scholarly journals Effect of dicarbonyl-induced browning on alpha-crystallin chaperone-like activity: physiological significance and caveats of in vitro aggregation assays

2004 ◽  
Vol 379 (2) ◽  
pp. 273-282 ◽  
Author(s):  
M. Satish KUMAR ◽  
P. Yadagiri REDDY ◽  
P. Anil KUMAR ◽  
Ira SUROLIA ◽  
G. Bhanuprakash REDDY
Keyword(s):  
Advanced Glycation End Products ◽  
Molecular Chaperone ◽  
Structural Changes ◽  
Surface Hydrophobicity ◽  
Enzyme Inactivation ◽  
Advanced Glycation ◽  
Glycation End Products ◽  
End Products ◽  
Enzymic Browning

α-Crystallin is a member of the small heat-shock protein family and functions like a molecular chaperone, and may thus help in maintaining the transparency of the eye lens by protecting the lens proteins from various stress conditions. Non-enzymic glycation of long-lived proteins has been implicated in several age- and diabetes-related complications, including cataract. Dicarbonyl compounds such as methylglyoxal and glyoxal have been identified as the predominant source for the formation of advanced glycation end-products in various tissues including the lens. We have investigated the effect of non-enzymic browning of α-crystallin by reactive dicarbonyls on its molecular chaperone-like function. Non-enzymic browning of bovine α-crystallin in vitro caused, along with altered secondary and tertiary structures, cross-linking and high-molecular-mass aggregation. Notwithstanding these structural changes, methylglyoxal- and glyoxal-modified α-crystallin showed enhanced anti-aggregation activity in various in vitro aggregation assays. Paradoxically, increased chaperone-like activity of modified α-crystallin was not associated with increased surface hydrophobicity and rather showed less 8-anilinonaphthalene-l-sulphonic acid binding. In contrast, the chaperone-like function of modified α-crystallin was found to be reduced in assays that monitor the prevention of enzyme inactivation by UV-B and heat. Moreover, incubation of bovine lens with methylglyoxal in organ culture resulted in cataract formation with accumulation of advanced glycation end-products and recovery of α-crystallin in high proportions in the insoluble fraction. Furthermore, soluble α-crystallin from methylglyoxal-treated lenses showed decreased chaperone-like activity. Thus, in addition to describing the effects of methylglyoxal and glyoxal on structure and chaperone-like activity, our studies also bring out an important caveat of aggregation assays in the context of the chaperone function of α-crystallin.

scholarly journals Health Promoting Effect of Phyllanthus emblica and Azadiractha indica against Advanced Glycation End Products Formation

2021 ◽  
Vol 11 (19) ◽  
pp. 8819
Author(s):  
Mohammed A. Alsahli ◽  
Shehwaz Anwar ◽  
Faisal M. Alzahrani ◽  
Ahmad Almatroudi ◽  
Hani Alfheeaid ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Advanced Glycation End Products ◽  
Structural Changes ◽  
Therapeutic Potential ◽  
Health Problems ◽  
Phyllanthus Emblica ◽  
Advanced Glycation ◽  
Glycation End Products ◽  
End Products

Oxidative stress is linked with inflammation, diabetic complications, and advanced glycation end products formation. Intake of flavonoid-rich foods has been reported to have a beneficial effect on human health. The aim of this study was to verify the therapeutic potential of Phyllanthusemblica and Azadiractha indica against glycation and other oxidative stress-induced complications such as inflammation using in vitro study. Ethanol extracts of Phyllanthus emblica fruit pulp and dried leaf of Azadiractha indica were prepared to investigate in vitro anti-inflammatory and anti-glycating potentials. In a DPPH assay, the EC50 value of extract of P. emblica and A. indica was found to be 1532.36 ± 0.17 and 1380.61 ± 0.27 µg/mL, respectively. The FRAP value of P. emblica and A. indica extract was 86.6 and 32.12 µg ascorbic acid/100 mg dry weight of the extract. The maximum percentage of H2O2 scavenging activity was 71.30% and 67.38%, respectively. Extracts of P. emblica and A. indica showed maximum inhibition of heat-induced BSA denaturation by 62.42% and 53.00%, heat-induced denaturation of egg albumin, by 50.84%% and 44.31%, and heat-induced hemolysis by 54.44% and 50.21%. Both extracts (600 µg/mL) significantly reduced the browning, structural changes, aggregation, and AGEs formation. Our biophysical studies confirmed the AGEs formation was inhibiting the potential of extracts. Thus, our findings confirm that these extracts are a rich source of antioxidants and may be utilized to prevent the oxidative stress-induced destruction of biomolecules, glycation, and in the therapy of a variety of health problems, including inflammation. Further, a combination of extracts of P. emblica and A. indica may be extremely useful in preventing and treating health problems.

Sulforaphane inhibits formation of advanced glycation end products in vitro

2014 ◽  
Vol 1 (e1) ◽  
pp. 001-001 ◽  
Author(s):  
Kei Fukami ◽  
Takanori Matsui ◽  
Sho-ichi Yamagishi
Keyword(s):  
Advanced Glycation End Products ◽  
Advanced Glycation ◽  
Glycation End Products ◽  
End Products

scholarly journals Influence of Dopamine on Fluorescent Advanced Glycation End Products Formation Using Drosophila melanogaster

Biomolecules ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 453
Author(s):  
Ana Filošević Vujnović ◽  
Katarina Jović ◽  
Emanuel Pištan ◽  
Rozi Andretić Waldowski
Keyword(s):  
Drosophila Melanogaster ◽  
Advanced Glycation End Products ◽  
Model Organism ◽  
Covalent Modification ◽  
Advanced Glycation ◽  
Biomarkers Of Aging ◽  
Glycation End Products ◽  
End Products

Non-enzymatic glycation and covalent modification of proteins leads to Advanced Glycation End products (AGEs). AGEs are biomarkers of aging and neurodegenerative disease, and can be induced by impaired neuronal signaling. The objective of this study was to investigate if manipulation of dopamine (DA) in vitro using the model protein, bovine serum albumin (BSA), and in vivo using the model organism Drosophila melanogaster, influences fluorescent AGEs (fAGEs) formation as an indicator of dopamine-induced oxidation events. DA inhibited fAGEs-BSA synthesis in vitro, suggesting an anti-oxidative effect, which was not observed when flies were fed DA. Feeding flies cocaine and methamphetamine led to increased fAGEs formation. Mutants lacking the dopaminergic transporter or the D1-type showed further elevation of fAGEs accumulation, indicating that the long-term perturbation in DA function leads to higher production of fAGEs. To confirm that DA has oxidative properties in vivo, we fed flies antioxidant quercetin (QUE) together with methamphetamine. QUE significantly decreased methamphetamine-induced fAGEs formation suggesting that the perturbation of DA function in vivo leads to increased oxidation. These findings present arguments for the use of fAGEs as a biomarker of DA-associated neurodegenerative changes and for assessment of antioxidant interventions such as QUE treatment.

scholarly journals Advanced glycation end products induce a prothrombotic phenotype in mice via interaction with platelet CD36

Blood ◽  
2012 ◽  
Vol 119 (25) ◽  
pp. 6136-6144 ◽  
Author(s):  
Weifei Zhu ◽  
Wei Li ◽  
Roy L. Silverstein
Keyword(s):  
Diabetes Mellitus ◽  
Mouse Models ◽  
Advanced Glycation End Products ◽  
Vascular Complications ◽  
Dependent Manner ◽  
Advanced Glycation ◽  
Drug Induced ◽  
Glycation End Products ◽  
End Products

Abstract Diabetes mellitus has been associated with platelet hyperreactivity, which plays a central role in the hyperglycemia-related prothrombotic phenotype. The mechanisms responsible for this phenomenon are not established. In the present study, we investigated the role of CD36, a class-B scavenger receptor, in this process. Using both in vitro and in vivo mouse models, we demonstrated direct and specific interactions of platelet CD36 with advanced glycation end products (AGEs) generated under hyperglycemic conditions. AGEs bound to platelet CD36 in a specific and dose-dependent manner, and binding was inhibited by the high-affinity CD36 ligand NO2LDL. Cd36-null platelets did not bind AGE. Using diet- and drug-induced mouse models of diabetes, we have shown that cd36-null mice had a delayed time to the formation of occlusive thrombi compared with wild-type (WT) in a FeCl3-induced carotid artery injury model. Cd36-null mice had a similar level of hyperglycemia and a similar level of plasma AGEs compared with WT mice under this condition, but WT mice had more AGEs incorporated into thrombi. Mechanistic studies revealed that CD36-dependent JNK2 activation is involved in this prothrombotic pathway. Therefore, the results of the present study couple vascular complications in diabetes mellitus with AGE-CD36–mediated platelet signaling and hyperreactivity.

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