Assay of methylglyoxal-derived protein and nucleotide AGEs

Rabbani, Naila; Shaheen, Fozia; Anwar, Attia; Masania, Jinit; Thornalley, Paul J.

doi:10.1042/bst20140019

Cited by 70 publications

(94 citation statements)

References 16 publications

(22 reference statements)

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“…Protein glycation, oxidation, and nitration adducts were determined by stable isotopic dilution analysis LC-MS/MS using the protocol previously described (70).…”

Section: Methodsmentioning

confidence: 99%

Involvement of a gut–retina axis in protection against dietary glycemia-induced age-related macular degeneration

Rowan

Jiang

Korem

et al. 2017

Proc. Natl. Acad. Sci. U.S.A.

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181

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Age-related macular degeneration (AMD) is the major cause of blindness in developed nations. AMD is characterized by retinal pigmented epithelial (RPE) cell dysfunction and loss of photoreceptor cells. Epidemiologic studies indicate important contributions of dietary patterns to the risk for AMD, but the mechanisms relating diet to disease remain unclear. Here we investigate the effect on AMD of isocaloric diets that differ only in the type of dietary carbohydrate in a wild-type aged-mouse model. The consumption of a high-glycemia (HG) diet resulted in many AMD features (AMDf), including RPE hypopigmentation and atrophy, lipofuscin accumulation, and photoreceptor degeneration, whereas consumption of the lower-glycemia (LG) diet did not. Critically, switching from the HG to the LG diet late in life arrested or reversed AMDf.LG diets limited the accumulation of advanced glycation end products, long-chain polyunsaturated lipids, and their peroxidation end-products and increased C3-carnitine in retina, plasma, or urine. Untargeted metabolomics revealed microbial cometabolites, particularly serotonin, as protective against AMDf. Gut microbiota were responsive to diet, and we identified microbiota in the Clostridiales order as being associated with AMDf and the HG diet, whereas protection from AMDf was associated with the Bacteroidales order and the LG diet. Network analysis revealed a nexus of metabolites and microbiota that appear to act within a gut-retina axis to protect against diet-and age-induced AMDf. The findings indicate a functional interaction between dietary carbohydrates, the metabolome, including microbial cometabolites, and AMDf. Our studies suggest a simple dietary intervention that may be useful in patients to arrest AMD.age-related macular degeneration | glycemic index | advanced glycation end-product | gut microbiome | metabolomics A ge-related macular degeneration (AMD) is the leading cause of irremediable blindness in the industrialized world, with 200 million cases projected by 2020, at a cost of $300 billion (1, 2). Dry AMD accounts for the great majority of cases and is associated with photoreceptor cell loss, often preceded by compromise to the retina pigment epithelium (RPE) cells that nourish and remove waste from the photoreceptors. The etiology of AMD remains an enigma but is clearly multifactorial. Stresses associated with AMD include environment, age, and genetics (3). Frustratingly, there are no early biomarkers to anticipate AMD, and there are no therapies or cure.Recently, we and others observed in epidemiologic studies that, in addition to micronutrients (4-6), macronutrient quality [e.g., consuming a diet with a high glycemic index (GI)] is a significant risk factor for AMD onset and/or progress in nondiabetic humans (7)(8)(9). The GI appears to be an attractive dietary intervention target, because simple replacement of small amounts of high-index foods (such as white bread) with lower-index foods (such as wholegrain bread) can significantly reduce glycemic peaks without requiring ...

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“…Protein glycation, oxidation, and nitration adducts were determined by stable isotopic dilution analysis LC-MS/MS using the protocol previously described (70).…”

Section: Methodsmentioning

confidence: 99%

Involvement of a gut–retina axis in protection against dietary glycemia-induced age-related macular degeneration

Rowan

Jiang

Korem

et al. 2017

Proc. Natl. Acad. Sci. U.S.A.

Self Cite

181

173

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“…Safety assessment of tRES-HESP coformulation was assessed by electrocardiogram and analysis of blood markers. Plasma methylglyoxal and glycation and oxidation adducts in plasma protein and urine (second void after overnight fast) were assayed by stable isotopic dilution analysis liquid chromatography-tandem mass spectrometry (LC-MS/MS) (14,15).…”

Section: Clinical Studymentioning

confidence: 99%

Improved Glycemic Control and Vascular Function in Overweight and Obese Subjects by Glyoxalase 1 Inducer Formulation

et al. 2016

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Risk of insulin resistance, impaired glycemic control, and cardiovascular disease is excessive in overweight and obese populations. We hypothesized that increasing expression of glyoxalase 1 (Glo1)-an enzyme that catalyzes the metabolism of reactive metabolite and glycating agent methylglyoxal-may improve metabolic and vascular health. Dietary bioactive compounds were screened for Glo1 inducer activity in a functional reporter assay, hits were confirmed in cell culture, and an optimized Glo1 inducer formulation was evaluated in a randomized, placebo-controlled crossover clinical trial in 29 overweight and obese subjects. We found trans-resveratrol (tRES) and hesperetin (HESP), at concentrations achieved clinically, synergized to increase Glo1 expression. In highly overweight subjects (BMI >27.5 kg/m 2 ), tRES-HESP coformulation increased expression and activity of Glo1 (27%, P < 0.05) and decreased plasma methylglyoxal (237%, P < 0.05) and total body methylglyoxal-protein glycation (214%, P < 0.01). It decreased fasting and postprandial plasma glucose (25%, P < 0.01, and 28%, P < 0.03, respectively), increased oral glucose insulin sensitivity index (42 mL $ min 21 $ m 22, P < 0.02), and improved arterial dilatation Dbrachial artery flowmediated dilatation/Ddilation response to glyceryl nitrate (95% CI 0.13-2.11). In all subjects, it decreased vascular inflammation marker soluble intercellular adhesion molecule-1 (210%, P < 0.01). In previous clinical evaluations, tRES and HESP individually were ineffective. tRES-HESP coformulation could be a suitable treatment for improved metabolic and vascular health in overweight and obese populations.

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“…Activities of Glo1 and Glo2 were assayed spectrophotometrically, Glo1 protein and Glo1 mRNA were assayed by Western blotting and RT-PCR, and MG, glycation adduct MG-H1 and creatinine were assayed by stable isotopic dilution analysis liquid chromatographytandem mass spectrometry (LC-MS/MS), as described [23,[27][28][29][30]. MG reductase activity was determined spectrophotometrically as described [31] with minor modification: using 1 mM MG as substrate and 50 mM sodium phosphate buffer, pH 7.4 at 37°C, as the assay buffer.…”

Section: Characterisation Of the Glyoxalase System And Methylglyoxal mentioning

confidence: 99%

Reappraisal of putative glyoxalase 1-deficient mouse and dicarbonyl stress on embryonic stem cellsin vitro

Shafie

Xue

Barker

et al. 2016

Biochemical Journal

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Glyoxalase 1 (Glo1) is a cytoplasmic enzyme with a cytoprotective function linked to metabolism of the cytotoxic side product of glycolysis, methylglyoxal (MG). It prevents dicarbonyl stress — the abnormal accumulation of reactive dicarbonyl metabolites, increasing protein and DNA damage. Increased Glo1 expression delays ageing and suppresses carcinogenesis, insulin resistance, cardiovascular disease and vascular complications of diabetes and renal failure. Surprisingly, gene trapping by the International Mouse Knockout Consortium (IMKC) to generate putative Glo1 knockout mice produced a mouse line with the phenotype characterised as normal and healthy. Here, we show that gene trapping mutation was successful, but the presence of Glo1 gene duplication, probably in the embryonic stem cells (ESCs) before gene trapping, maintained wild-type levels of Glo1 expression and activity and sustained the healthy phenotype. In further investigation of the consequences of dicarbonyl stress in ESCs, we found that prolonged exposure of mouse ESCs in culture to high concentrations of MG and/or hypoxia led to low-level increase in Glo1 copy number. In clinical translation, we found a high prevalence of low-level GLO1 copy number increase in renal failure where there is severe dicarbonyl stress. In conclusion, the IMKC Glo1 mutant mouse is not deficient in Glo1 expression through duplication of the Glo1 wild-type allele. Dicarbonyl stress and/or hypoxia induces low-level copy number alternation in ESCs. Similar processes may drive rare GLO1 duplication in health and disease.

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Assay of methylglyoxal-derived protein and nucleotide AGEs

Cited by 70 publications

References 16 publications

Involvement of a gut–retina axis in protection against dietary glycemia-induced age-related macular degeneration

Involvement of a gut–retina axis in protection against dietary glycemia-induced age-related macular degeneration

Improved Glycemic Control and Vascular Function in Overweight and Obese Subjects by Glyoxalase 1 Inducer Formulation

Reappraisal of putative glyoxalase 1-deficient mouse and dicarbonyl stress on embryonic stem cellsin vitro

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