell types in vitro and in vivo, and they are frequently modified with N-glycans that contribute to protein function. TRPA1 possesses two putative N-linked glycosylation sites at Asn747 and Asn753 that have not yet been studied in detail. In the present study, we show that both of these sites can be modified with an N-glycan and that the glycan at position Asn747 modulates agonist-sensitivity of TRPA1 in vitro. Additionally, we found that N-glycosylation also modulates cooperative effects of temperature and the agonist cinnamaldehyde (CA) on TRPA1 channel activation. Collectively, these findings suggest a dynamic role played by the N-glycosylation of human TRPA1. They also provide further evidence of the versatility of N-glycans and will assist in efforts to fully understand the complex regulation of TRPA1 activity. PMID:27582506

  13. Recent structural and mechanistic insights into protein O-GalNAc glycosylation.

    PubMed

    Hurtado-Guerrero, Ramon

    2016-02-01

    Protein O-GalNAcylation is an abundant post-translational modification and predicted to occur in over 80% of the proteins passing through the Golgi apparatus. This modification is driven by 20 polypeptide GaINAc (N-acetylgalactosamine)-transferases (GalNAc-Ts), which are unique in that they possess both catalytic and lectin domains. The peptide substrate specificities of GalNAc-Ts are still poorly defined and our understanding of the sequence and structural features that direct O-glycosylation of proteins is limited. Part of this may be attributed to the complex regulation by coordinated action of multiple GalNAc-T isoforms, and part of this may also be attributed to the two functional domains of GalNAc-Ts that both seems to be involved in directing the substrate specificities. Recent studies have resulted in 3D structures of GalNAc-Ts and determination of the reaction mechanism of this family of enzymes. Key advances include the trapping of binary/ternary complexes in combination with computational simulations and AFM/small-SAXS experiments, which have allowed for the dissection of the reaction coordinates and the mechanism by which the lectin domains modulate the glycosylation. These studies not only broaden our knowledge of the modes-of-action of this family of enzymes but also open up potential avenues for the rational design of effective and selective inhibitors of O-glycosylation.

  14. 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

  15. 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

  16. 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

  17. 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

  18. 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

  19. 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

  20. 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

  1. 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

  2. The Dismantling of Nuclear Submarines in North-West Russia An Overview of two projects and the end products

    SciTech Connect

    Simmons, V.M.; Wells, D.A.; Field, D.P.; Crimp, C.D.H.

    2006-07-01

    This paper explains the background to the projects, and the setting up of the contracts to dismantle two Oscar-I submarines and one Victor-III submarine. As a pre -cursor to the dismantling, Russian documentation covering environmental, safety, operational and technical issues had to be prepared and submitted to the Russian regulatory bodies for approval, including a full Environmental Impact Assessment (EIA) of the projects. In addition to the dismantling projects, funds were also made available for shipyard infrastructure improvement projects necessary to ensure the safe and efficient completion of the projects. The paper describes these aspects as well as the submarines themselves and gives an overview of the dismantling process. It also describes the nature of the wastes produced, including handling and processing together with the safety and environmental issues. Project Management and monitoring contracted to RWE NUKEM by the U.K. Department of Trade and Industry (DTI) is described emphasizing the importance of strong working relationships between British and Russian teams. Finally the paper discusses the 'end products' of the Oscar-I and Victor-III dismantling and how the projects have provided a useful, high-profile platform on which to demonstrate the success of the DTI and their contractors in helping the U.K. meet its commitments under the Global Partnership Initiative. (authors)

  3. Composting toilets a misnomer: excessive ammonia from urine inhibits microbial activity yet is insufficient in sanitizing the end-product.

    PubMed

    Hill, Geoffrey B; Baldwin, Susan A; Vinnerås, Björn

    2013-04-15

    End-product from 16 public mixed latrine style composting toilets (CTs) at 12 sites between 50 and 2100 m.a.s.l. in Western North America was tested in order to evaluate the effect of composting variables (TS%, NH3-N, temperature, and material age) on compost quality and hygiene (VS%, Escherichia coli, [Formula: see text] -N, and pH). Principal component analysis indicated that TS%, temperature, and material age equally contributed to reduction in VS%. NH3-N had the greatest effect on [Formula: see text] -N, E. coli, and pH. Nitrification was significantly inhibited above 386 mg/kg NH3-N, but no such limit was found for E. coli, despite a significant (p = 0.016) but weak (r(2) = 0.11) negative relationship. It may be possible to amplify the sanitizing effect of ammonia and overcome pathogen resistance due to low temperatures and re-contamination (caused by poor design) with generous dosing of urea and ash. However, even sanitized, the fertilization effect of discharged material on the natural environment may not be desired or permitted in parks or protected areas where many CTs were found. To this end, operators of CTs need to evaluate their primary management objectives and ensure congruency with proven system capabilities. PMID:23435183

  4. 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

  5. Hassallidins, antifungal glycolipopeptides, are widespread among cyanobacteria and are the end-product of a nonribosomal pathway

    PubMed Central

    Vestola, Johanna; Shishido, Tania K.; Jokela, Jouni; Fewer, David P.; Aitio, Olli; Permi, Perttu; Wahlsten, Matti; Wang, Hao; Rouhiainen, Leo; Sivonen, Kaarina

    2014-01-01

    Cyanobacteria produce a wide variety of cyclic peptides, including the widespread hepatotoxins microcystins and nodularins. Another class of peptides, cyclic glycosylated lipopeptides called hassallidins, show antifungal activity. Previously, two hassallidins (A and B) were reported from an epilithic cyanobacterium Hassallia sp. and found to be active against opportunistic human pathogenic fungi. Bioinformatic analysis of the Anabaena sp. 90 genome identified a 59-kb cryptic inactive nonribosomal peptide synthetase gene cluster proposed to be responsible for hassallidin biosynthesis. Here we describe the hassallidin biosynthetic pathway from Anabaena sp. SYKE748A, as well as the large chemical variation and common occurrence of hassallidins in filamentous cyanobacteria. Analysis demonstrated that 20 strains of the genus Anabaena carry hassallidin synthetase genes and produce a multitude of hassallidin variants that exhibit activity against Candida albicans. The compounds discovered here were distinct from previously reported hassallidins A and B. The IC50 of hassallidin D was 0.29–1.0 µM against Candida strains. A large variation in amino acids, sugars, their degree of acetylation, and fatty acid side chain length was detected. In addition, hassallidins were detected in other cyanobacteria including Aphanizomenon, Cylindrospermopsis raciborskii, Nostoc, and Tolypothrix. These compounds may protect some of the most important bloom-forming and globally distributed cyanobacteria against attacks by parasitic fungi. PMID:24742428

  6. 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

  7. Aberrant glycosylation associated with enzymes as cancer biomarkers

    PubMed Central

    2011-01-01

    Background One of the new roles for enzymes in personalized medicine builds on a rational approach to cancer biomarker discovery using enzyme-associated aberrant glycosylation. A hallmark of cancer, aberrant glycosylation is associated with differential expressions of enzymes such as glycosyltransferase and glycosidases. The aberrant expressions of the enzymes in turn cause cancer cells to produce glycoproteins with specific cancer-associated aberrations in glycan structures. Content In this review we provide examples of cancer biomarker discovery using aberrant glycosylation in three areas. First, changes in glycosylation machinery such as glycosyltransferases/glycosidases could be used as cancer biomarkers. Second, most of the clinically useful cancer biomarkers are glycoproteins. Discovery of specific cancer-associated aberrations in glycan structures of these existing biomarkers could improve their cancer specificity, such as the discovery of AFP-L3, fucosylated glycoforms of AFP. Third, cancer-associated aberrations in glycan structures provide a compelling rationale for discovering new biomarkers using glycomic and glycoproteomic technologies. Summary As a hallmark of cancer, aberrant glycosylation allows for the rational design of biomarker discovery efforts. But more important, we need to translate these biomarkers from discovery to clinical diagnostics using good strategies, such as the lessons learned from translating the biomarkers discovered using proteomic technologies to OVA 1, the first FDA-cleared In Vitro Diagnostic Multivariate Index Assay (IVDMIA). These lessons, providing important guidance in current efforts in biomarker discovery and translation, are applicable to the discovery of aberrant glycosylation associated with enzymes as cancer biomarkers as well. PMID:21906357

  8. 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

    2015-12-04

    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.

  9. Disulfide bonds and glycosylation in fungal peroxidases.

    PubMed

    Limongi, P; Kjalke, M; Vind, J; Tams, J W; Johansson, T; Welinder, K G

    1995-01-15

    Four conserved disulfide bonds and N-linked and O-linked glycans of extracellular fungal peroxidases have been identified from studies of a lignin and a manganese peroxidase from Trametes versicolor, and from Coprinus cinereus peroxidase (CIP) and recombinant C. cinereus peroxidase (rCIP) expressed in Aspergillus oryzae. The eight cysteine residues are linked 1-3, 2-7, 4-5 and 6-8, and are located differently from the four conserved disulfide bridges present in the homologous plant peroxidases. CIP and rCIP were identical in their glycosylation pattern, although the extent of glycan chain heterogeneity depended on the fermentation batch. CIP and rCIP have one N-linked glycan composed only of GlcNAc and Man at residue Asn142, and two O-linked glycans near the C-terminus. The major glycoform consists of single Man residues at Thr331 and at Ser338. T. versicolor lignin isoperoxidase TvLP10 contains a single N-linked glycan composed of (GlcNAc)2Man5 bound to Asn103, whereas (GlcNAc)2Man3 was found in T. versicolor manganese isoperoxidase TvMP2 at the same position. In addition, mass spectrometry of the C-terminal peptide of TvMP2 indicated the presence of five Man residues in O-linked glycans. No phosphate was found in these fungal peroxidases.

  10. Site-Selective Glycosylation of Hemoglobin on Cys β93

    PubMed Central

    Zhang, Yalong; Bhatt, Veer S.; Sun, Guoyong; Wang, Peng G.; Palmer, Andre F.

    2009-01-01

    In this work, we describe the synthesis and characterization of a novel glycosylated hemoglobin (Hb) with high oxygen affinity as a potential Hb-based oxygen carrier. Site-selective glycosylation of bovine Hb was achieved by conjugating a lactose derivative to Cys 93 on the β subunit of Hb. LC-MS analysis indicates that the reaction was quantitative, with no unmodified Hb present in the reaction product. The glycosylation site was identified by chymotrypsin digestion of the glycosylated bovine Hb followed with LC-MS/MS and from the X-ray crystal structure of the glycosylated Hb. The chemical conjugation of the lactose derivative at Cys β93 yields an oxygen carrier with a high oxygen affinity (P50 of 4.94 mmHg) and low cooperativity coefficient (n) of 1.20. Asymmetric flow field-flow fractionation (AFFFF) coupled with multi-angle static light scattering (MASLS) was used to measure the absolute molecular weight of the glycosylated Hb. AFFFF-MASLS analysis indicates that glycosylation of Hb significantly altered the α2β2-αβ equilibrium compared to native Hb. Subsequent X-ray analysis of the glycosylated Hb crystal showed that the covalently linked lactose derivative is sandwiched between the β1 and α2 (and hence by symmetry the β2 and α1) subunits of the tetramer, and the interaction between the saccharide and amino acid residues located at the interface is apparently stabilized by hydrogen bonding interactions. The resultant structural analysis of the glycosylated Hb helps to explain the shift in the α2β2-αβ equilibrium in terms of the hydrogen bonding interactions at the β1α2/β2α1 interface. Taken together, all of these results indicate that it is feasible to site-specifically glycosylate Hb. This work has great potential in developing an oxygen carrier with defined chemistry that can target oxygen delivery to low pO2 tissues and organs. PMID:18925771

  11. Identification and characterization of protein glycosylation using specific endo- and exoglycosidases.

    PubMed

    Magnelli, Paula E; Bielik, Alicia M; Guthrie, Ellen P

    2011-01-01

    Glycosylation, the addition of covalently linked sugars, is a major post-translational modification of proteins that can significantly affect processes such as cell adhesion, molecular trafficking, clearance, and signal transduction. In eukaryotes, the most common glycosylation modifications in the secretory pathway are additions at consensus asparagine residues (N-linked); or at serine or threonine residues (O-linked) (Figure 1). Initiation of N-glycan synthesis is highly conserved in eukaryotes, while the end products can vary greatly among different species, tissues, or proteins. Some glycans remain unmodified ("high mannose N-glycans") or are further processed in the Golgi ("complex N-glycans"). Greater diversity is found for O-glycans, which start with a common N-Acetylgalactosamine (GalNAc) residue in animal cells but differ in lower organisms. The detailed analysis of the glycosylation of proteins is a field unto itself and requires extensive resources and expertise to execute properly. However a variety of available enzymes that remove sugars (glycosidases) makes possible to have a general idea of the glycosylation status of a protein in a standard laboratory setting. Here we illustrate the use of glycosidases for the analysis of a model glycoprotein: recombinant human chorionic gonadotropin beta (hCGβ), which carries two N-glycans and four O-glycans. The technique requires only simple instrumentation and typical consumables, and it can be readily adapted to the analysis of multiple glycoprotein samples. Several enzymes can be used in parallel to study a glycoprotein. PNGase F is able to remove almost all types of N-linked glycans. For O-glycans, there is no available enzyme that can cleave an intact oligosaccharide from the protein backbone. Instead, O-glycans are trimmed by exoglycosidases to a short core, which is then easily removed by O-Glycosidase. The Protein Deglycosylation Mix contains PNGase F, O-Glycosidase, Neuraminidase (sialidase), β1

  12. Prion propagation in cells expressing PrP glycosylation mutants.

    PubMed

    Salamat, Muhammad K; Dron, Michel; Chapuis, Jérôme; Langevin, Christelle; Laude, Hubert

    2011-04-01

    Infection by prions involves conversion of a host-encoded cell surface protein (PrP(C)) to a disease-related isoform (PrP(Sc)). PrP(C) carries two glycosylation sites variably occupied by complex N-glycans, which have been suggested by previous studies to influence the susceptibility to these diseases and to determine characteristics of prion strains. We used the Rov cell system, which is susceptible to sheep prions, to generate a series of PrP(C) glycosylation mutants with mutations at one or both attachment sites. We examined their subcellular trafficking and ability to convert into PrP(Sc) and to sustain stable prion propagation in the absence of wild-type PrP. The susceptibility to infection of mutants monoglycosylated at either site differed dramatically depending on the amino acid substitution. Aglycosylated double mutants showed overaccumulation in the Golgi compartment and failed to be infected. Introduction of an ectopic glycosylation site near the N terminus fully restored cell surface expression of PrP but not convertibility into PrP(Sc), while PrP(C) with three glycosylation sites conferred cell permissiveness to infection similarly to the wild type. In contrast, predominantly aglycosylated molecules with nonmutated N-glycosylation sequons, produced in cells expressing glycosylphosphatidylinositol-anchorless PrP(C), were able to form infectious PrP(Sc). Together our findings suggest that glycosylation is important for efficient trafficking of anchored PrP to the cell surface and sustained prion propagation. However, properly trafficked glycosylation mutants were not necessarily prone to conversion, thus making it difficult in such studies to discern whether the amino acid changes or glycan chain removal most influences the permissiveness to prion infection. PMID:21248032

  13. Sucrose synthase: A unique glycosyltransferase for biocatalytic glycosylation process development.

    PubMed

    Schmölzer, Katharina; Gutmann, Alexander; Diricks, Margo; Desmet, Tom; Nidetzky, Bernd

    2016-01-01

    Sucrose synthase (SuSy, EC 2.4.1.13) is a glycosyltransferase (GT) long known from plants and more recently discovered in bacteria. The enzyme catalyzes the reversible transfer of a glucosyl moiety between fructose and a nucleoside diphosphate (NDP) (sucrose+NDP↔NDP-glucose+fructose). The equilibrium for sucrose conversion is pH dependent, and pH values between 5.5 and 7.5 promote NDP-glucose formation. The conversion of a bulk chemical to high-priced NDP-glucose in a one-step reaction provides the key aspect for industrial interest. NDP-sugars are important as such and as key intermediates for glycosylation reactions by highly selective Leloir GTs. SuSy has gained renewed interest as industrially attractive biocatalyst, due to substantial scientific progresses achieved in the last few years. These include biochemical characterization of bacterial SuSys, overproduction of recombinant SuSys, structural information useful for design of tailor-made catalysts, and development of one-pot SuSy-GT cascade reactions for production of several relevant glycosides. These advances could pave the way for the application of Leloir GTs to be used in cost-effective processes. This review provides a framework for application requirements, focusing on catalytic properties, heterologous enzyme production and reaction engineering. The potential of SuSy biocatalysis will be presented based on various biotechnological applications: NDP-sugar synthesis; sucrose analog synthesis; glycoside synthesis by SuSy-GT cascade reactions. PMID:26657050

  14. Glycosylated hemoglobin and hyperbaric oxygen coverage denials.

    PubMed

    Moffat, A D; Worth, E R; Weaver, L K

    2015-01-01

    Some Medicaid and Medicare fiscal intermediaries are denying hyperbaric oxygen (HBO2) therapy for diabetic foot ulcer (DFU) patients if the glycosylated hemoglobin (HbA1c) > 7.0%. We performed multiple PubMed searches for any diabetic wound healing clinical trial that documented HbA1c and had a wound healing endpoint. We scrutinized 30 peer-reviewed clinical trials, representing more than 4,400 patients. The average HbA1c from the intervention side of the studies was 8.6% (7.2% - 9.9%) and the control/sham side was 8.3% (6.0% - 10.6%). Twelve studies made a direct attempt to link HbA1c and wound healing. Four retrospective studies and one prospective cohort study assert that lower HbA1c favors wound healing, but review of the studies reveal design flaws that invalidate these conclusions. In total, 25 studies showed no direct correlation between HbA1c levels and wound healing. There was no randomized controlled trial (RCT) data demonstrating that HbA1c < 7.0% improves diabetic wound healing. In every study reviewed, wounds healed with high HbA1c levels that would be considered poorly controlled by the American Diabetes Association (ADA). Frequently, patients lack optimal blood glucose control when they have a limb-threatening DFU. The evidence supports that denying hyperbaric oxygen to those with HbA1c > 7.0% is unfounded. PMID:26152104

  15. Glycosylated Nanoparticles as Efficient Antimicrobial Delivery Agents.

    PubMed

    Eissa, Ahmed M; Abdulkarim, Ali; Sharples, Gary J; Cameron, Neil R

    2016-08-01

    Synthetic polymer nanoparticles that can be tailored through multivalent ligand display on the surface, while at the same time allowing encapsulation of desired bioactive molecules, are especially useful in providing a versatile and robust platform in the design of specific delivery vehicles for various purposes. Glycosylated nanoparticles (glyco-NPs) of a poly(n-butyl acrylate) (pBA) core and poly(N-2-(β-d-glucosyloxy)ethyl acrylamide) (p(NβGlcEAM)) or poly(N-2-(β-D-galactosyloxy)ethyl acrylamide) (p(NβGalEAM)) corona were prepared via nanoprecipitation in aqueous solutions of preformed amphiphilic glycopolymers. Well-defined block copolymers of (poly(pentafluorophenyl acrylate) (pPFPA) and pBA were first prepared by RAFT polymerization followed by postpolymerization functionalization with aminoethyl glycosides to yield p(NβGlcEAM-b-BA) and p(NβGalEAM-b-BA), which were then used to form glyco-NPs (glucosylated and galactosylated NPs, Glc-NPs and Gal-NPs, respectively). The glyco-NPs were characterized by dynamic light scattering (DLS) and TEM. Encapsulation and release of ampicillin, leading to nanoparticles that we have termed "glyconanobiotics", were studied. The ampicillin-loaded glyco-NPs were found to induce aggregation of Staphylococcus aureus and Escherichia coli and resulted in antibacterial activity approaching that of ampicillin itself. This glyconanobiotics strategy represents a potential new approach for the delivery of antibiotics close to the surface of bacteria by promoting bacterial aggregation. Defined release in the proximity of the bacterial envelope may thus enhance antibacterial efficiency and potentially reduce the quantities of agent required for potency. PMID:27434596

  16. Glycosylated hemoglobin and hyperbaric oxygen coverage denials.

    PubMed

    Moffat, A D; Worth, E R; Weaver, L K

    2015-01-01

    Some Medicaid and Medicare fiscal intermediaries are denying hyperbaric oxygen (HBO2) therapy for diabetic foot ulcer (DFU) patients if the glycosylated hemoglobin (HbA1c) > 7.0%. We performed multiple PubMed searches for any diabetic wound healing clinical trial that documented HbA1c and had a wound healing endpoint. We scrutinized 30 peer-reviewed clinical trials, representing more than 4,400 patients. The average HbA1c from the intervention side of the studies was 8.6% (7.2% - 9.9%) and the control/sham side was 8.3% (6.0% - 10.6%). Twelve studies made a direct attempt to link HbA1c and wound healing. Four retrospective studies and one prospective cohort study assert that lower HbA1c favors wound healing, but review of the studies reveal design flaws that invalidate these conclusions. In total, 25 studies showed no direct correlation between HbA1c levels and wound healing. There was no randomized controlled trial (RCT) data demonstrating that HbA1c < 7.0% improves diabetic wound healing. In every study reviewed, wounds healed with high HbA1c levels that would be considered poorly controlled by the American Diabetes Association (ADA). Frequently, patients lack optimal blood glucose control when they have a limb-threatening DFU. The evidence supports that denying hyperbaric oxygen to those with HbA1c > 7.0% is unfounded.

  17. Activated carbons from end-products of tree nut and tree fruit production as sorbents for removing methyl bromide in ventilation effluent from postharvest chamber fumigation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    End-products of tree nuts and tree fruits grown in California, USA were evaluated for the ability to remove methyl bromide from the ventilation effluent of postharvest chamber fumigations. Activated carbon sorbents from walnut and almond shells as well as peach and prune pits were prepared using dif...

  18. Challenges of glycosylation analysis and control: an integrated approach to producing optimal and consistent therapeutic drugs.

    PubMed

    Zhang, Peiqing; Woen, Susanto; Wang, Tianhua; Liau, Brian; Zhao, Sophie; Chen, Chen; Yang, Yuansheng; Song, Zhiwei; Wormald, Mark R; Yu, Chuanfei; Rudd, Pauline M

    2016-05-01

    Glycosylation of therapeutic proteins has a profound impact on their safety and efficacy. Many factors shape the glycosylation of biotherapeutics, ranging from expression systems and cell culture processes to downstream purification strategies. Various analytical technologies have been developed to address questions concerning different aspects of glycosylation. Informatics tools are also crucial for a systematic understanding of the glycosylation processes. Hence, an integrated approach is required to harness glycosylation for the production of optimal and consistent glycoprotein-based therapeutic drugs. Here, we review the latest developments and challenges in glycosylation analysis and control in the context of bioprocessing monoclonal antibodies.

  19. Small Glycosylated Lignin Oligomers Are Stored in Arabidopsis Leaf Vacuoles

    PubMed Central

    Dima, Oana; Morreel, Kris; Vanholme, Bartel; Kim, Hoon; Ralph, John; Boerjan, Wout

    2015-01-01

    Lignin is an aromatic polymer derived from the combinatorial coupling of monolignol radicals in the cell wall. Recently, various glycosylated lignin oligomers have been revealed in Arabidopsis thaliana. Given that monolignol oxidation and monolignol radical coupling are known to occur in the apoplast, and glycosylation in the cytoplasm, it raises questions about the subcellular localization of glycosylated lignin oligomer biosynthesis and their storage. By metabolite profiling of Arabidopsis leaf vacuoles, we show that the leaf vacuole stores a large number of these small glycosylated lignin oligomers. Their structural variety and the incorporation of alternative monomers, as observed in Arabidopsis mutants with altered monolignol biosynthesis, indicate that they are all formed by combinatorial radical coupling. In contrast to the common believe that combinatorial coupling is restricted to the apoplast, we hypothesized that the aglycones of these compounds are made within the cell. To investigate this, leaf protoplast cultures were cofed with 13C6-labeled coniferyl alcohol and a 13C4-labeled dimer of coniferyl alcohol. Metabolite profiling of the cofed protoplasts provided strong support for the occurrence of intracellular monolignol coupling. We therefore propose a metabolic pathway involving intracellular combinatorial coupling of monolignol radicals, followed by oligomer glycosylation and vacuolar import, which shares characteristics with both lignin and lignan biosynthesis. PMID:25700483

  20. Impact of glycosylation on the unimpaired functions of the sperm

    PubMed Central

    2015-01-01

    One of the key factors of early development is the specification of competence between the oocyte and the sperm, which occurs during gametogenesis. However, the starting point, growth, and maturation for acquiring competence during spermatogenesis and oogenesis in mammals are very different. Spermatogenesis includes spermiogenesis, but such a metamorphosis is not observed during oogenesis. Glycosylation, a ubiquitous modification, is a preliminary requisite for distribution of the structural and functional components of spermatids for metamorphosis. In addition, glycosylation using epididymal or female genital secretory glycans is an important process for the sperm maturation, the acquisition of the potential for fertilization, and the acceleration of early embryo development. However, nonemzymatic unexpected covalent bonding of a carbohydrate and malglycosylation can result in falling fertility rates as shown in the diabetic male. So far, glycosylation during spermatogenesis and the dynamics of the plasma membrane in the process of capacitation and fertilization have been evaluated, and a powerful role of glycosylation in spermatogenesis and early development is also suggested by structural bioinformatics, functional genomics, and functional proteomics. Further understanding of glycosylation is needed to provide a better understanding of fertilization and embryo development and for the development of new diagnostic and therapeutic tools for infertility. PMID:26473106

  1. Glycosylation: impact, control and improvement during therapeutic protein production.

    PubMed

    Costa, Ana Rita; Rodrigues, Maria Elisa; Henriques, Mariana; Oliveira, Rosário; Azeredo, Joana

    2014-12-01

    The emergence of the biopharmaceutical industry represented a major revolution for modern medicine, through the development of recombinant therapeutic proteins that brought new hope for many patients with previously untreatable diseases. There is a ever-growing demand for these therapeutics that forces a constant technological evolution to increase product yields while simultaneously reducing costs. However, the process changes made for this purpose may also affect the quality of the product, a factor that was initially overlooked but which is now a major focus of concern. Of the many properties determining product quality, glycosylation is regarded as one of the most important, influencing, for example, the biological activity, serum half-life and immunogenicity of the protein. Consequently, monitoring and control of glycosylation is now critical in biopharmaceutical manufacturing and a requirement of regulatory agencies. A rapid evolution is being observed in this context, concerning the influence of glycosylation in the efficacy of different therapeutic proteins, the impact on glycosylation of a diversity of parameters/processes involved in therapeutic protein production, the analytical methodologies employed for glycosylation monitoring and control, as well as strategies that are being explored to use this property to improve therapeutic protein efficacy (glycoengineering). This work reviews the main findings on these subjects, providing an up-to-date source of information to support further studies.

  2. Site-specific protein glycosylation analysis with glycan isomer differentiation.

    PubMed

    Hua, Serenus; Nwosu, Charles C; Strum, John S; Seipert, Richard R; An, Hyun Joo; Zivkovic, Angela M; German, J Bruce; Lebrilla, Carlito B

    2012-05-01

    Glycosylation is one of the most common yet diverse post-translational modifications. Information on glycan heterogeneity and glycosite occupancy is increasingly recognized as crucial to understanding glycoprotein structure and function. Yet, no approach currently exists with which to holistically consider both the proteomic and glycomic aspects of a system. Here, we developed a novel method of comprehensive glycosite profiling using nanoflow liquid chromatography/mass spectrometry (nano-LC/MS) that shows glycan isomer-specific differentiation on specific sites. Glycoproteins were digested by controlled non-specific proteolysis in order to produce informative glycopeptides. High-resolution, isomer-sensitive chromatographic separation of the glycopeptides was achieved using microfluidic chip-based capillaries packed with graphitized carbon. Integrated LC/MS/MS not only confirmed glycopeptide composition but also differentiated glycan and peptide isomers and yielded structural information on both the glycan and peptide moieties. Our analysis identified at least 13 distinct glycans (including isomers) corresponding to five compositions at the single N-glycosylation site on bovine ribonuclease B, 59 distinct glycans at five N-glycosylation sites on bovine lactoferrin, 13 distinct glycans at one N-glycosylation site on four subclasses of human immunoglobulin G, and 20 distinct glycans at five O-glycosylation sites on bovine κ-casein. Porous graphitized carbon provided effective separation of glycopeptide isomers. The integration of nano-LC with MS and MS/MS of non-specifically cleaved glycopeptides allows quantitative, isomer-sensitive, and site-specific glycoprotein analysis.

  3. Studying N-linked glycosylation of receptor tyrosine kinases.

    PubMed

    Itkonen, Harri M; Mills, Ian G

    2015-01-01

    Metabolic alterations have been identified as a frequent event in cancer. This is often associated with increased flux through glycolysis, and also a secondary pathway to glycolysis, hexosamine biosynthetic pathway (HBP). HBP provides substrate for N-linked glycosylation, which occurs in the endoplasmic reticulum and the Golgi apparatus. N-linked glycosylation supports protein folding and correct sorting of proteins to plasma membrane and secretion. This process generates complex glycoforms, which can be recognized by other proteins and glycosylation of receptor tyrosine kinases (RTK) can also regulate their plasma-membrane retention time. Of special interest for experimental biologists, plants produce proteins, termed lectins, which bind with high specificity to glyco-conjugates. For the purposes of molecular biology, plant lectins can be conjugated to different moieties, such as agarose beads, which enable precipitation of specifically glycosylated proteins. In this chapter, we describe in detail how to perform pull-down experiments with commercially available lectins to identify changes in the glycosylation of RTKs. PMID:25319893

  4. Mucin-Type O-Glycosylation in Gastric Carcinogenesis.

    PubMed

    Duarte, Henrique O; Freitas, Daniela; Gomes, Catarina; Gomes, Joana; Magalhães, Ana; Reis, Celso A

    2016-01-01

    Mucin-type O-glycosylation plays a crucial role in several physiological and pathological processes of the gastric tissue. Modifications in enzymes responsible for key glycosylation steps and the consequent abnormal biosynthesis and expression of their glycan products constitute well-established molecular hallmarks of disease state. This review addresses the major role played by mucins and associated O-glycan structures in Helicobacter pylori adhesion to the gastric mucosa and the subsequent establishment of a chronic infection, with concomitant drastic alterations of the gastric epithelium glycophenotype. Furthermore, alterations of mucin expression pattern and glycan signatures occurring in preneoplastic lesions and in gastric carcinoma are also described, as well as their impact throughout the gastric carcinogenesis cascade and in cancer progression. Altogether, mucin-type O-glycosylation alterations may represent promising biomarkers with potential screening and prognostic applications, as well as predictors of cancer patients' response to therapy. PMID:27409642

  5. Mucin-Type O-Glycosylation in Gastric Carcinogenesis

    PubMed Central

    Duarte, Henrique O.; Freitas, Daniela; Gomes, Catarina; Gomes, Joana; Magalhães, Ana; Reis, Celso A.

    2016-01-01

    Mucin-type O-glycosylation plays a crucial role in several physiological and pathological processes of the gastric tissue. Modifications in enzymes responsible for key glycosylation steps and the consequent abnormal biosynthesis and expression of their glycan products constitute well-established molecular hallmarks of disease state. This review addresses the major role played by mucins and associated O-glycan structures in Helicobacter pylori adhesion to the gastric mucosa and the subsequent establishment of a chronic infection, with concomitant drastic alterations of the gastric epithelium glycophenotype. Furthermore, alterations of mucin expression pattern and glycan signatures occurring in preneoplastic lesions and in gastric carcinoma are also described, as well as their impact throughout the gastric carcinogenesis cascade and in cancer progression. Altogether, mucin-type O-glycosylation alterations may represent promising biomarkers with potential screening and prognostic applications, as well as predictors of cancer patients’ response to therapy. PMID:27409642

  6. Taming the Reactivity of Glycosyl Iodides To Achieve Stereoselective Glycosidation.

    PubMed

    Gervay-Hague, Jacquelyn

    2016-01-19

    Although glycosyl iodides have been known for more than 100 years, it was not until the 21st century that their full potential began to be harnessed for complex glycoconjugate synthesis. Mechanistic studies in the late 1990s probed glycosyl iodide formation by NMR spectroscopy and revealed important reactivity features embedded in protecting-group stereoelectronics. Differentially protected sugars having an anomeric acetate were reacted with trimethylsilyl iodide (TMSI) to generate the glycosyl iodides. In the absence of C-2 participation, generation of the glycosyl iodide proceeded by inversion of the starting anomeric acetate stereochemistry. Once formed, the glycosyl iodide readily underwent in situ anomerization, and in the presence of excess iodide, equilibrium concentrations of α- and β-iodides were established. Reactivity profiles depended upon the identity of the sugar and the protecting groups adorning it. Consistent with the modern idea of disarmed versus armed sugars, ester protecting groups diminished the reactivity of glycosyl iodides and ether protecting groups enhanced the reactivity. Thus, acetylated sugars were slower to form the iodide and anomerize than their benzylated analogues, and these disarmed glycosyl iodides could be isolated and purified, whereas armed ether-protected iodides could only be generated and reacted in situ. All other things being equal, the β-iodide was orders of magnitude more reactive than the thermodynamically more stable α-iodide, consistent with the idea of in situ anomerization introduced by Lemieux in the mid-20th century. Glycosyl iodides are far more reactive than the corresponding bromides, and with the increased reactivity comes increased stereocontrol, particularly when forming α-linked linear and branched oligosaccharides. Reactions with per-O-silylated glycosyl iodides are especially useful for the synthesis of α-linked glycoconjugates. Silyl ether protecting groups make the glycosyl iodide so reactive

  7. Taming the Reactivity of Glycosyl Iodides To Achieve Stereoselective Glycosidation.

    PubMed

    Gervay-Hague, Jacquelyn

    2016-01-19

    Although glycosyl iodides have been known for more than 100 years, it was not until the 21st century that their full potential began to be harnessed for complex glycoconjugate synthesis. Mechanistic studies in the late 1990s probed glycosyl iodide formation by NMR spectroscopy and revealed important reactivity features embedded in protecting-group stereoelectronics. Differentially protected sugars having an anomeric acetate were reacted with trimethylsilyl iodide (TMSI) to generate the glycosyl iodides. In the absence of C-2 participation, generation of the glycosyl iodide proceeded by inversion of the starting anomeric acetate stereochemistry. Once formed, the glycosyl iodide readily underwent in situ anomerization, and in the presence of excess iodide, equilibrium concentrations of α- and β-iodides were established. Reactivity profiles depended upon the identity of the sugar and the protecting groups adorning it. Consistent with the modern idea of disarmed versus armed sugars, ester protecting groups diminished the reactivity of glycosyl iodides and ether protecting groups enhanced the reactivity. Thus, acetylated sugars were slower to form the iodide and anomerize than their benzylated analogues, and these disarmed glycosyl iodides could be isolated and purified, whereas armed ether-protected iodides could only be generated and reacted in situ. All other things being equal, the β-iodide was orders of magnitude more reactive than the thermodynamically more stable α-iodide, consistent with the idea of in situ anomerization introduced by Lemieux in the mid-20th century. Glycosyl iodides are far more reactive than the corresponding bromides, and with the increased reactivity comes increased stereocontrol, particularly when forming α-linked linear and branched oligosaccharides. Reactions with per-O-silylated glycosyl iodides are especially useful for the synthesis of α-linked glycoconjugates. Silyl ether protecting groups make the glycosyl iodide so reactive

  8. Borinic Acid Catalyzed Stereo- and Regioselective Couplings of Glycosyl Methanesulfonates.

    PubMed

    D'Angelo, Kyan A; Taylor, Mark S

    2016-08-31

    In the presence of a diarylborinic acid catalyst, glycosyl methanesulfonates engage in regio- and stereoselective couplings with partially protected pyranoside and furanoside acceptors. The methanesulfonate donors are prepared in situ from glycosyl hemiacetals, and are coupled under mild, operationally simple conditions (amine base, organoboron catalyst, room temperature). The borinic acid catalyst not only influences site-selectivity via activation of 1,2- or 1,3-diol motifs, but also has a pronounced effect on the stereochemical outcome: 1,2-trans-linked disaccharides are obtained selectively in the absence of neighboring group participation. Reaction progress kinetic analysis was used to obtain insight into the mechanism of glycosylation, both in the presence of catalyst and in its absence, while rates of interconversion of methanesulfonate anomers were determined by NMR exchange spectroscopy (EXSY). Together, the results suggest that although the uncatalyzed and catalyzed reactions give rise to opposite stereochemical outcomes, both proceed by associative mechanisms. PMID:27533523

  9. Polar Glycosylated and Lateral Non-Glycosylated Flagella from Aeromonas hydrophila Strain AH-1 (Serotype O11)

    PubMed Central

    Fulton, Kelly M.; Mendoza-Barberá, Elena; Twine, Susan M.; Tomás, Juan M.; Merino, Susana

    2015-01-01

    Polar and but not lateral flagellin proteins from Aeromonas hydrophila strain AH-1 (serotype O11) were found to be glycosylated. Top-down mass spectrometry studies of purified polar flagellins suggested the presence of a 403 Da glycan of mass. Bottom-up mass spectrometry studies showed the polar flagellin peptides to be modified with 403 Da glycans in O-linkage. The MS fragmentation pattern of this putative glycan was similar to that of pseudaminic acid derivative. Mutants lacking the biosynthesis of pseudaminic acid (pseB and pseI homologues) were unable to produce polar flagella but no changes were observed in lateral flagella by post-transcriptional regulation of the flagellin. Complementation was achieved by reintroduction of the wild-type pseB and pseI. We compared two pathogenic features (adhesion to eukaryotic cells and biofilm production) between the wild-type strain and two kinds of mutants: mutants lacking polar flagella glycosylation and lacking the O11-antigen lipopolysaccharide (LPS) but with unaltered polar flagella glycosylation. Results suggest that polar flagella glycosylation is extremely important for A. hydrophila AH-1 adhesion to Hep-2 cells and biofilm formation. In addition, we show the importance of the polar flagella glycosylation for immune stimulation of IL-8 production via toll-“like” receptor 5 (TLR5). PMID:26633358

  10. Polar Glycosylated and Lateral Non-Glycosylated Flagella from Aeromonas hydrophila Strain AH-1 (Serotype O11).

    PubMed

    Fulton, Kelly M; Mendoza-Barberá, Elena; Twine, Susan M; Tomás, Juan M; Merino, Susana

    2015-01-01

    Polar and but not lateral flagellin proteins from Aeromonas hydrophila strain AH-1 (serotype O11) were found to be glycosylated. Top-down mass spectrometry studies of purified polar flagellins suggested the presence of a 403 Da glycan of mass. Bottom-up mass spectrometry studies showed the polar flagellin peptides to be modified with 403 Da glycans in O-linkage. The MS fragmentation pattern of this putative glycan was similar to that of pseudaminic acid derivative. Mutants lacking the biosynthesis of pseudaminic acid (pseB and pseI homologues) were unable to produce polar flagella but no changes were observed in lateral flagella by post-transcriptional regulation of the flagellin. Complementation was achieved by reintroduction of the wild-type pseB and pseI. We compared two pathogenic features (adhesion to eukaryotic cells and biofilm production) between the wild-type strain and two kinds of mutants: mutants lacking polar flagella glycosylation and lacking the O11-antigen lipopolysaccharide (LPS) but with unaltered polar flagella glycosylation. Results suggest that polar flagella glycosylation is extremely important for A. hydrophila AH-1 adhesion to Hep-2 cells and biofilm formation. In addition, we show the importance of the polar flagella glycosylation for immune stimulation of IL-8 production via toll-"like" receptor 5 (TLR5). PMID:26633358

  11. Polar Glycosylated and Lateral Non-Glycosylated Flagella from Aeromonas hydrophila Strain AH-1 (Serotype O11).

    PubMed

    Fulton, Kelly M; Mendoza-Barberá, Elena; Twine, Susan M; Tomás, Juan M; Merino, Susana

    2015-01-01

    Polar and but not lateral flagellin proteins from Aeromonas hydrophila strain AH-1 (serotype O11) were found to be glycosylated. Top-down mass spectrometry studies of purified polar flagellins suggested the presence of a 403 Da glycan of mass. Bottom-up mass spectrometry studies showed the polar flagellin peptides to be modified with 403 Da glycans in O-linkage. The MS fragmentation pattern of this putative glycan was similar to that of pseudaminic acid derivative. Mutants lacking the biosynthesis of pseudaminic acid (pseB and pseI homologues) were unable to produce polar flagella but no changes were observed in lateral flagella by post-transcriptional regulation of the flagellin. Complementation was achieved by reintroduction of the wild-type pseB and pseI. We compared two pathogenic features (adhesion to eukaryotic cells and biofilm production) between the wild-type strain and two kinds of mutants: mutants lacking polar flagella glycosylation and lacking the O11-antigen lipopolysaccharide (LPS) but with unaltered polar flagella glycosylation. Results suggest that polar flagella glycosylation is extremely important for A. hydrophila AH-1 adhesion to Hep-2 cells and biofilm formation. In addition, we show the importance of the polar flagella glycosylation for immune stimulation of IL-8 production via toll-"like" receptor 5 (TLR5).

  12. The Structural Biology of Enzymes Involved in Natural Product Glycosylation

    PubMed Central

    Singh, Shanteri; Phillips, George N.

    2012-01-01

    The glycosylation of microbial natural products often dramatically influences the biological and/or pharmacological activities of the parental metabolite. Over the past decade, crystal structures of several enzymes involved in the biosynthesis and attachment of novel sugars found appended to natural products have emerged. In many cases, these studies have paved the way to a better understanding of the corresponding enzyme mechanism of action and have served as a starting point for engineering variant enzymes to facilitate to production of differentially-glycosylated natural products. This review specifically summarizes the structural studies of bacterial enzymes involved in biosynthesis of novel sugar nucleotides. PMID:22688446

  13. Identification of the N-linked glycosylation sites of vitamin K-dependent carboxylase and the effect of glycosylation on carboxylase function†

    PubMed Central

    Tie, Jian-Ke; Zheng, Mei-Yan; Pope, R. Marshall; Straight, David L.; Stafford, Darrel W.

    2014-01-01

    The vitamin K-dependent carboxylase is an integral membrane protein which is required for the post-translational modification of a variety of vitamin K-dependent proteins. Previous studies have suggested carboxylase is a glycoprotein with N-linked glycosylation sites. In the present study, we identified the N-glycosylation sites of carboxylase by mass spectrometric peptide mapping analyses combined with site-directed mutagenesis. Our mass spectrometric results show that the N-linked glycosylation in carboxylase occurs at positions N459, N550, N605, and N627. Eliminating these glycosylation sites by changing asparagine to glutamine caused the mutant carboxylase to migrate faster in SDS-PAGE gel analyses, adding further evidence that these sites are glycosylated. In addition, the mutation studies identified N525, a site not recoverable by mass spectroscopy analysis, as a glycosylation site. Furthermore, the potential glycosylation site at N570 is glycosylated only if all the five natural glycosylation sites are simultaneously mutated. Removal of the oligosaccharides by glycosidase from wild-type carboxylase or by eliminating the functional glycosylation sites by site-directed mutagenesis did not affect either the carboxylation or epoxidation activity when the small pentapeptide FLEEL was used as substrate, suggesting that N-linked glycosylation is not required for the enzymatic function of carboxylase. In contrast, when site N570 and the five natural glycosylation sites were mutated simultaneously, the resulting carboxylase protein was degraded. Our results suggest that N-linked glycosylation is not essential for carboxylase enzymatic activity but it is important for protein folding and stability. PMID:17144668

  14. Distinct CCR7 glycosylation pattern shapes receptor signaling and endocytosis to modulate chemotactic responses.

    PubMed

    Hauser, Mark A; Kindinger, Ilona; Laufer, Julia M; Späte, Anne-Katrin; Bucher, Delia; Vanes, Sarah L; Krueger, Wolfgang A; Wittmann, Valentin; Legler, Daniel F

    2016-06-01

    The homeostatic chemokines CCL19 and CCL21 and their common cognate chemokine receptor CCR7 orchestrate immune cell trafficking by eliciting distinct signaling pathways. Here, we demonstrate that human CCR7 is N-glycosylated on 2 specific residues in the N terminus and the third extracellular loop. Conceptually, CCR7 glycosylation adds steric hindrance to the receptor N terminus and extracellular loop 3, acting as a "swinging door" to regulate receptor sensitivity and cell migration. We found that freshly isolated human B cells, as well as expanded T cells, but not naïve T cells, express highly sialylated CCR7. Moreover, we identified that human dendritic cells imprint T cell migration toward CCR7 ligands by secreting enzymes that deglycosylate CCR7, thereby boosting CCR7 signaling on T cells, permitting enhanced T cell locomotion, while simultaneously decreasing receptor endocytosis. In addition, dendritic cells proteolytically convert immobilized CCL21 to a soluble form that is more potent in triggering chemotactic movement and does not desensitize the receptor. Furthermore, we demonstrate that soluble CCL21 functionally resembles neither the CCL19 nor the CCL21 phenotype but acts as a chemokine with unique features. Thus, we advance the concept of dendritic cell-dependent generation of micromilieus and lymph node conditioning by demonstrating a novel layer of CCR7 regulation through CCR7 sialylation. In summary, we demonstrate that leukocyte subsets express distinct patterns of CCR7 sialylation that contribute to receptor signaling and fine-tuning chemotactic responses. PMID:26819318

  15. Advanced glycation end products, physico-chemical and sensory characteristics of cooked lamb loins affected by cooking method and addition of flavour precursors.

    PubMed

    Roldan, Mar; Loebner, Jürgen; Degen, Julia; Henle, Thomas; Antequera, Teresa; Ruiz-Carrascal, Jorge

    2015-02-01

    The influence of the addition of a flavour enhancer solution (FES) (d-glucose, d-ribose, l-cysteine and thiamin) and of sous-vide cooking or roasting on moisture, cooking loss, instrumental colour, sensory characteristics and formation of Maillard reaction (MR) compounds in lamb loins was studied. FES reduced cooking loss and increased water content in sous-vide samples. FES and cooking method showed a marked effect on browning development, both on the meat surface and within. FES led to tougher and chewier texture in sous-vide cooked lamb, and enhanced flavour scores of sous-vide samples more markedly than in roasted ones. FES added meat showed higher contents of furosine; 1,2-dicarbonyl compounds and 5-hydroxymethylfurfural did not reach detectable levels. N-ε-carboxymethyllysine amounts were rather low and not influenced by the studied factors. Cooked meat seems to be a minor dietary source of MR products, regardless the presence of reducing sugars and the cooking method. PMID:25172739

  16. Expression of advanced glycation end-products on sun-exposed and non-exposed cutaneous sites during the ageing process in humans.

    PubMed

    Crisan, Maria; Taulescu, Marian; Crisan, Diana; Cosgarea, Rodica; Parvu, Alina; Cãtoi, Cornel; Drugan, Tudor

    2013-01-01

    The glycation process is involved in both the intrinsic (individual, genetic) and extrinsic (ultraviolet light, polution and lifestyle) aging processes, and can be quantified at the epidermal or dermal level by histological, immunohistochemical (IHC), or imagistic methods. Our study is focused on a histological and immunohistological comparison of sun-protected regions versus sun-exposed regions from different age groups of skin phototype III subjects, related to the aging process. Skin samples collected from non-protected and UV protected regions of four experimental groups with different ages, were studied using histology and IHC methods for AGE-CML [N(epsilon)-(carboxymethyl)lysine]. A semi-quantitative assessment of the CML expression in the microvascular endothelium and dermal fibroblasts was performed. The Pearson one-way ANOVA was used to compare data between the groups. In the dermis of sun-exposed skin, the number and the intensity of CML positive cells in both fibroblasts and endothelial cells (p<0.05) was higher compared to sun-protected skin, and was significantly increased in older patients. The sun-exposed areas had a more than 10% higher AGE-CML score than the protected areas. No statistically significant correlation was observed between the histological score and the IHC expression of CML. We concluded that in healthy integument, the accumulation of final glycation products increases with age and is amplified by ultraviolet exposure. The study provides new knowledge on differences of AGE-CML between age groups and protected and unprotected areas and emphasizes that endothelium and perivascular area are most affected, justifying combined topical and systemic therapies.

  17. Expression of Advanced Glycation End-Products on Sun-Exposed and Non-Exposed Cutaneous Sites during the Ageing Process in Humans

    PubMed Central

    Crisan, Maria; Taulescu, Marian; Crisan, Diana; Cosgarea, Rodica; Parvu, Alina; Cãtoi, Cornel; Drugan, Tudor

    2013-01-01

    The glycation process is involved in both the intrinsic (individual, genetic) and extrinsic (ultraviolet light, polution and lifestyle) aging processes, and can be quantified at the epidermal or dermal level by histological, immunohistochemical (IHC), or imagistic methods. Our study is focused on a histological and immunohistological comparison of sun-protected regions versus sun-exposed regions from different age groups of skin phototype III subjects, related to the aging process. Skin samples collected from non-protected and UV protected regions of four experimental groups with different ages, were studied using histology and IHC methods for AGE-CML [N(epsilon)-(carboxymethyl)lysine]. A semi-quantitative assessment of the CML expression in the microvascular endothelium and dermal fibroblasts was performed. The Pearson one-way ANOVA was used to compare data between the groups. In the dermis of sun-exposed skin, the number and the intensity of CML positive cells in both fibroblasts and endothelial cells (p<0.05) was higher compared to sun-protected skin, and was significantly increased in older patients. The sun-exposed areas had a more than 10% higher AGE-CML score than the protected areas. No statistically significant correlation was observed between the histological score and the IHC expression of CML. We concluded that in healthy integument, the accumulation of final glycation products increases with age and is amplified by ultraviolet exposure. The study provides new knowledge on differences of AGE-CML between age groups and protected and unprotected areas and emphasizes that endothelium and perivascular area are most affected, justifying combined topical and systemic therapies. PMID:24116020

  18. Advanced glycation end products, physico-chemical and sensory characteristics of cooked lamb loins affected by cooking method and addition of flavour precursors.

    PubMed

    Roldan, Mar; Loebner, Jürgen; Degen, Julia; Henle, Thomas; Antequera, Teresa; Ruiz-Carrascal, Jorge

    2015-02-01

    The influence of the addition of a flavour enhancer solution (FES) (d-glucose, d-ribose, l-cysteine and thiamin) and of sous-vide cooking or roasting on moisture, cooking loss, instrumental colour, sensory characteristics and formation of Maillard reaction (MR) compounds in lamb loins was studied. FES reduced cooking loss and increased water content in sous-vide samples. FES and cooking method showed a marked effect on browning development, both on the meat surface and within. FES led to tougher and chewier texture in sous-vide cooked lamb, and enhanced flavour scores of sous-vide samples more markedly than in roasted ones. FES added meat showed higher contents of furosine; 1,2-dicarbonyl compounds and 5-hydroxymethylfurfural did not reach detectable levels. N-ε-carboxymethyllysine amounts were rather low and not influenced by the studied factors. Cooked meat seems to be a minor dietary source of MR products, regardless the presence of reducing sugars and the cooking method.

  19. HMGB1 binds to activated platelets via the receptor for advanced glycation end products and is present in platelet rich human coronary artery thrombi.

    PubMed

    Ahrens, Ingo; Chen, Yung-Chih; Topcic, Danijal; Bode, Michael; Haenel, David; Hagemeyer, Christoph E; Seeba, Hannah; Duerschmied, Daniel; Bassler, Nicole; Jandeleit-Dahm, Karin A; Sweet, Matthew J; Agrotis, Alex; Bobik, Alex; Peter, Karlheinz

    2015-11-01

    High mobility group box 1 (HMGB1) acts as both a nuclear protein that regulates gene expression, as well as a pro-inflammatory alarmin that is released from necrotic or activated cells. Recently, HMGB1-expression in human atherosclerotic plaques was identified. Therapeutic blockade of HMGB1 reduced the development of diet-induced atherosclerosis in ApoE knockout mice. Thus, we hypothesised an interaction between HMGB1 and activated platelets. Binding of recombinant HMGB1 to platelets was assessed by flow cytometry. HMGB1 bound to thrombin-activated human platelets (MFI 2.49 vs 25.01, p=0.0079). Blood from wild-type, TLR4 and RAGE knockout mice was used to determine potential HMGB1 receptors on platelets. HMGB1 bound to platelets from wild type C57Bl6 (MFI 2.64 vs 20.3, p< 0.05), and TLR4-/- mice (MFI 2.11 vs 25.65, p< 0.05) but failed to show binding to platelets from RAGE-/- mice (p > 0.05). RAGE expression on human platelets was detected by RT-PCR with mRNA extracted from highly purified platelets and confirmed by Western blot and immunofluorescence microscopy. Platelet activation increased RAGE surface expression (MFI 4.85 vs 6.74, p< 0.05). Expression of HMGB1 in human coronary artery thrombi was demonstrated by immunohistochemistry and revealed high expression levels. Platelets bind HMGB1 upon thrombin-induced activation. Platelet specific expression of RAGE could be detected at the mRNA and protein level and is involved in the binding of HMGB1. Furthermore, platelet activation up-regulates platelet surface expression of RAGE. HMGB1 is highly expressed in platelet-rich human coronary artery thrombi pointing towards a central role for HMGB1 in atherothrombosis, thereby suggesting the possibility of platelet targeted anti-inflammatory therapies for atherothrombosis.

  20. Stabilization of exosome-targeting peptides via engineered glycosylation.

    PubMed

    Hung, Michelle E; Leonard, Joshua N

    2015-03-27

    Exosomes are secreted extracellular vesicles that mediate intercellular transfer of cellular contents and are attractive vehicles for therapeutic delivery of bimolecular cargo such as nucleic acids, proteins, and even drugs. Efficient exosome-mediated delivery in vivo requires targeting vesicles for uptake by specific recipient cells. Although exosomes have been successfully targeted to several cellular receptors by displaying peptides on the surface of the exosomes, identifying effective exosome-targeting peptides for other receptors has proven challenging. Furthermore, the biophysical rules governing targeting peptide success remain poorly understood. To evaluate one factor potentially limiting exosome delivery, we investigated whether peptides displayed on the exosome surface are degraded during exosome biogenesis, for example by endosomal proteases. Indeed, peptides fused to the N terminus of exosome-associated transmembrane protein Lamp2b were cleaved in samples derived from both cells and exosomes. To suppress peptide loss, we engineered targeting peptide-Lamp2b fusion proteins to include a glycosylation motif at various positions. Introduction of this glycosylation motif both protected the peptide from degradation and led to an increase in overall Lamp2b fusion protein expression in both cells and exosomes. Moreover, glycosylation-stabilized peptides enhanced targeted delivery of exosomes to neuroblastoma cells, demonstrating that such glycosylation does not ablate peptide-target interactions. Thus, we have identified a strategy for achieving robust display of targeting peptides on the surface of exosomes, which should facilitate the evaluation and development of new exosome-based therapeutics.

  1. Genetics Home Reference: ALG6-congenital disorder of glycosylation

    MedlinePlus

    ... so they can perform a wider variety of functions. The enzyme produced from the ALG6 gene transfers a simple ... reduced or no activity. Without a properly functioning enzyme, glycosylation ... are needed for normal function in many organs and tissues, including the brain, ...

  2. A glycogene mutation map for discovery of diseases of glycosylation

    PubMed Central

    Hansen, Lars; Lind-Thomsen, Allan; Joshi, Hiren J; Pedersen, Nis Borbye; Have, Christian Theil; Kong, Yun; Wang, Shengjun; Sparso, Thomas; Grarup, Niels; Vester-Christensen, Malene Bech; Schjoldager, Katrine; Freeze, Hudson H; Hansen, Torben; Pedersen, Oluf; Henrissat, Bernard; Mandel, Ulla; Clausen, Henrik; Wandall, Hans H; Bennett, Eric P

    2015-01-01

    Glycosylation of proteins and lipids involves over 200 known glycosyltransferases (GTs), and deleterious defects in many of the genes encoding these enzymes cause disorders collectively classified as congenital disorders of glycosylation (CDGs). Most known CDGs are caused by defects in glycogenes that affect glycosylation globally. Many GTs are members of homologous isoenzyme families and deficiencies in individual isoenzymes may not affect glycosylation globally. In line with this, there appears to be an underrepresentation of disease-causing glycogenes among these larger isoenzyme homologous families. However, genome-wide association studies have identified such isoenzyme genes as candidates for different diseases, but validation is not straightforward without biomarkers. Large-scale whole-exome sequencing (WES) provides access to mutations in, for example, GT genes in populations, which can be used to predict and/or analyze functional deleterious mutations. Here, we constructed a draft of a functional mutational map of glycogenes, GlyMAP, from WES of a rather homogenous population of 2000 Danes. We cataloged all missense mutations and used prediction algorithms, manual inspection and in case of carbohydrate-active enzymes family GT27 experimental analysis of mutations to map deleterious mutations. GlyMAP (http://glymap.glycomics.ku.dk) provides a first global view of the genetic stability of the glycogenome and should serve as a tool for discovery of novel CDGs. PMID:25267602

  3. Congenital disorders of glycosylation with emphasis on cerebellar involvement.

    PubMed

    Barone, Rita; Fiumara, Agata; Jaeken, Jaak

    2014-07-01

    Congenital disorders of glycosylation (CDG) are genetic diseases due to defective glycosylation of proteins and lipids. The authors present an update on these disorders affecting the central nervous system with a focus on cerebellar involvement. The rate of identification of novel CDG shows an exponential increase. Some 76 CDG are actually known, not taking into account the defects in glycan-modifying proteins. Neurologic involvement is present in the large majority of CDG. Screening methods are limited to serum transferrin isoelectrofocusing (for N-glycosylation disorders with sialic acid deficiency), and serum apolipoprotein C-III isoelectrofocusing (for core 1 mucin-type O-glycosylation disorders). Whole exome/genome sequencing is increasingly used in the diagnostic workup of patients with CDG-X. Treatment is greatly lagging behind because only one CDG is efficiently treatable (MPI-CDG). Cerebellar involvement is an important feature of PMM2-CDG, the congenital muscular dystrophies due to dystroglycanopathy, and SRD5A3-CDG. It has also been reported in some patients with ALG1-CDG, ALG3-CDG, ALG9-CDG, ALG6-CDG, ALG8-CDG, PIGA-CDG, DPM1-CDG, DPM2-CDG, B4GALT1-CDG, SLC35A2-CDG, COG1-CDG, COG5-CDG, COG7-CDG, and COG8-CDG.

  4. A comprehensive review of glycosylated bacterial natural products

    PubMed Central

    Elshahawi, Sherif I.; Shaaban, Khaled A.; Kharel, Madan K.

    2015-01-01

    A systematic analysis of all naturally-occurring glycosylated bacterial secondary metabolites reported in the scientific literature up through early 2013 is presented. This comprehensive analysis of 15 940 bacterial natural products revealed 3426 glycosides containing 344 distinct appended carbohydrates and highlights a range of unique opportunities for future biosynthetic study and glycodiversification efforts. PMID:25735878

  5. Glycosylation of CD44 negatively regulates its recognition of hyaluronan

    PubMed Central

    1995-01-01

    Although CD44 is expressed on a wide variety of cell types, few of them use it to recognize the ligand hyaluronan (HA). A glycosylation- defective clone of Chinese hamster ovary cells (Lec 8) bound HA, demonstrating that complete processing of glycoproteins with addition of a full complement of sialic acid is not required. On the contrary, subsequent findings revealed that complex sugars on CD44 can actually inhi