Tandem MS Analysis of Model Peptide Adducts from Reactive Metabolites of the Hepatotoxin 1,1-Dichloroethylene

Jones, Juliet A.; Liebler, Daniel C.

doi:10.1021/tx000148w

Cited by 12 publications

(12 citation statements)

References 17 publications

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“…Searches also were performed for GSCOCH 2 - S -cys-protein adducts. These adducts previously had been identified in vitro and their MS-MS fragmentation patterns were characterized extensively ( , ). A search of the data for these characteristic fragmentation patterns using the pattern recognition algorithm SALSA () did not reveal the presence of any peptides containing this modification.…”

Section: Resultsmentioning

confidence: 99%

“…Reaction of the latter with glutathione forms ClCH 2 COSG, which is more stable than ClCH 2 COCl, yet is capable of alkylating GSH to form the bis-glutathionyl conjugate GSCOCH 2 SG. Alternatively, ClCH 2 COSG can alkylate cysteine-containing peptides to form GSCOCH 2 - S -cys-peptide adducts ( , ). GSCH 2 COSG can further hydrolyze to GSCH 2 CO 2 H, which presumably yields the observed in vivo urinary metabolites S -carboxymethylcysteine, N -acetyl- S -carboxymethyl cysteine, and thiodiglycolic acid.…”

Section: Introductionmentioning

confidence: 99%

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Proteomic Characterization of Metabolites, Protein Adducts, and Biliary Proteins in Rats Exposed to 1,1-Dichloroethylene or Diclofenac

Jones

Kaphalia

Treinen-Moslen

et al. 2003

Chem. Res. Toxicol.

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A proteome profiling approach was used to compare effects of two toxicants, 1,1-dicloroethylene (DCE) and diclofenac, which covalently adduct hepatic proteins. Bile was examined as a potential source of protein alterations since both toxicants target the hepatic biliary canaliculus. Bile was collected before and after toxicant treatment. Biliary proteins were separated by one-dimensional SDS-PAGE and analyzed by liquid chromatography-tandem mass spectrometry (LC-MS-MS) with data-dependent scanning. Comprehensive analysis of biliary proteins was performed by using SEQUEST and BLAST database searching, in combination with de novo interpretation. Bile not subjected to tryptic digestion was analyzed for DCE metabolites. DCE treatment resulted in a marked increase in the overall number of biliary proteins, whereas few changes in the proteomic profile were apparent in bile after diclofenac treatment. This is consonant with prior observations of more profound effects of DCE on canalicular membrane integrity. LC-MS-MS analyses for DCE metabolites revealed the presence of S-carboxymethyl glutathione, S-(cysteinylacetyl)glutathione, and a product of the intramolecular rearrangement of the DCE metabolite, ClCH(2)COSG, not previously described in vivo. In addition, several S-carboxymethylated proteins were identified in bile from DCE-treated animals. This investigation has produced the first comprehensive baseline characterization of the content of the rat biliary proteome and the first documentation of alterations in the proteome of bile by toxicant treatment. In addition, the results provide direct in vivo evidence for DCE metabolic routes proposed in the formation of covalent adducts.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Proteomic Characterization of Metabolites, Protein Adducts, and Biliary Proteins in Rats Exposed to 1,1-Dichloroethylene or Diclofenac

Jones

Kaphalia

Treinen-Moslen

et al. 2003

Chem. Res. Toxicol.

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“…Although there is a reasonably well-populated database of proteins which have been shown to be covalently modified by a range of metabolically activated toxicants [1], as well as amino acids in proteins identified as targets of numerous reactive metabolites [2, 3], there still remains a general lack of appreciation for the precise mechanisms by which these modifications subsequently lead to cytotoxic events in a cell. There have been several studies showing modifications of specific amino acids in a protein following direct addition of reactive metabolites to solutions of protein [2–4], however specific residues modified by reactive metabolites generated in a whole cell or an in vivo system have only been identified in a few instances [5–7].…”

Section: Introductionmentioning

confidence: 99%

“…There have been several studies showing modifications of specific amino acids in a protein following direct addition of reactive metabolites to solutions of protein [2–4], however specific residues modified by reactive metabolites generated in a whole cell or an in vivo system have only been identified in a few instances [5–7]. This limited knowledge of reactive metabolite adduction onto proteins in cellular systems is, in part, due to mixture complexity as well as the generally small degree of modification resulting from the reactive metabolites.…”

Section: Introductionmentioning

confidence: 99%

Analysis of naphthalene adduct binding sites in model proteins by tandem mass spectrometry

Pham

Jewell

Morin

et al. 2012

Chemico-Biological Interactions

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The electrophilic metabolites of the polyaromatic hydrocarbon naphthalene have been shown to bind covalently to proteins and covalent adduct formation correlates with the cytotoxic effects of the chemical in the respiratory system. Although 1,2-naphthalene epoxide, naphthalene diol epoxide, 1,2-naphthoquinone, and 1,4-napthoquinone have been identified as reactive metabolites of interest, the role of each metabolite in total covalent protein adduction and subsequent cytotoxicity remains to be established. To better understand the target residues associated with the reaction of these metabolites with proteins, mass spectrometry was used to identify adducted residues following 1) incubation of metabolites with actin and protein disulfide isomerase (PDI), and 2) activation of naphthalene in microsomal incubations containing supplemental actin or PDI. All four reactive metabolites bound to Cys, Lys or His residues in actin and PDI. Cys17 of actin was the only residue adducted by all metabolites; there was substantial metabolite selectivity for the majority of adducted residues. Modifications of actin and PDI, following microsomal incubations containing 14C-naphthalene, were detected readily by 2D gel electrophoresis and phosphor imaging. However, target modifications on tryptic peptides from these isolated proteins could not be readily detected by MALDI/TOF/TOF and only three modified peptides were detected using high resolution – selective ion monitoring (HR-SIM). All the reactive metabolites investigated have the potential to modify several residues in a single protein, but even in tissues with very high rates of naphthalene activation, the extent of modification was too low to allow unambiguous identification of a significant number of modified residues in the isolated proteins.

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“…Martin et al (2003) report that mitochondrial dysfunction is an early event in hepatotoxicity. DCE electrophilic metabolites can damage hepatocytes (Jones and Liebler, 2000) and renal tubular cells (Brittebo et al, 1993) by binding covalently to their proteins and nucleic acids. DCE cytotoxicity and covalent binding are greatest in murine cells with the highest CYP2E1 content, namely, centrilobular hepatocytes, bronchiolar Clara cells, and renal proximal tubular cells (Speerschneider and Dekant, 1995;Forkert, 2001).…”

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confidence: 99%

Influence of Exposure Route and Oral Dosage Regimen on 1, 1-Dichloroethylene Toxicokinetics and Target Organ Toxicity

Bruckner¹,

White²,

Muralidhara³

et al. 2010

J Pharmacol Exp Ther

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The objective of this investigation was to elucidate the effects of route of exposure and oral dosage regimen on the toxicokinetics (TK) of 1,1-dichloroethylene (DCE). Fasted male Sprague-Dawley rats that inhaled 100 or 300 ppm for 2 h absorbed total systemic doses of (10 or 30 mg/kg DCE, respectively. Other groups of rats received 10 or 30 mg/kg DCE by intravenous injection, bolus gavage (by mouth), or gastric infusion (g.i.) over a 2-h period. Serial microblood samples were taken from the cannulated, unanesthetized animals and analyzed for DCE content by gas chromatography to obtain concentration versus time profiles. Inhalation resulted in substantially higher peak blood concentrations and area under blood-concentration time curves (AUC 0 2 ) than did gastric infusion of the same dose over the same time frame at each dosage level, although inhalation (AUC 0 ϱ ) values were only modestly higher. Urinary N-acetyl-␤-D-glucosaminidase (NAG) and ␥-glutamyltranspeptidase (GGT) activities were monitored as indices of kidney injury in the high-dose groups. NAG and GGT excretion were much more pronounced after inhalation than gastric infusion. Administration of DCE by gavage also produced much higher C max and AUC 0 2 values than did 2-h g.i., although AUC 0 ϱ values were not very different. The 30 mg/kg bolus dose produced marked elevation in serum sorbitol dehydrogenase, an index of hepatocellular injury. Administration of this dose by inhalation and gastric infusion was only marginally hepatotoxic. These findings demonstrate the TK and target organ toxicity of DCE vary substantially between different exposure routes, as well as dosage regimens, making direct extrapolations untenable in health risk assessments.Home use of volatile organic chemical (VOC)-contaminated tap water commonly results in exposure by multiple routes. Previously, toxicity/carcinogenicity risk assessments focused primarily on the amount of chemical in the water ingested. It is now recognized that inhalation during showering and other water-use activities also contribute significantly to one's systemically absorbed dose (Weisel and Jo, 1996;Gordon et al., 2006). There is little information, however, on the relative quantities and toxicities of VOCs absorbed from different portals. Health risk assessments of ingested VOCs must often be conducted on the basis of inhalation toxicity data, with direct extrapolation from one route of exposure to another. In addition, oral cancer and noncancer studies of VOCs in rodents have usually used daily gavage dosing. The relevance of these single bolus data to human risks is questionable, as people typically consume contaminated water in small, divided doses over the course of the day.1,1-Dichloroethylene (DCE) was selected for the current study. It is used primarily as a chemical intermediate and in the production of polyvinylidene copolymers used to produce flexible films (e.g., Saranwrap, Velon) for food packaging. Environmental releases occur primarily by evaporation, although some DCE is released ...

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Tandem MS Analysis of Model Peptide Adducts from Reactive Metabolites of the Hepatotoxin 1,1-Dichloroethylene

Cited by 12 publications

References 17 publications

Proteomic Characterization of Metabolites, Protein Adducts, and Biliary Proteins in Rats Exposed to 1,1-Dichloroethylene or Diclofenac

Proteomic Characterization of Metabolites, Protein Adducts, and Biliary Proteins in Rats Exposed to 1,1-Dichloroethylene or Diclofenac

Analysis of naphthalene adduct binding sites in model proteins by tandem mass spectrometry

Influence of Exposure Route and Oral Dosage Regimen on 1, 1-Dichloroethylene Toxicokinetics and Target Organ Toxicity

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