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The anti-apoptotic activity of albumin for endothelium is inhibited by advanced glycation end products restricting intramolecular movement. Cell Mol Biol Lett 2009; 14:575-86. [PMID: 19484197 PMCID: PMC6275583 DOI: 10.2478/s11658-009-0021-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2008] [Accepted: 05/16/2009] [Indexed: 01/15/2023] Open
Abstract
Human serum albumin (HSA) inhibits endothelial apoptosis in a highly specific manner. CNBr fragmentation greatly increases the effectiveness of this activity, suggesting that this type of protection is mediated by a partially cryptic albumin domain which is transiently exposed by intramolecular movement. Advanced glycation end-product (AGE) formation in HSA greatly reduces its intra-molecular movement. This study aimed to determine if this inhibits the anti-apoptotic activity of HSA, and if such inactivation could be reversed by CNBr fragmentation. HSA-AGE was prepared by incubating HSA with glucose, and assessed using the fructosamine assay, mass spectrometry, SDS-PAGE and fluorometry. Low levels of AGE in the HSA had little effect upon its anti-apoptotic activity, but when the levels of AGE were high and the intra-molecular movement was reduced, endothelial cell survival was also found to be reduced to levels equivalent to those in cultures without HSA or serum (p > 0.001). Survival was restored by the inclusion of native HSA, despite the presence of HSA with high levels of AGE. Also, CNBr fragmentation of otherwise inactive HSA-AGE restored the anti-apoptotic activity for endothelium. Apoptosis was confirmed by DNA gel electrophoresis, transmission electron microscopy and fluorescence-activated cell sorting analysis, and there was no evidence for direct toxicity in the HSA-AGE preparations. The results are consistent with the proposed role of intra-molecular movement in exposing the anti-apoptotic domain in HSA for endothelium. The levels of AGE formation required to inhibit the anti-apoptotic activity of HSA exceeded those reported for diabetes. Nonetheless, the data from this study seems to be the first example of reduced protein function due to AGE-restricted intra-molecular movement.
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Bras ID, Colitz CMH, Kusewitt DF, Chandler H, Lu P, Gemensky-Metzler AJ, Wilkie DA. Evaluation of advanced glycation end-products in diabetic and inherited canine cataracts. Graefes Arch Clin Exp Ophthalmol 2007; 245:249-57. [PMID: 16896921 DOI: 10.1007/s00417-006-0293-7] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2005] [Revised: 12/06/2005] [Accepted: 01/27/2006] [Indexed: 11/24/2022] Open
Abstract
BACKGROUND The receptor for advanced glycation end-products (RAGE) increases in the human cataract and should correlate with increased DNA damage and proliferation of lens epithelial cells (LECs). The purpose of this study was to measure and immunolocalize RAGE in normal and cataractous canine LECs, and to determine whether there was a correlation between RAGE and DNA damage (gadd45), cell-cycle regulation (p21), and LEC proliferation (proliferating cell nuclear antigen, PCNA). METHODS Thirty-two anterior lens capsules from 22 dogs that underwent cataract surgery and 10 lenses from dogs with normal eyes were evaluated. Eleven of the cataractous lenses were from diabetic patients (n=16), and eleven were from patients with inherited cataracts (n=16). Standard immunohistochemical staining was performed using antibodies against RAGE, gadd45, p21, PCNA, alpha-smooth muscle actin, and TGF-beta. Immunostaining intensity for each antibody was given a score of 0-4+. Standard Western blot analysis on normal and cataractous lens capsules was performed using the same antibodies as in the immunohistochemical staining. Comparisons were also made based on age and sex. Real-time reverse transcriptase-polymerase chain reaction (qRT-PCR) was performed for RAGE. RESULTS There was an increase in RAGE expression with age in normal LECs, but no significant difference was seen when normal adult LECs were compared to cataractous LECs. The stage of the cataract and the presence of LIU were not associated with a significant increase in RAGE expression. There was no age-dependent difference in the normal lenses for gadd45, p21, or PCNA. Significant up-regulation of p21 (P < 0.05) and PCNA (P < 0.05) was seen in diabetic cataracts compared to inherited cataracts. CONCLUSION RAGE and PCNA expression did not increase with cataractogenesis, possibly due to overexpression associated with normal aging and constant exposure to oxidative stress from sunlight-related ultraviolet irradiation, respectively. However, p21 and PCNA increased in diabetic cataractogenesis suggesting cell cycle and proliferation dysregulation. This may be related to the rapid onset in this type of cataract compared with the more chronic and slower-to-develop inherited cataracts.
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Affiliation(s)
- I Dineli Bras
- Department of Veterinary Clinical Sciences, The Ohio State University College of Veterinary Medicine, Columbus, OH 43210, USA
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DeGroot J, Verzijl N, Wenting-van Wijk MJG, Jacobs KMG, Van El B, Van Roermund PM, Bank RA, Bijlsma JWJ, TeKoppele JM, Lafeber FPJG. Accumulation of advanced glycation end products as a molecular mechanism for aging as a risk factor in osteoarthritis. ACTA ACUST UNITED AC 2004; 50:1207-15. [PMID: 15077303 DOI: 10.1002/art.20170] [Citation(s) in RCA: 152] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
OBJECTIVE Osteoarthritis (OA) is one of the most prevalent and disabling chronic conditions affecting the elderly. Its etiology is largely unknown, but age is the most prominent risk factor. The current study was designed to test whether accumulation of advanced glycation end products (AGEs), which are known to adversely affect cartilage turnover and mechanical properties, provides a molecular mechanism by which aging contributes to the development of OA. METHODS The hypothesis that elevated AGE levels predispose to the development of OA was tested in the canine anterior cruciate ligament transection (ACLT) model of experimental OA. Cartilage AGE levels were enhanced in young dogs by intraarticular injections of ribose. This mimics the accumulation of AGEs without the interference of other age-related changes. The severity of OA was then assessed 7 weeks after ACLT surgery in dogs with normal versus enhanced AGE levels. RESULTS Intraarticular injections of ribose enhanced cartilage AGE levels approximately 5-fold, which is similar to the normal increase that is observed in old dogs. ACLT surgery resulted in more-pronounced OA in dogs with enhanced AGE levels. This was observed as increased collagen damage and enhanced release of proteoglycans. The attempt to repair the matrix damage was impaired; proteoglycan synthesis and retention were decreased at enhanced AGE levels. Mankin grading of histology sections also revealed more-severe OA in animals with enhanced AGE levels. CONCLUSION These findings demonstrate increased severity of OA at higher cartilage AGE levels and provide the first in vivo experimental evidence for a molecular mechanism by which aging may predispose to the development of OA.
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Affiliation(s)
- Jeroen DeGroot
- Gaubius Laboratory, TNO Prevention and Health, Leiden, The Netherlands.
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Yamauchi Y, Ejiri Y, Tanaka K. Glycation by ascorbic acid causes loss of activity of ribulose-1,5-bisphosphate carboxylase/oxygenase and its increased susceptibility to proteases. PLANT & CELL PHYSIOLOGY 2002; 43:1334-1341. [PMID: 12461133 DOI: 10.1093/pcp/pcf162] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Glycation is a process whereby sugar molecules form a covalent adduct with protein amino groups. In this study, we used ascorbic acid (AsA) as a glycating agent and purified cucumber (Cucumis sativus L.) ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) as a model protein in chloroplast tissues, and examined effects of glycation on the activity and susceptibility of Rubisco to proteases. Glycation proceeded via two phases during incubation with AsA and Rubisco in vitro at physiological conditions (10 mM AsA, pH 7.5, 25 degrees C in the presence of atmospheric oxygen). At the early stage of glycation (phase 1), the amount of AsA attaching to Rubisco increased at an almost linear rate (0.5-0.7 mol AsA incorporated (mol Rubisco)(-1) d(-1)). By Western blotting using monoclonal antibodies recognizing glycation adducts, a major glycation adduct, N( epsilon )-(carboxymethyl)lysine was detected. At the late stage of glycation (phase 2), incorporation of AsA reached saturation, and a glycation adduct, pentosidine mediating intramolecular cross-linking, was detected corresponding to formation of high molecular weight aggregates cross-linked between subunits. Glycation led to a decrease in Rubisco activity (half-life about 7-8 d). Furthermore, glycated Rubisco of phase 2 drastically increased protease susceptibility in contrast to unchanged susceptibility of glycated Rubisco of phase 1 compared to that of native Rubisco. Results obtained here suggest that AsA is possibly an important factor in the loss of activity and turnover of Rubisco.
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Affiliation(s)
- Yasuo Yamauchi
- Laboratory of Plant Biotechnology, Faculty of Agriculture, Tottori University, Koyama, Tottori, 680-8553 Japan.
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Abstract
Bio-reactive advanced glycation endproducts (AGE) alter the structure and function of molecules in biological systems and increase oxidative stress. These adverse effects of both exogenous and endogenously derived AGE have been implicated in the pathogenesis of diabetic complications and changes associated with ageing including atherosclerosis, renal, eye and neurological disease. Specific AGE receptors and nonreceptor mechanisms contribute to these processes but also assist in the removal and degradation of AGE. The final disposal of AGE depends on renal clearance. Promising pharmacologic strategies to prevent AGE formation, reduce AGE toxicity, and/or inactivate AGE are under investigation.
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Affiliation(s)
- H Vlassara
- Department of Geriatrics, Mount Sinai School of Medicine, NY 10029, USA.
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Abstract
Hypertension and aging adversely affect cardiovascular system and the heart is invariably involved. Manifestations of hypertensive heart disease and of the aging heart appear similar; ventricular hypertrophy, myocardial fibrosis, and impairments in ventricular function and coronary hemodynamics characterize both conditions. However, a great deal of evidence suggests that different underlying pathophysiological mechanisms may be involved. This report discusses most recent clinical and experimental findings and focuses on the alterations in nonmyocytic elements that are a part of heart involvement. Particular attention was given to factors that are responsible for exaggerated myocardial deposition of collagen that, by itself, may be responsible for ventricular dysfunction and impaired coronary hemodynamics in hypertensive and aging hearts. Newly developed therapeutical strategies, based on the most recent experimental and clinical studies, are also discussed.
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Affiliation(s)
- J Varagic
- Hypertension Research Laboratory, Alton Ochsner Medical Foundation, New Orleans, Louisiana 70121, USA
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Zoellner H, Hou JY, Hochgrebe T, Poljak A, Duncan MW, Golding J, Henderson T, Lynch G. Fluorometric and mass spectrometric analysis of nonenzymatic glycosylated albumin. Biochem Biophys Res Commun 2001; 284:83-9. [PMID: 11374874 DOI: 10.1006/bbrc.2001.4924] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Albumin is the major transport protein in blood and intramolecular movement contributes to this function. Nonenzymatic glycosylation (NEG) of albumin occurs in diabetes and, in this study, fluorometric methods were used to determine the effect of increasing levels of NEG upon intramolecular movement in human serum albumin. Low levels of NEG significantly reduced and left-shifted Trp fluorescence, reduced quenching by acrylamide and inhibited penetration of bis-ANS, while these changes became only modestly more pronounced at higher levels of NEG. Mass spectrometry of tryptic and CNBr NEG-HSA fragments identified potential glycosylation sites and demonstrated only late glycosylation of the C- and N-terminal regions of the protein. Similar changes in diabetes may contribute to altered transport function in these patients.
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Affiliation(s)
- H Zoellner
- Department of Oral Pathology and Oral Medicine, University of Sydney, Westmead Hospital Dental Clinical School, New South Wales, Australia.
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Fayle S, Gerrard J, Simmons L, Meade S, Reid E, Johnston A. Crosslinkage of proteins by dehydroascorbic acid and its degradation products. Food Chem 2000. [DOI: 10.1016/s0308-8146(00)00077-7] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Nawroth PP, Bierhaus A, Vogel GE, Hofmann MA, Zumbach M, Wahl P, Ziegler R. [Non-enzymatic glycation and oxidative stress in chronic illnesses and diabetes mellitus]. MEDIZINISCHE KLINIK (MUNICH, GERMANY : 1983) 1999; 94:29-38. [PMID: 10081287 DOI: 10.1007/bf03044692] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
UNLABELLED New approaches in biochemistry and molecular biology have increased the knowledge on the pathophysiology of chronic diseases as late diabetic complications, Alzheimer's disease, arteriosclerosis and vascular disease by defining the concept of "AGE-formation and oxidative stress." Nonenzymatic glycation, in which reducing sugars are covalently bound to free aminogroups of macromolecules, results in the formation of Advanced Glycation End products (AGEs) which accumulate during aging and at accelerated rate during the course of diabetes. Glycation accompanying oxidation processes support AGE-formation. AGE-formation changes the physicochemical properties of proteins, lipids and nucleic acids. In addition, binding of AGEs to specific surface receptors induces cellular signalling and cell activation. Interaction of AGEs with one of the receptors, RAGE, generates intracellular oxidative stress, which results in activation of the transcription factor NF-kappa B and subsequent gene expression, which might be relevant in late diabetic complications. CONCLUSION Knowledge of the basis molecular mechanisms allows to understand the interplay of different inducers such as redicals, cytokines, AGE-proteins and amyloid-beta-peptids and to define oxidative stress as a "common endpoint" of cell dysfunction. With respect to therapeutic options it is now possible not only to optimize blood glycemic control, but also to design drugs such as AGE-inhibitors and AGE-"cross-link" breakers. In addition patients with chronic disease associated with increased oxidative stress ay benefit from an antioxidant rich (and AGE protein poor?) nutrition.
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Affiliation(s)
- P P Nawroth
- Abteilung Innere Medizin I, Endokrinologie und Stoffwechsel, Universität Heidelberg.
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Costantino L, Rastelli G, Vianello P, Cignarella G, Barlocco D. Diabetes complications and their potential prevention: aldose reductase inhibition and other approaches. Med Res Rev 1999; 19:3-23. [PMID: 9918192 DOI: 10.1002/(sici)1098-1128(199901)19:1<3::aid-med2>3.0.co;2-7] [Citation(s) in RCA: 136] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Despite recent advances both in the chemistry and molecular pharmacology of antidiabetic drugs, diabetes still remains a life-threatening disease, which tends to spread all over the world. The clinical profile of diabetic subjects is often worsened by the presence of several long-term complications, namely neuropathy, nephropathy, retinopathy, and cataract. Several attempts have been made to prevent or at least to delay them. The most relevant are reported in this review, including the development of compounds acting as aldose reductase inhibitors, anti-advanced glycation end-product drugs, free radical scavengers, vasoactive agents, essential fatty acid supplementation, and neurotropic growth factors.
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Affiliation(s)
- L Costantino
- Dipartimento di Scienze Farmaceutiche, Modena, Italy
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Wolffenbuttel BH, Boulanger CM, Crijns FR, Huijberts MS, Poitevin P, Swennen GN, Vasan S, Egan JJ, Ulrich P, Cerami A, Lévy BI. Breakers of advanced glycation end products restore large artery properties in experimental diabetes. Proc Natl Acad Sci U S A 1998; 95:4630-4. [PMID: 9539789 PMCID: PMC22541 DOI: 10.1073/pnas.95.8.4630] [Citation(s) in RCA: 321] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Glucose and other reducing sugars react with proteins by a nonenzymatic, posttranslational modification process called nonenzymatic glycation. The formation of advanced glycation end products (AGEs) on connective tissue and matrix components accounts largely for the increase in collagen crosslinking that accompanies normal aging and which occurs at an accelerated rate in diabetes, leading to an increase in arterial stiffness. A new class of AGE crosslink "breakers" reacts with and cleaves these covalent, AGE-derived protein crosslinks. Treatment of rats with streptozotocin-induced diabetes with the AGE-breaker ALT-711 for 1-3 weeks reversed the diabetes-induced increase of large artery stiffness as measured by systemic arterial compliance, aortic impedance, and carotid artery compliance and distensibility. These findings will have considerable implications for the treatment of patients with diabetes-related complications and aging.
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MESH Headings
- Animals
- Blood Flow Velocity
- Blood Pressure
- Cardiac Output
- Carotid Artery, Common/drug effects
- Carotid Artery, Common/physiology
- Carotid Artery, Common/physiopathology
- Collagen/metabolism
- Cross-Linking Reagents
- Diabetes Mellitus, Experimental/blood
- Diabetes Mellitus, Experimental/physiopathology
- Glycation End Products, Advanced/metabolism
- Heart Rate
- Hemodynamics/drug effects
- In Vitro Techniques
- Male
- Muscle, Smooth, Vascular/drug effects
- Muscle, Smooth, Vascular/physiology
- Muscle, Smooth, Vascular/physiopathology
- Rats
- Rats, Wistar
- Thiazoles/pharmacology
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Affiliation(s)
- B H Wolffenbuttel
- Department of Endocrinology, Cardiovascular Research Institute Maastricht and University (Hospital) Maastricht, P.O. Box 5800, 6202 AZ Maastricht, The Netherlands
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Medina L, Haltiwanger RS. Calf thymus high mobility group proteins are nonenzymatically glycated but not significantly glycosylated. Glycobiology 1998; 8:191-8. [PMID: 9451029 DOI: 10.1093/glycob/8.2.191] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Over the past decade, there have been many reports suggesting the presence of complex carbohydrates on nuclear and cytoplasmic proteins in mammalian cells. Some of the most often cited of these reports deal with the glycosylation of the high mobility group (HMG) proteins. These are relatively abundant chromosomal proteins that are known to be associated with nucleosomes and actively transcribed regions of chromatin. The original report describing HMG protein glycosylation presented several lines of evidence suggesting that these proteins are glycosylated, including carbohydrate compositional analysis and periodic-acid Schiff staining. We have attempted to repeat these observations with more highly purified protein than was utilized in the original study. Using carbohydrate compositional analysis performed by high pH anion exchange chromatography coupled to pulsed-amperometric detection, we saw no evidence for significant glycosylation of these proteins. In addition, we found no evidence for the presence of O-GlcNAc, a well known form of nuclear glycosylation. The HMG proteins did react with periodate, suggesting the presence of a modification containing cis-diols on the protein. Several tryptic peptides isolated from HMG 14 and 17 which retained the periodate reactivity had in common lysine residues, suggesting a potential modification of the straightepsilon-amino groups of lysines such as nonenzymatic glycation. Western blot analysis of the HMG proteins using anti-advanced glycation endproducts (AGE) antibodies confirmed the presence of glycation products on the HMG proteins.
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Affiliation(s)
- L Medina
- Department of Biochemistry and Cell Biology, Institute for Cell and Developmental Biology, State University of New York at Stony Brook 11794-5215, USA
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