High throughput HPLC–ESI−-MS/MS methodology for mercapturic acid metabolites of 1,3-butadiene: Biomarkers of exposure and bioactivation

Kotapati, Srikanth; Esades, Amanda; Matter, Brock; Le, Chap T.; Tretyakova, Natalia

doi:10.1016/j.cbi.2015.02.009

Cited by 23 publications

(32 citation statements)

References 34 publications

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“…styrene, benzene) (Sanduja, Ansari et al 1989, Boogaard and van Sittert 1995, Ghittori, Maestri et al 1997). Recent advances in LC/MS and related metabolomic technology facilitate the identification and quantification of such potentially useful urinary metabolites (Kotapati, Esades et al 2015, Sterz, Scherer et al 2012, Manini, Andreoli et al 2000). …”

Section: Discussionmentioning

confidence: 99%

In vitrocleavage of diisocyanate-glutathione conjugates by human gamma-glutamyl transpeptidase-1

2015

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Isocyanates differ from many other xenobiotics in their ability to form S-linked conjugates with glutathione (GSH) through direct nucleophilic addition reactions (e.g. without enzymatic “preactivation” and/or transferase activity), potentially predisposing them to metabolism via the mercapturic acid pathway. In vivo, mono-isocyanates are metabolized via the mercapturic acid pathway and excreted as N-acetylated cysteine conjugates, however, the metabolism of di-isocyanates remains unclear. We assessed the ability of purified human γ-glutamyl transpeptidase-1 (GGT-1), a primary enzyme of the mercapturic acid pathway, to cleave S-linked GSH conjugates of 4,4’-methylene diphenyl diisocyanate (MDI) and 1,6-hexamethylene diisocyanate (HDI), two widely used industrial chemicals. A combination of liquid chromatography (LC), tandem mass spectrometry (MS/MS) and hydrogen-deuterium exchange studies confirmed GGT-1 mediated formation of the 607.2 and 525.2 m/z (M+H)+ ions corresponding to bis(cys-gly)-MDI and bis(cys-gly)-HDI, the cleavage products expected from the corresponding bis(GSH)-diisocyanate conjugates. Additional intermediate metabolites and mono(cys-gly)-conjugates with partially hydrolyzed diisocyanate were also observed. Consistent with GGT enzyme kinetics, metabolism proceeded more rapidly under conditions that favored transpeptidation vs. hydrolytic mechanisms of cleavage. Together the data demonstrate the capacity of human GGT-1 to cleave GSH conjugates of both aromatic and aliphatic diisocyanates, suggesting a potential role in their metabolism.

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Section: Discussionmentioning

confidence: 99%

In vitrocleavage of diisocyanate-glutathione conjugates by human gamma-glutamyl transpeptidase-1

2015

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“…Urinary concentrations of MHBMA and DHBMA were determined using previously published HPLC-ESI - -MS/MS methods described in Supplement S1 (9,53). Samples that showed no MHBMA or DHBMA signal were assigned a value corresponding to the limit of detection divided by 2 (0.1 ng/mL urine for MHBMA [9 samples] and 2.5 ng/mL urine for DHBMA [2 samples]).…”

Section: Methodsmentioning

confidence: 99%

Genetic Determinants of 1,3-Butadiene Metabolism and Detoxification in Three Populations of Smokers with Different Risks of Lung Cancer

Boldry

Patel

Kotapati

et al. 2017

Cancer Epidemiology, Biomarkers &Amp; Prevention

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Background 1,3-Butadiene (BD) is an important carcinogen in tobacco smoke that undergoes metabolic activation to DNA-reactive epoxides. These species can be detoxified via glutathione conjugation and excreted in urine as the corresponding N-acetylcysteine conjugates. We hypothesize that single nucleotide polymorphisms in BD-metabolizing genes may change the balance of BD bioactivation and detoxification in White, Japanese American, and African American smokers, potentially contributing to ethnic differences in lung cancer risk. Methods We measured the levels of BD metabolites, 1- and 2-(N-acetyl-L-cystein-S-yl)-1-hydroxybut-3-ene (MHBMA) and N-acetyl-S-(3,4-dihydroxybutyl)-L-cysteine (DHBMA), in urine samples from a total of 1,072 White, Japanese American, and African American smokers and adjusted these values for body mass index, age, batch, and total nicotine equivalents. We also conducted a genome wide association study to identify genetic determinants of BD metabolism. Results We found that mean urinary MHBMA concentrations differed significantly by ethnicity (p = 4.0 × 10−25). African Americans excreted the highest levels of MHBMA followed by Whites and Japanese Americans. MHBMA levels were affected by GSTT1 gene copy number (p < 0.0001); conditional on GSTT1, no other polymorphisms showed a significant association. Urinary DHBMA levels also differed between ethnic groups (p = 3.3 ×10−4), but were not affected by GSTT1 copy number (p = 0.226). Conclusions GSTT1 gene deletion has a strong effect on urinary MHBMA levels, and therefore BD metabolism, in smokers. Impact Our results show that the order of MHBMA levels among ethnic groups is consistent with their respective lung cancer risk and can be partially explained by GSTT1 genotype.

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“…Mercapturic acids are formed as metabolites of a host of chemicals and their formation and excretion may serve as biomarkers for exposure (De Rooij et al 1998;Perbellini et al 2002;Haufroid and Lison 2005;Kotapati et al 2015). Reviews of LC-MS methods for quantifying the excretion of mercapturic acids demonstrates the potential utility of mercapturic acid formation and excretion as biomarkers B'Hymer 2014, 2016).…”

Section: Mercapturic Acids As Biomarkersmentioning

confidence: 99%

The mercapturic acid pathway

Hanna

Anders

2019

Critical Reviews in Toxicology

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The mercapturic acid pathway is a major route for the biotransformation of xenobiotic and endobiotic electrophilic compounds and their metabolites. Mercapturic acids (N-acetyl-L-cysteine S-conjugates) are formed by the sequential action of the glutathione transferases, c-glutamyltransferases, dipeptidases, and cysteine S-conjugate N-acetyltransferase to yield glutathione S-conjugates, L-cysteinylglycine S-conjugates, L-cysteine S-conjugates, and mercapturic acids; these metabolites constitute a "mercapturomic" profile. Aminoacylases catalyze the hydrolysis of mercapturic acids to form cysteine S-conjugates. Several renal transport systems facilitate the urinary elimination of mercapturic acids; urinary mercapturic acids may serve as biomarkers for exposure to chemicals. Although mercapturic acid formation and elimination is a detoxication reaction, L-cysteine S-conjugates may undergo bioactivation by cysteine Sconjugate b-lyase. Moreover, some L-cysteine S-conjugates, particularly L-cysteinyl-leukotrienes, exert significant pathophysiological effects. Finally, some enzymes of the mercapturic acid pathway are described as the so-called "moonlighting proteins," catalytic proteins that exert multiple biochemical or biophysical functions apart from catalysis.

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High throughput HPLC–ESI−-MS/MS methodology for mercapturic acid metabolites of 1,3-butadiene: Biomarkers of exposure and bioactivation

Cited by 23 publications

References 34 publications

In vitrocleavage of diisocyanate-glutathione conjugates by human gamma-glutamyl transpeptidase-1

In vitrocleavage of diisocyanate-glutathione conjugates by human gamma-glutamyl transpeptidase-1

Genetic Determinants of 1,3-Butadiene Metabolism and Detoxification in Three Populations of Smokers with Different Risks of Lung Cancer

The mercapturic acid pathway

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