201
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Affiliation(s)
- Lawrence M. Sayre
- Departments of Chemistry, Pathology, and Environmental Health Sciences, Case Western Reserve University, Cleveland, Ohio 44106, and College of Sciences, University of Texas at San Antonio, San Antonio, Texas 78249
| | - George Perry
- Departments of Chemistry, Pathology, and Environmental Health Sciences, Case Western Reserve University, Cleveland, Ohio 44106, and College of Sciences, University of Texas at San Antonio, San Antonio, Texas 78249
| | - Mark A. Smith
- Departments of Chemistry, Pathology, and Environmental Health Sciences, Case Western Reserve University, Cleveland, Ohio 44106, and College of Sciences, University of Texas at San Antonio, San Antonio, Texas 78249
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202
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Burcham PC, Raso A, Thompson C, Tan D. Intermolecular protein cross-linking during acrolein toxicity: efficacy of carbonyl scavengers as inhibitors of heat shock protein-90 cross-linking in A549 cells. Chem Res Toxicol 2007; 20:1629-37. [PMID: 17907782 DOI: 10.1021/tx700192e] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The smoke-borne electrophile acrolein reacts extensively with proteins, forming carbonyl-retaining Michael adducts that may be attacked by adjacent protein nucleophiles to form cross-links. Because little information is available concerning the extent of intermolecular protein cross-linking during acrolein toxicity in cells, we used an antibody against a known target for toxic carbonyls, the chaperone protein Hsp90, to detect the formation of high-mass protein complexes in acrolein-exposed A549 cells. A 3 h exposure to acrolein (0 to 200 microM) resulted in concentration-dependent formation of a single high-mass band (approx. 180 kDa). This species was detected in cells exposed to just 50 microM acrolein, a concentration that did not elicit acute cell death as assessed by measurements of cell ATP levels. The formation of cross-linked Hsp90 coincided with a rapid loss of carbonyl adducts within cells that had been subjected to a brief "pulse" exposure to a subtoxic concentration of acrolein, suggesting Michael adducts are short-lived within cells due in part to consumption during reactions with protein nucleophiles. Cross-linked Hsp90 persisted following an overnight recovery incubation, suggesting the cellular ability to repair or degrade these species is limited. Two known carbonyl scavengers, hydralazine and bisulfite, strongly protected against the ATP depletion accompanying acrolein exposure, but only the latter suppressed protein adduction and Hsp90 cross-linking. As previously shown for hydralazine, mass spectrometry studies using a model peptide indicated that bisulfite traps carbonyl groups possessed by Michael addition adducts, and such adduct-trapping reactivity appeared to contribute to the blockade of Hsp90 cross-linking in acrolein-preloaded cells. Collectively, these findings establish that formation of stable intermolecular protein cross-links accompanies exposure to acrolein. Future clarification of the chemistry underlying this damage may provide novel biomarkers of acrolein exposure.
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Affiliation(s)
- Philip C Burcham
- Pharmacology and Anaesthesiology Unit, School of Medicine & Pharmacology, The University of Western Australia, Crawley, WA 6009, Australia.
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203
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Druckova A, Mernaugh RL, Ham AJL, Marnett LJ. Identification of the Protein Targets of the Reactive Metabolite of Teucrin A in Vivo in the Rat. Chem Res Toxicol 2007; 20:1393-408. [PMID: 17892266 DOI: 10.1021/tx7001405] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Covalent modification of proteins is associated with the toxicity of many electrophiles, and the identification of relevant in vivo protein targets is a desirable but challenging goal. Here, we describe a strategy for the enrichment of adducted proteins utilizing single-chain fragment variable (ScFv) antibodies selected using phage-display technology. Teucrin A is a furan-containing diterpenoid found in the herb germander that is primarily responsible for the herb's hepatotoxicity in rodents and humans following metabolic activation by cytochrome P450 enzymes. Conjugates of the 1,4-enedial derivative of teucrin A, its presumed toxic metabolite, with lysine- and cysteine-containing peptides were synthesized and used to select ScFvs from a rodent phage-displayed library, which recognized the terpenoid moiety of the teucrin-derived adducts. Immunoaffinity isolation of adducted proteins from rat liver homogenates following administration of a toxic dose of teucrin A afforded a family of proteins that were identified by liquid chromatography/tandem mass spectrometry. Of the 46 proteins identified in this study, most were of mitochondrial and endoplasmic reticulum origin. Several cytosolic proteins were found, as well as four peroxisomal and two secreted proteins. Using Ingenuity Pathway Analysis software, two significant networks involving the target genes were identified that had major functions in gene expression, small molecule biochemistry, and cellular function and maintenance. These included proteins involved in lipid, amino acid, and drug metabolism. This study illustrates the utility of chemically synthesized biological conjugates of reactive intermediates and the potential of the phage display technology for the generation of affinity reagents for the isolation of adducted proteins.
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Affiliation(s)
- Alexandra Druckova
- Department of Biochemistry, A. B. Hancock Jr. Memorial Laboratory for Cancer Research, Vanderbilt Institute of Chemical Biology, Center in Molecular Toxicology, Vanderbilt University School of Medicine, Nashville, TN 37232-0146, USA
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204
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Girotti AW, Giacomoni PU. Lipid and Protein Damage Provoked by Ultraviolet Radiation: Mechanisms of Indirect Photooxidative Damage. BIOPHYSICAL AND PHYSIOLOGICAL EFFECTS OF SOLAR RADIATION ON HUMAN SKIN 2007. [DOI: 10.1039/9781847557957-00271] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Affiliation(s)
- Albert W. Girotti
- Department of Biochemistry Medical College of Wisconsin Milwaukee WI USA
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205
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Gorelik S, Ligumsky M, Kohen R, Kanner J. A novel function of red wine polyphenols in humans: prevention of absorption of cytotoxic lipid peroxidation products. FASEB J 2007; 22:41-6. [PMID: 17712060 DOI: 10.1096/fj.07-9041com] [Citation(s) in RCA: 132] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Current evidence supports a contribution of polyphenols to the prevention of cardiovascular disease, but their mechanisms of action are not understood. We investigated the impact of red wine polyphenols on postprandial cytotoxic lipid peroxidation products (MDA) levels in humans. In a randomized, crossover study, the effect of red wine polyphenols on postprandial levels of plasma and urine MDA was investigated. Three meals of 250 g turkey cutlets supplemented by water (A); soaked in red wine after heating plus 200 ml of red wine (B); or soaked in red wine prior to heating plus 200 ml of red wine (C) were administered to 10 healthy volunteers. Subject baseline plasma levels of MDA were 50 +/- 20 nM. After a meal of turkey meat cutlets, plasma MDA levels increased by 160 nM (P<0.0001); after (B) there was a 75% reduction in the absorption of MDA (P<0.0001). However, after (C), the elevation of plasma MDA was completely prevented (P<0.0001). Similar results were obtained for MDA accumulation in urine. Our study suggests that red wine polyphenols exert a beneficial effect by the novel new function, absorption inhibition of the lipotoxin MDA. These findings explain the potentially harmful effects of oxidized fats found in foods and the important benefit of dietary polyphenols in the meal.
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Affiliation(s)
- Shlomit Gorelik
- Department of Pharmaceutics, David R. Bloom Center of Pharmacy, School of Pharmacy, the Hebrew University of Jerusalem, Jerusalem, Israel
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206
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207
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Sigolo CAO, Di Mascio P, Medeiros MHG. Covalent modification of cytochrome c exposed to trans,trans-2,4-decadienal. Chem Res Toxicol 2007; 20:1099-110. [PMID: 17658762 DOI: 10.1021/tx700111v] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Modification of biomolecules by reactive aldehydes is believed to play a role in biological processes, including aging, atherosclerosis, and Alzheimer's disease. Here, the modification of cytochrome c promoted by trans, trans-2,4-decadienal (DDE) was investigated. Matrix-assisted laser desorption/ionization time-of-flight experiments indicated increases in the molecular weight of cytochrome c, consistent with the formation of DDE adducts. Our data show that the protein modification was time-, pH-, and DDE concentration-dependent, leading to the formation of at least six adducts after 2 h of incubation at pH 7.4. Electrospray ionization quantitative TOF mass spectrometry analysis of tryptic digests indicated that His-33, Lys-39, Lys-72, and Lys-100 were modified by DDE. These adducts could have significant effects considering that His-33, Lys-72, and Lys-100 are present in clusters of basic amino acid residues, which are believed to participate in the interaction of cytochrome c with cardiolipin in the inner mitochondrial membrane and cytochrome c oxidase. A blue shift in the cytochrome c Soret band from 409 to 406 nm was also observed after DDE reaction, indicating heme crevice opening and displacement of heme sixth ligand (Met-80) coordination in modified protein. The covalent modifications in cytochrome c could play a role in mitochondrial dysfunction associated with oxidative stress.
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Affiliation(s)
- Carlos A O Sigolo
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, Av. Prof. Lineu Prestes 748, CEP 05508-900, São Paulo, Brazil
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208
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Iyanagi T. Molecular mechanism of phase I and phase II drug-metabolizing enzymes: implications for detoxification. ACTA ACUST UNITED AC 2007; 260:35-112. [PMID: 17482904 DOI: 10.1016/s0074-7696(06)60002-8] [Citation(s) in RCA: 154] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Enzymes that catalyze the biotransformation of drugs and xenobiotics are generally referred to as drug-metabolizing enzymes (DMEs). DMEs can be classified into two main groups: oxidative or conjugative. The NADPH-cytochrome P450 reductase (P450R)/cytochrome P450 (P450) electron transfer systems are oxidative enzymes that mediate phase I reactions, whereas the UDP-glucuronosyltransferases (UGTs) are conjugative enzymes that mediate phase II enzymes. Both enzyme systems are localized to the endoplasmic reticulum (ER) where a number of drugs are sequentially metabolized. DMEs, including P450s and UGTs, generally have a highly plastic active site that can accommodate a wide variety of substrates. The P450 and UGT genes constitute a supergene family, in which UGT proteins are encoded by distinct genes and a complex gene. Both the P450 and UGT genes have evolved to diversify their functions. This chapter reviews advances in understanding the structure and function of the P450R/P450 and UGT enzyme systems. In particular, the coordinate biotransformation of xenobiotics by phase I and II enzymes in the ER membrane is examined.
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Affiliation(s)
- Takashi Iyanagi
- Biometal Science Laboratory, RIKEN SPring-8 Center, Harima Institute, Hyogo 679-5148, Japan
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209
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Sturla SJ. DNA adduct profiles: chemical approaches to addressing the biological impact of DNA damage from small molecules. Curr Opin Chem Biol 2007; 11:293-9. [PMID: 17574899 DOI: 10.1016/j.cbpa.2007.05.021] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2007] [Accepted: 05/29/2007] [Indexed: 10/23/2022]
Abstract
Diverse small molecules alkylate DNA and form covalently linked adducts that can influence crucial biological processes, contributing to toxicity and mutation. Understanding the chemical reactivity dictating DNA alkylation and interactions of adducts with biological pathways can impact disease prevention and treatment. The ambident reactivity of DNA-alkylating small molecules, and of DNA itself, often results in formation of multiple adducts. Determining which structures impart biological responses is important for understanding the underlying relationships between small-molecule structure and biology. With application of sensitive and structure-specific experimental and analytical methodology, such as heteronuclear NMR spectroscopy and mass spectrometry, there are increasing numbers of studies that evaluate DNA alkylation from the perspective of resulting adduct profiles. DNA adduct profiles have been examined for both exogenous and endogenous reactive small molecules. Examples of recent findings are in the areas of tobacco-specific carcinogens, lipid peroxidation products, environmental and dietary chlorophenols, and natural-product-derived antitumor therapies. As more profile data are obtained, correlations with biological impact are being observed that would not be identified by a simplified single agent/single adduct approach.
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Affiliation(s)
- Shana J Sturla
- Department of Medicinal Chemistry and The Cancer Center, University of Minnesota, 308 Harvard Street SE, Minneapolis, MN 55455, USA.
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210
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Orton CR, Liebler DC. Analysis of protein adduction kinetics by quantitative mass spectrometry: competing adduction reactions of glutathione-S-transferase P1-1 with electrophiles. Chem Biol Interact 2007; 168:117-27. [PMID: 17433278 PMCID: PMC2063493 DOI: 10.1016/j.cbi.2007.03.005] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2006] [Revised: 03/09/2007] [Accepted: 03/12/2007] [Indexed: 11/24/2022]
Abstract
Defining the mechanisms and consequences of protein adduction is crucial to understanding the toxicity of reactive electrophiles. Application of tandem mass spectrometry and data analysis algorithms enables detection and mapping of chemical adducts at the level of amino acid sequence. Nevertheless, detection of adducts does not indicate relative reactivity of different sites. Here, we describe a method to measure the kinetics of competing adduction reactions at different sites on the same protein. Adducts are formed by electrophiles at Cys14 and Cys47 on the metabolic enzyme glutathione-S-transferase P1-1 and modification is accompanied by a loss of enzymatic activity. Relative quantitation of protein adducts was done by tagging N-termini of peptide digests with isotopically labeled phenyl isocyanate and tracking the ratio of light-tagged peptide adducts to heavy-tagged reference samples in liquid chromatography-tandem mass spectrometry analyses using a multiple reaction monitoring method. This approach was used to measure rate constants for adduction at both positions with two different model electrophiles, N-iodoacetyl-N-biotinylhexylenediamine and 1-biotinamido-4-(4'-[maleimidoethyl-cyclohexane]-carboxamido)butane. The results indicate that Cys47 was approximately two- to three-fold more reactive toward both electrophiles than was Cys14. This result was consistent with the relative reactivity of these electrophiles in a complex proteome system and with previously reported trends in reactivity of these sites. Kinetic analyses of protein modification reactions provide a means of evaluating the selectivity of reactive mediators of chemical toxicity.
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Affiliation(s)
- Christopher R. Orton
- Department of Pharmacology and Toxicology, College of Pharmacy, The University of Arizona, Tucson, AZ
| | - Daniel C. Liebler
- Departments of Biochemistry and Pharmacology and Mass Spectrometry Research Center, Vanderbilt University School of Medicine, Nashville, TN
- *Author to whom correspondence should be addressed at: Department of Biochemistry, Vanderbilt University School of Medicine, Rm. 9110A Medical, Research Building III, 465 21 Avenue South, Nashville, TN 37232-8575, Phone 615 322-3063, FAX 615 343-8372
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211
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Köhle C, Bock KW. Coordinate regulation of Phase I and II xenobiotic metabolisms by the Ah receptor and Nrf2. Biochem Pharmacol 2007; 73:1853-62. [PMID: 17266942 DOI: 10.1016/j.bcp.2007.01.009] [Citation(s) in RCA: 261] [Impact Index Per Article: 15.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2006] [Revised: 12/21/2006] [Accepted: 01/03/2007] [Indexed: 11/21/2022]
Abstract
The aryl hydrocarbon receptor (AhR) is a ligand-activated transcription factor with important roles in metabolic adaptation, normal physiology and dioxin toxicology. Metabolic adaptation is based on coordinate regulation of a set of xenobiotic-metabolizing enzymes (XMEs), termed AhR battery. Coordination is achieved by AhR/Arnt-binding to XREs (xenobiotic response elements), identified in the 5' upstream region of AhR target genes. The AhR battery encodes Phase I and II enzymes. Interestingly, these Phase II genes are linked to the Nrf2 gene battery that encodes enzymes that are essential in protection against oxidative/electrophile stress. Nrf2 binds to AREs (antioxidant response elements) in the regulatory region of a large and distinct set of target genes. Functionally characterized response elements such as XREs and AREs in the regulatory region of target genes may provide a genetic basis to understand AhR- and Nrf2-induced genes. Linkage between AhR and Nrf2 batteries is probably achieved by multiple mechanisms, including Nrf2 as a target gene of the AhR, indirect activation of Nrf2 via CYP1A1-generated reactive oxygen species, and direct cross-interaction of AhR/XRE and Nrf2/ARE signaling. Linkage appears to be species- and cell-dependent. However, mechanisms linking XRE- and ARE-controlled Phase II genes need further investigation. Tightened coupling between Phases I and II by AhR- and Nrf2-induced XMEs may greatly attenuate health risks posed by CYP1A1-generated toxic intermediates and reactive oxygen species. Better recognition of coordinate Phase I and II metabolisms may improve risk assessment of reactive toxic intermediates in the extrapolation to low level endo- and xenobiotic exposure.
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Affiliation(s)
- Christoph Köhle
- Department of Toxicology, Institute of Pharmacology and Toxicology, University of Tübingen, Germany
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212
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Bartsch H, Nair J. Chronic inflammation and oxidative stress in the genesis and perpetuation of cancer: role of lipid peroxidation, DNA damage, and repair. Langenbecks Arch Surg 2006; 391:499-510. [PMID: 16909291 DOI: 10.1007/s00423-006-0073-1] [Citation(s) in RCA: 328] [Impact Index Per Article: 18.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2006] [Accepted: 05/12/2006] [Indexed: 02/07/2023]
Abstract
BACKGROUND AND AIMS Chronic inflammation, induced by biological, chemical, and physical factors, was associated with increased risk of human cancer at various sites. Chronic inflammatory processes induce oxidative/nitrosative stress and lipid peroxidation (LPO), thereby generating excess reactive oxygen species (ROS), reactive nitrogen species (RNS), and DNA-reactive aldehydes. Miscoding etheno- and propano-modified DNA bases are generated inter alia by reaction of DNA with these major LPO products. Steady-state levels of LPO-derived (etheno-) DNA adducts in organs affected by persistent inflammatory processes were investigated as potential lead markers for assessing progression of inflammatory cancer-prone diseases. RESULTS Using ultrasensitive and specific detection methods for the analysis of human tissues, cells, and urine, etheno-DNA adduct levels were found to be significantly elevated in the affected organs of subjects with chronic pancreatitis, ulcerative colitis, and Crohn's disease. Patients with alcohol-related liver diseases showed excess hepatic DNA damage progressively increasing from hepatitis, fatty liver, to liver cirrhosis. Ethenodeoxyadenosine excreted after DNA repair in urine of hepatitis B virus-related chronic hepatitis and liver cirrhosis patients was increased up to 90-fold. Putative mechanisms that may control DNA damage in inflamed tissues including impaired or imbalanced DNA repair pathways are reviewed. CONCLUSION Persistent oxidative/nitrosative stress and excess LPO are induced by inflammatory processes in a self-perpetuating process and cause progressive accumulation of DNA damage in target organs. Together with deregulation of cell homeostasis, the resulting genetic changes act as driving force in chronic inflammation-associated human disease pathogenesis. Thus steady-state levels of DNA damage caused by ROS, RNS, and LPO end products provide promising molecular signatures for risk prediction and potential targets and biomarkers for preventive measures.
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Affiliation(s)
- Helmut Bartsch
- Division of Toxicology and Cancer Risk Factors, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120 Heidelberg, Germany.
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