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Hansruedi Glatt - One of the best experts on this subject based on the ideXlab platform.
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Strong impact of sulfotransferases on DNA adduct formation by 4-aminobiphenyl in bladder and liver in mice.
Cancer medicine, 2018Co-Authors: Zhidan Chen, Walter Meinl, Hansruedi Glatt, Joseph D. Paonessa, Arup Bhattacharya, Paul Vouros, Yuesheng ZhangAbstract:Bladder cancer risk is 3-4 times higher in men than women, but the reason is poorly understood. In mice, male bladder is also more susceptible than female bladder to 4-aminobiphenyl (ABP), a major human bladder carcinogen; however, female liver is more susceptible than male liver to ABP. We investigated the role of sulfotransferase (Sult) in gender-related bladder and liver susceptibility to ABP. Sulfation reactions of aromatic amine bladder carcinogens catalyzed by Sult may generate highly unstable and toxic metabolites. Therefore, liver Sult may decrease bladder exposure to carcinogens by promoting their toxic reactions in the liver. Notably, the expression of several liver Sults is suppressed by androgen in male mice. Here, we show that two Sults are critical for gender-related bladder susceptibility to ABP in mice. We measured tissue level of N-(deoxyguanosin-8-yl)-4-aminobiphenyl (dG-C8-ABP), a principal ABP-DNA adduct, as readout of tissue susceptibility to ABP. We identified Sutl1a1 and to a lesser extent Sult1d1 as Sults that promote dG-C8-ABP formation in hepatic cells. In mice, gender gap in bladder susceptibility to ABP was narrowed by knocking out SULT1A1 and was almost totally eliminated by knocking out both Sutl1a1 and Sult1d1. This was accompanied by dramatic decrease in ABP genotoxicity in the liver (>97%). These results show the strong impact of the Sults on bladder and liver susceptibility to a human carcinogen. Because liver expression of both SULT1A1 and Sutl1d1 is suppressed by androgen in male mice, our results suggest that androgen renders bladder more exposed to ABP in male mice by suppressing Sult-mediated ABP metabolism in liver, which increases bladder delivery of carcinogenic metabolites.
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role of exposure recovery schedule in micronuclei induction by several promutagens in v79 derived cells expressing human cyp2e1 and SULT1A1
Mutation Research-genetic Toxicology and Environmental Mutagenesis, 2016Co-Authors: Hansi Jia, Chiteng Zhang, Hansruedi Glatt, Yungang LiuAbstract:The standard procedure for the micronucleus test in cell lines requires a short exposure (≤0.5 cell cycle) to the test compounds followed by a long recovery (≥1.5 cell cycle), and in case of negative or equivocal results, a second test with extended exposure (≥2 cell cycles) without or with a recovery time. In general the two procedures are advantageous for detecting clastogens and aneugens, respectively. However, whether the recommended procedures apply to micronucleus tests with promutagens in cell lines genetically engineered for expressing biotransformation enzymes has not been identified. In this study, several promutagens dependent on cytochrome P450 (CYP) 2E1 and/or sulfotransferase (SULT) 1A1 were used in the micronucleus test in a Chinese hamster V79-derived cell line expressing human CYP2E1 and SULT1A1 (V79-hCYP2E1-hSULT1A1), with varying exposure/recovery schedules: 3h/21h, 6h/18h, 12h/12h, 18h/6h, and 24h/0h, in comparison with known clastogens and aneugens in V79 control cells. The results showed peaked micronuclei induction by mitomycin C and bleomycin (clastogens) at the 12h/12h schedule, while colchicine and vinblastine (aneugens) showed the strongest effect at 24h/0h. Catechol and trihydroxybenzene (activated by CYP2E1) induced micronuclei most strongly at 6h/18h, whereas somewhat longer exposures were optimal for hydroquinone, another compound activated by CYP2E1. 1-Hydroxymethylpyrene (activated by SULT1A1) and 1-methylpyrene (activated sequentially by CYP2E1 and SULT1A1) produced the highest response with the 18h/6h treatment regimen. Moreover, mitotic arrest by 1-hydroxymethylpyrene was observed in V79-hCYP2E1-hSULT1A1 cells but not in V79 cells, and 1-methylpyrene arrested mitosis in V79-hCYP2E1-hSULT1A1 more strongly than in V79 cells. Our study suggests that intracellular bioactivation of promutagens may not delay the induction of micronuclei in the present model, and 1-methylpyrene and 1-hydroxymethylpyrene may be activated to mitosis-arresting metabolites.
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Role of exposure/recovery schedule in micronuclei induction by several promutagens in V79-derived cells expressing human CYP2E1 and SULT1A1
Mutation Research-genetic Toxicology and Environmental Mutagenesis, 2016Co-Authors: Chiteng Zhang, Hansruedi GlattAbstract:Abstract The standard procedure for the micronucleus test in cell lines requires a short exposure (≤0.5 cell cycle) to the test compounds followed by a long recovery (≥1.5 cell cycle), and in case of negative or equivocal results, a second test with extended exposure (≥2 cell cycles) without or with a recovery time. In general the two procedures are advantageous for detecting clastogens and aneugens, respectively. However, whether the recommended procedures apply to micronucleus tests with promutagens in cell lines genetically engineered for expressing biotransformation enzymes has not been identified. In this study, several promutagens dependent on cytochrome P450 (CYP) 2E1 and/or sulfotransferase (SULT) 1A1 were used in the micronucleus test in a Chinese hamster V79-derived cell line expressing human CYP2E1 and SULT1A1 (V79-hCYP2E1-hSULT1A1), with varying exposure/recovery schedules: 3 h/21 h, 6 h/18 h, 12 h/12 h, 18 h/6 h, and 24 h/0 h, in comparison with known clastogens and aneugens in V79 control cells. The results showed peaked micronuclei induction by mitomycin C and bleomycin (clastogens) at the 12 h/12 h schedule, while colchicine and vinblastine (aneugens) showed the strongest effect at 24 h/0 h. Catechol and trihydroxybenzene (activated by CYP2E1) induced micronuclei most strongly at 6 h/18 h, whereas somewhat longer exposures were optimal for hydroquinone, another compound activated by CYP2E1. 1-Hydroxymethylpyrene (activated by SULT1A1) and 1-methylpyrene (activated sequentially by CYP2E1 and SULT1A1) produced the highest response with the 18 h/6 h treatment regimen. Moreover, mitotic arrest by 1-hydroxymethylpyrene was observed in V79-hCYP2E1-hSULT1A1 cells but not in V79 cells, and 1-methylpyrene arrested mitosis in V79-hCYP2E1-hSULT1A1 more strongly than in V79 cells. Our study suggests that intracellular bioactivation of promutagens may not delay the induction of micronuclei in the present model, and 1-methylpyrene and 1-hydroxymethylpyrene may be activated to mitosis-arresting metabolites.
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Bioactivation of food genotoxicants 5-hydroxymethylfurfural and furfuryl alcohol by sulfotransferases from human, mouse and rat: a comparative study
Archives of Toxicology, 2016Co-Authors: Benjamin Sachse, Walter Meinl, Hansruedi Glatt, Yasmin Sommer, Albrecht Seidel, Bernhard H MonienAbstract:5-Hydroxymethylfurfural (HMF) and furfuryl alcohol (FFA) are moderately potent rodent carcinogens that are present in thermally processed foodstuffs. The carcinogenic effects were hypothesized to originate from sulfotransferase (SULT)-mediated bioactivation yielding DNA-reactive and mutagenic sulfate esters, a confirmed metabolic pathway of HMF and FFA in mice. It is known that orthologous SULT forms substantially differ in substrate specificity and tissue distribution. This could influence HMF- and FFA-induced carcinogenic effects. Here, we studied HMF and FFA sulfoconjugation by 30 individual SULT forms of humans, mice and rats. The catalytic efficiencies ( k _cat/ K _M) of HMF sulfoconjugation of human SULT1A1 (13.7 s^−1 M^−1), mouse SULT1A1 (15.8 s^−1 M^−1) and 1d1 (4.8 s^−1 M^−1) and rat SULT1A1 (5.3 s^−1 M^−1) were considerably higher than those of all other SULT forms investigated (≤0.73 s^−1 M^−1). FFA sulfoconjugation was monitored using adenosine as a nucleophilic scavenger for the reactive 2-sulfoxymethylfuran ( t _1/2 = 20 s at 37 °C). The resulting adduct N ^6-((furan-2-yl)methyl)-adenosine ( N ^6-MF-A) was quantified by isotope-dilution UPLC-MS/MS. The rates of N ^6-MF-A formation showed that hSULT1A1 and its orthologues in mice and rats were also the most important contributors to FFA sulfoconjugation in each of the species. Taken together, the catalytic capacity of hSULT1A1 is comparable to that of mSULT1A1 in mice, the species in which carcinogenic effects of HMF and FFA were detected. This is of primary concern due to the expression of hSULT1A1 in many different tissues.
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the effect of knockout of sulfotransferases 1a1 and 1d1 and of transgenic human sulfotransferases 1a1 1a2 on the formation of dna adducts from furfuryl alcohol in mouse models
Carcinogenesis, 2014Co-Authors: Benjamin Sachse, Walter Meinl, Hansruedi Glatt, Bernhard H MonienAbstract:Furfuryl alcohol is a rodent carcinogen present in numerous foodstuffs. Sulfotransferases (SULTs) convert furfuryl alcohol into the DNA reactive and mutagenic 2-sulfoxymethylfuran. Sensitive techniques for the isotope-dilution ultra performance liquid chromatography-tandem mass spectrometry quantification of resulting DNA adducts, e.g. N (2)-((furan-2-yl)methyl)-2'-deoxyguanosine (N (2)-MF-dG), were developed. To better understand the contribution of specific SULT forms to the genotoxicity of furfuryl alcohol in vivo, we studied the tissue distribution of N (2)-MF-dG in different mouse models. Earlier mutagenicity studies with Salmonella typhimurium strains expressing different human and murine SULT forms indicated that human SULT1A1 and murine SULT1A1 and 1d1 catalyze furfuryl alcohol sulfo conjugation most effectively. Here, we used three mouse lines to study the bioactivation of furfuryl alcohol by murine SULTs, FVB/N wild-type (wt) mice and two genetically modified models lacking either murine SULT1A1 or Sult1d1. The animals received a single dose of furfuryl alcohol, and the levels of the DNA adducts were determined in liver, kidney, lung, colon and small intestine. The effect of Sult1d1 gene disruption on the genotoxicity of furfuryl alcohol was moderate and limited to kidney and small intestine. In contrast, the absence of functional SULT1A1 had a massive influence on the adduct levels, which were lowered by 33-73% in all tissues of the female SULT1A1 null mice compared with the wt animals. The detection of high N (2)-MF-dG levels in a humanized mouse line expressing hSULT1A1/1A2 instead of endogeneous SULT1A1 and Sult1d1 supports the hypothesis that furfuryl alcohol is converted to the mutagenic 2-sulfoxymethylfuran also in humans.
Walter Meinl - One of the best experts on this subject based on the ideXlab platform.
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Strong impact of sulfotransferases on DNA adduct formation by 4-aminobiphenyl in bladder and liver in mice.
Cancer medicine, 2018Co-Authors: Zhidan Chen, Walter Meinl, Hansruedi Glatt, Joseph D. Paonessa, Arup Bhattacharya, Paul Vouros, Yuesheng ZhangAbstract:Bladder cancer risk is 3-4 times higher in men than women, but the reason is poorly understood. In mice, male bladder is also more susceptible than female bladder to 4-aminobiphenyl (ABP), a major human bladder carcinogen; however, female liver is more susceptible than male liver to ABP. We investigated the role of sulfotransferase (Sult) in gender-related bladder and liver susceptibility to ABP. Sulfation reactions of aromatic amine bladder carcinogens catalyzed by Sult may generate highly unstable and toxic metabolites. Therefore, liver Sult may decrease bladder exposure to carcinogens by promoting their toxic reactions in the liver. Notably, the expression of several liver Sults is suppressed by androgen in male mice. Here, we show that two Sults are critical for gender-related bladder susceptibility to ABP in mice. We measured tissue level of N-(deoxyguanosin-8-yl)-4-aminobiphenyl (dG-C8-ABP), a principal ABP-DNA adduct, as readout of tissue susceptibility to ABP. We identified Sutl1a1 and to a lesser extent Sult1d1 as Sults that promote dG-C8-ABP formation in hepatic cells. In mice, gender gap in bladder susceptibility to ABP was narrowed by knocking out SULT1A1 and was almost totally eliminated by knocking out both Sutl1a1 and Sult1d1. This was accompanied by dramatic decrease in ABP genotoxicity in the liver (>97%). These results show the strong impact of the Sults on bladder and liver susceptibility to a human carcinogen. Because liver expression of both SULT1A1 and Sutl1d1 is suppressed by androgen in male mice, our results suggest that androgen renders bladder more exposed to ABP in male mice by suppressing Sult-mediated ABP metabolism in liver, which increases bladder delivery of carcinogenic metabolites.
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Bioactivation of food genotoxicants 5-hydroxymethylfurfural and furfuryl alcohol by sulfotransferases from human, mouse and rat: a comparative study
Archives of Toxicology, 2016Co-Authors: Benjamin Sachse, Walter Meinl, Hansruedi Glatt, Yasmin Sommer, Albrecht Seidel, Bernhard H MonienAbstract:5-Hydroxymethylfurfural (HMF) and furfuryl alcohol (FFA) are moderately potent rodent carcinogens that are present in thermally processed foodstuffs. The carcinogenic effects were hypothesized to originate from sulfotransferase (SULT)-mediated bioactivation yielding DNA-reactive and mutagenic sulfate esters, a confirmed metabolic pathway of HMF and FFA in mice. It is known that orthologous SULT forms substantially differ in substrate specificity and tissue distribution. This could influence HMF- and FFA-induced carcinogenic effects. Here, we studied HMF and FFA sulfoconjugation by 30 individual SULT forms of humans, mice and rats. The catalytic efficiencies ( k _cat/ K _M) of HMF sulfoconjugation of human SULT1A1 (13.7 s^−1 M^−1), mouse SULT1A1 (15.8 s^−1 M^−1) and 1d1 (4.8 s^−1 M^−1) and rat SULT1A1 (5.3 s^−1 M^−1) were considerably higher than those of all other SULT forms investigated (≤0.73 s^−1 M^−1). FFA sulfoconjugation was monitored using adenosine as a nucleophilic scavenger for the reactive 2-sulfoxymethylfuran ( t _1/2 = 20 s at 37 °C). The resulting adduct N ^6-((furan-2-yl)methyl)-adenosine ( N ^6-MF-A) was quantified by isotope-dilution UPLC-MS/MS. The rates of N ^6-MF-A formation showed that hSULT1A1 and its orthologues in mice and rats were also the most important contributors to FFA sulfoconjugation in each of the species. Taken together, the catalytic capacity of hSULT1A1 is comparable to that of mSULT1A1 in mice, the species in which carcinogenic effects of HMF and FFA were detected. This is of primary concern due to the expression of hSULT1A1 in many different tissues.
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the effect of knockout of sulfotransferases 1a1 and 1d1 and of transgenic human sulfotransferases 1a1 1a2 on the formation of dna adducts from furfuryl alcohol in mouse models
Carcinogenesis, 2014Co-Authors: Benjamin Sachse, Walter Meinl, Hansruedi Glatt, Bernhard H MonienAbstract:Furfuryl alcohol is a rodent carcinogen present in numerous foodstuffs. Sulfotransferases (SULTs) convert furfuryl alcohol into the DNA reactive and mutagenic 2-sulfoxymethylfuran. Sensitive techniques for the isotope-dilution ultra performance liquid chromatography-tandem mass spectrometry quantification of resulting DNA adducts, e.g. N (2)-((furan-2-yl)methyl)-2'-deoxyguanosine (N (2)-MF-dG), were developed. To better understand the contribution of specific SULT forms to the genotoxicity of furfuryl alcohol in vivo, we studied the tissue distribution of N (2)-MF-dG in different mouse models. Earlier mutagenicity studies with Salmonella typhimurium strains expressing different human and murine SULT forms indicated that human SULT1A1 and murine SULT1A1 and 1d1 catalyze furfuryl alcohol sulfo conjugation most effectively. Here, we used three mouse lines to study the bioactivation of furfuryl alcohol by murine SULTs, FVB/N wild-type (wt) mice and two genetically modified models lacking either murine SULT1A1 or Sult1d1. The animals received a single dose of furfuryl alcohol, and the levels of the DNA adducts were determined in liver, kidney, lung, colon and small intestine. The effect of Sult1d1 gene disruption on the genotoxicity of furfuryl alcohol was moderate and limited to kidney and small intestine. In contrast, the absence of functional SULT1A1 had a massive influence on the adduct levels, which were lowered by 33-73% in all tissues of the female SULT1A1 null mice compared with the wt animals. The detection of high N (2)-MF-dG levels in a humanized mouse line expressing hSULT1A1/1A2 instead of endogeneous SULT1A1 and Sult1d1 supports the hypothesis that furfuryl alcohol is converted to the mutagenic 2-sulfoxymethylfuran also in humans.
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highly selective bioactivation of 1 and 2 hydroxy 3 methylcholanthrene to mutagens by individual human and other mammalian sulphotransferases expressed in salmonella typhimurium
Mutagenesis, 2013Co-Authors: Walter Meinl, C N Falany, Carrie Tsoi, Stellan Swedmark, Zachary E Tibbs, Hansruedi GlattAbstract:The benzylic alcohols 1- and 2-hydroxy-3-methylcholanthrene (OH-MC) are major primary metabolites of the carcinogen 3-methylcholanthrene (MC). We investigated them for mutagenicity in TA1538-derived Salmonella typhimurium strains expressing mammalian sulphotransferases (SULTs). 1-OH-MC was efficiently activated by human (h) SULT1B1 (2400 revertants/nmol), weakly activated by hSULT1C3 and hSULT2A1 (2-9 revertants/nmol), but not activated by the other hSULTs studied (1A2, 1A3, 1C2 and 1E1). Mouse, rat and dog SULT1B1 activated 1-OH-MC (8-100 revertants/nmol) with much lower efficiency than their human orthologue. The other isomer, 2-OH-MC, was activated to a potent mutagen by hSULT1A1 (4000-5400 revertants/nmol), weakly activated by hSULT1A2 or hSULT2A1 (1-12 revertants/nmol), but not activated by the other hSULTs. In contrast to their human orthologue, mouse, rat and dog SULT1A1 did not appreciably activate 2-OH-MC (<1 to 6 revertants/nmol), either. Instead, mouse and rat SULT1B1, unlike their human and canine orthologues, demonstrated some activation of 2-OH-MC (15-100 revertants/nmol). Docking analyses indicated that 1- and 2-OH-MC might bind to the active site of hSULT1A1 and hSULT1B1, but only for (S)-2-OH-MC/hSULT1A1 and (R)-1-OH-MC/hSULT1B1 with an orientation suitable for catalysis. Indeed, 1- and 2-OH-MC were potent inhibitors of the hSULT1A1-mediated sulphation of acetaminophen [concentration inhibiting the enzyme activity by 50% (IC50) 15 and 13nM, respectively]. This inhibition was weak with mouse, rat and dog SULT1A1 (IC50 ≥ 4 µM). Inhibition of the SULT1B1 enzymes was moderate, strongest for 1-OH-MC/hSULT1B1. In conclusion, this study provides examples for high selectivity of bioactivation of promutagens by an individual form of human SULT and for pronounced differences in activation capacity between orthologous SULTs from different mammalian species. These characteristics make the detection and evaluation of such mutagens extremely difficult, in particular as the critical form may even differ for positional isomers, such as 1- and 2-OH-MC. Moreover, the species-dependent differences will complicate the verification of in vitro results in animal studies.
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The Journal of Clinical Endocrinology & Metabolism Printed in U.S.A. Copyright © 1999 by The Endocrine Society Characterization of Human Iodothyronine Sulfotransferases*
2013Co-Authors: Monique H. A. Kester, Ellen Kaptein, Michael W H Coughtrie, Walter Meinl, Hansruedi Glatt, Thirza J. Roest, Caren H. Van Dijk, Dick Tibboel, J. VisserAbstract:Sulfation is an important pathway of thyroid hormone metabolism that facilitates the degradation of the hormone by the type I iodothyronine deiodinase, but little is known about which human sulfotransferase isoenzymes are involved. We have investigated the sulfation of the prohormone T 4, the active hormone T 3, and the metabolites rT 3 and 3,3�-diiodothyronine (3,3�-T 2) by human liver and kidney cytosol as well as by recombinant human SULT1A1 and SULT1A3, previously known as phenol-preferring and monoaminepreferring phenol sulfotransferase, respectively. In all cases, the substrate preference was 3,3�-T 2 � � rT 3 � T 3 � T 4. The apparent K m values of 3,3�-T 2 and T 3 [at 50 �mol/L 3�-phosphoadenosine-5�-phosphosulfate (PAPS)] were 1.02 and 54.9 �mol/L for liver cytosol, 0.64 and 27.8 �mol/L for kidney cytosol, 0.14 and 29.1 �mol/L for SULT1A1, and 33 and 112 �mol/L for SULT1A3, respectively. Th
Michael W H Coughtrie - One of the best experts on this subject based on the ideXlab platform.
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The Journal of Clinical Endocrinology & Metabolism Printed in U.S.A. Copyright © 1999 by The Endocrine Society Characterization of Human Iodothyronine Sulfotransferases*
2013Co-Authors: Monique H. A. Kester, Ellen Kaptein, Michael W H Coughtrie, Walter Meinl, Hansruedi Glatt, Thirza J. Roest, Caren H. Van Dijk, Dick Tibboel, J. VisserAbstract:Sulfation is an important pathway of thyroid hormone metabolism that facilitates the degradation of the hormone by the type I iodothyronine deiodinase, but little is known about which human sulfotransferase isoenzymes are involved. We have investigated the sulfation of the prohormone T 4, the active hormone T 3, and the metabolites rT 3 and 3,3�-diiodothyronine (3,3�-T 2) by human liver and kidney cytosol as well as by recombinant human SULT1A1 and SULT1A3, previously known as phenol-preferring and monoaminepreferring phenol sulfotransferase, respectively. In all cases, the substrate preference was 3,3�-T 2 � � rT 3 � T 3 � T 4. The apparent K m values of 3,3�-T 2 and T 3 [at 50 �mol/L 3�-phosphoadenosine-5�-phosphosulfate (PAPS)] were 1.02 and 54.9 �mol/L for liver cytosol, 0.64 and 27.8 �mol/L for kidney cytosol, 0.14 and 29.1 �mol/L for SULT1A1, and 33 and 112 �mol/L for SULT1A3, respectively. Th
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quantitative evaluation of the expression and activity of five major sulfotransferases sults in human tissues the sult pie
Drug Metabolism and Disposition, 2009Co-Authors: Zoe Riches, Emma L Stanley, Jackie C Bloomer, Michael W H CoughtrieAbstract:Expression levels of the major human sulfotransferases (SULTs) involved in xenobiotic detoxification in a range of human tissues (i.e., SULT “pies”) are not available in a form allowing comparison between tissues and individuals. Here we have determined, by quantitative immunoblotting, expression levels for the five principal human SULTs—SULT1A1, SULT1A3/4, SULT1B1, SULT1E1, and SULT2A1—and determined the kinetic properties toward probe substrates, where available, for these enzymes in cytosol samples from a bank of adult human liver, small intestine, kidney, and lung. We produced new isoform-selective antibodies against SULT1B1 and SULT2A1, which were used alongside antibodies against SULT1A3 and SULT1A1 previously produced in our laboratory or available commercially (SULT1E1). Expression levels were derived using purified recombinant enzymes to construct standard curves for each individual isoform and immunoblot. Substantial intertissue and interindividual differences in expression were observed. SULT1A1 was the major enzyme (>50% of total, range 420-4900 ng/mg cytosol protein) in the liver, followed by SULT2A1, SULT1B1, and SULT1E1. SULT1A3 was completely absent from this tissue. In contrast, the small intestine contained the largest overall amount of SULT of any of the tissues, with SULT1B1 the major enzyme (36%), closely followed by SULT1A3 (31%), and SULT1A1, SULT1E1, and SULT2A1 more minor forms (19, 8, and 6% of total, respectively). The kidney and lung contained low levels of SULT. We provide a unique data set that will add value to the study of the role and contribution of sulfation to drug and xenobiotic metabolism in humans.
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Comparison of 2-aminophenol and 4-nitrophenol as in vitro probe substrates for the major human hepatic sulfotransferase, SULT1A1, demonstrates improved selectivity with 2-aminophenol.
Biochemical pharmacology, 2007Co-Authors: Zoe Riches, Jackie C Bloomer, Michael W H CoughtrieAbstract:Abstract Sulfation, catalysed by members of the cytosolic sulfotransferase (SULT) enzyme family, is important in xenobiotic detoxification and in the biosynthesis and homeostasis of many hormones and neurotransmitters. The major human phenol sulfotransferase SULT1A1 plays a key role in chemical defence, is widely expressed in the body and is subject to a common polymorphism that results in reduced protein levels. Study of these enzymes in vitro requires robust probe substrates, and we have previously shown measurement of activity with the widely used SULT1A1 substrate, 4-nitrophenol, does not accurately reflect protein expression. Additionally, the high degree of substrate inhibition observed with this compound further reduces its value as a probe for SULT1A1. Here we show that 2-aminophenol is a more suitable probe substrate for quantifying SULT1A1 activity in human liver. This compound is sulfated at a high rate ( V max with purified recombinant SULT1A1 = 121 nmol/(min mg) and shows strong affinity for the enzyme ( K m with purified recombinant SULT1A1 = 9 μM) and, importantly, is a very poor substrate for the other major SULT1 enzyme expressed in liver, SULT1B1 (with V max and K m values of 17 nmol/(min mg) and 114 μM, respectively). Experiments with purified recombinant human SULTs and a panel of 28 human liver cytosols demonstrated that 2-aminophenol shows limited substrate inhibition with SULT1A1, and V max values measured in liver cytosols correlated strongly with SULT1A1 enzyme protein levels measured by a quantitative immunoblot method. We therefore suggest that 2-aminophenol is a suitable substrate to use for quantifying SULT1A1 enzyme activity.
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Phenol sulfotransferase 1A1 activity in human liver: kinetic properties, interindividual variation and re-evaluation of the suitability of 4-nitrophenol as a probe substrate.
Biochemical Pharmacology, 2003Co-Authors: Catherine A. Tabrett, Michael W H CoughtrieAbstract:Abstract Sulfation is an important metabolic pathway in humans for xenobiotics, hormones and neurotransmitters, and is catalysed by the cytosolic sulfotransferase (SULT) enzymes. Phenol SULTs, especially SULT1A1, are particularly important in xenobiotic and drug metabolism because of their broad substrate specificity and extensive tissue distribution. A common variant SULT1A1 allozyme (SULT1A1 ∗ 2) exists in the population, and is less stable than the wild-type SULT1A1 ∗ 1. 4-Nitrophenol is widely used as a substrate for quantifying SULT1A1 activity. However, our kinetic experiments suggest that 4-nitrophenol is not an ideal substrate when determining SULT1A1 activity in human liver. Assays with a bank of 68 human liver cytosols revealed three distinct kinetic profiles for 4-nitrophenol sulfation in the population: linear, biphasic and inhibition. Sulfation of 4-nitrophenol by purified, recombinant SULT1A1 ∗ 1 and SULT1A1 ∗ 2 shows marked substrate inhibition, with inhibition at 4-nitrophenol concentrations greater than 4 and 10 μM, respectively. Furthermore, sulfation of 4-nitrophenol by purified recombinant SULT1B1 was significant at concentrations of 4-nitrophenol less than 10 μM. Western blots showed that the SULT1A1 levels in liver are highly variable between liver samples and that no correlation was observed between SULT1A1 activity and protein level in liver cytosols. However, a correlation between SULT1A1 activity and protein level was observed in human placental cytosols, where SULT1B1 is not expressed. We believe that in human liver other SULT isoforms (particularly SULT1B1) contribute to the sulfation of 4-nitrophenol. Therefore, 4-nitrophenol is not an ideal substrate with which to quantitate SULT1A1 activity in human liver tissue.
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sulfation of apomorphine by human sulfotransferases evidence of a major role for the polymorphic phenol sulfotransferase SULT1A1
Xenobiotica, 2003Co-Authors: N L Thomas, Michael W H CoughtrieAbstract:1. The relative roles of various members of the human sulfotransferase (SULT) enzyme family in the metabolism of apomorphine, a dopamine receptor antagonist used in the treatment of Parkinson's disease and, more recently, erectile dysfunction, were examined. In humans, sulfation is the major route of metabolism of this drug. 2. Using recombinant SULTs expressed in Escherichia coli, R(--)-apomorphine sulfation was studied using the universal barium precipitation assay in the presence of [35S] 3'-phosphoadenosine 5'-phosphosulfate and SULTs 1A1, 1A2, 1A3, 1B1, 1C2, 1E1 and 2A1. It was shown that SULTs 1A1, 1A2, 1A3 and 1E1 all sulfated apomorphine to varying extents. Low activity with SULT1B1 was only seen at the highest concentration (100 microM) and no activity with SULT1C2 or SULT2A1 was observed. 3. Kinetic analysis using purified recombinant SULTs showed that 1A1, 1A3 and 1E1 all had similar Vmax/Km values, although SULT1E1 had a slightly lower Km at around 1 microM compared with approximately 4 microM for the other SULTs. 4. By correlating apomorphine sulfation (at 10 microM) in a bank of 28 liver cytosols with SULT activity towards 10 microM 4-nitrophenol (SULT1A1) and 0.2 microM 17beta-oestradiol (SULT1E1), a strong correlation with SULT1A1 activity was clearly demonstrated, suggesting this enzyme was primarily responsible for hepatic apomorphine sulfation. 5. These findings were confirmed using immuno-inhibition experiments with antibodies against SULT1A and SULT1E1, which showed preferential inhibition of apomorphine sulfation in human liver cytosol by anti-SULT1A. 6. The results strongly implicate SULT1A1 as the major enzyme responsible for hepatic apomorphine metabolism. As SULT1A1 is subject to a common functional polymorphism, sulfation phenotype may be an important determinant of susceptibility to side-effects of apomorphine and/or efficacy of treatment.
Ming-cheh Liu - One of the best experts on this subject based on the ideXlab platform.
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Sulfation of catecholamines and serotonin by SULT1A3 allozymes.
Biochemical pharmacology, 2018Co-Authors: Ahsan F. Bairam, Yoichi Sakakibara, Masahito Suiko, Katsuhisa Kurogi, Mohammed I. Rasool, Fatemah A. Alherz, Maryam S. Abunnaja, Amal A. El Daibani, Saud A. Gohal, Ming-cheh LiuAbstract:Previous studies have demonstrated the involvement of sulfoconjugation in the metabolism of catecholamines and serotonin. The current study aimed to clarify the effects of single nucleotide polymorphisms (SNPs) of human SULT1A3 and SULT1A4 genes on the enzymatic characteristics of the sulfation of dopamine, epinephrine, norepinephrine and serotonin by SULT1A3 allozymes. Following a comprehensive search of different SULT1A3 and SULT1A4 genotypes, twelve non-synonymous (missense) coding SNPs (cSNPs) of SULT1A3/SULT1A4 were identified. cDNAs encoding the corresponding SULT1A3 allozymes, packaged in pGEX-2T vector were generated by site-directed mutagenesis. SULT1A3 allozymes were expressed, and purified. Purified SULT1A3 allozymes exhibited differential sulfating activity toward catecholamines and serotonin. Kinetic analyses demonstrated differences in both substrate affinity and catalytic efficiency of the SULT1A3 allozymes. Collectively, these findings provide useful information relevant to the differential metabolism of dopamine, epinephrine, norepinephrine and serotonin through sulfoconjugation in individuals having different SULT1A3/SULT1A4 genotypes.
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On the Molecular Basis Underlying the Metabolism of Tapentadol Through Sulfation.
European journal of drug metabolism and pharmacokinetics, 2017Co-Authors: Ahsan F. Bairam, Katsuhisa Kurogi, Mohammed I. Rasool, Ming-cheh LiuAbstract:Previous studies reported that tapentadol-sulfate represented one of the major metabolites of tapentadol excreted in urine. The current study aimed to identify the human cytosolic sulfotransferases (SULTs) that is(are) capable of sulfating tapentadol and to examine whether human cells and human organ specimens are capable of sulfating tapentadol. Thirteen human SULTs, previously expressed and purified, as well as human organ cytosols, were analyzed for tapentadol-sulfating activity using an established sulfotransferase assay. Cultured HepG2 human hepatoma cells and Caco-2 human colon carcinoma cells were labeled with [35S]sulfate in the presence of different concentrations of tapentadol. Three of the thirteen human SULTs, SULT1A1, SULT1A3, and SULT1C4, were found to display sulfating activity toward tapentadol. Kinetic analysis revealed that SULT1A3 displayed the highest catalytic efficiency in mediating the sulfation of tapentadol, followed by SULT1A1 and SULT1C4. Using cultured HepG2 and Caco-2 cells, the generation and release of sulfated tapentadol under metabolic conditions was demonstrated. Moreover, of the four human organ specimens (kidney, liver, lung, and small intestine) tested, the cytosols prepared from small intestine and liver showed significant tapentadol-sulfating capacity (at 0.0203 and 0.0054 nmol/min/mg, respectively). Taken together, the results derived from the current study provided a molecular basis underlying the sulfation of tapentadol in humans.
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Sulfation of benzyl alcohol by the human cytosolic sulfotransferases (SULTs): a systematic analysis.
Journal of applied toxicology : JAT, 2015Co-Authors: Lingtian Zhang, Yoichi Sakakibara, Masahito Suiko, Katsuhisa Kurogi, Ming-yih Liu, Alaina M. Schnapp, Frederick E. Williams, Ming-cheh LiuAbstract:The aim of the present study was to identify human cytosolic sulfotransferases (SULTs) that are capable of sulfating benzyl alcohol and to examine whether benzyl alcohol sulfation may occur in cultured human cells as well as in human organ homogenates. A systematic analysis revealed that of the 13 known human SULTs, SULT1A1 SULT1A2, SULTA3, and SULT1B1 are capable of mediating the sulfation of benzyl alcohol. The kinetic parameters of SULT1A1 that showed the strongest benzyl alcohol-sulfating activity were determined. HepG2 human hepatoma cells were used to demonstrate the generation and release of sulfated benzyl alcohol under the metabolic settings. Moreover, the cytosol or S9 fractions of human liver, lung, kidney and small intestine were examined to verify the presence of benzyl alcohol sulfating activity in vivo. Copyright © 2015 John Wiley & Sons, Ltd.
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sulfation of ritodrine by the human cytosolic sulfotransferases sults effects of sult1a3 genetic polymorphism
European Journal of Pharmacology, 2015Co-Authors: Ying Hui, Ming-cheh LiuAbstract:Previous studies have demonstrated the metabolism of ritodrine through sulfation. The current study was designed to identify the human SULTs that are capable of sulfating ritodrine and to investigate how genetic polymorphism of the major ritodrine-sulfating SULT, SULT1A3, may affect its sulfating activity. A systematic analysis revealed that of the 13 known human SULTs, SULT1A1, SULT1A3, and SULT1C4, were capable of mediating the sulfation of ritodrine, with SULT1A3 displaying the strongest sulfating activity. Effects of genetic polymorphism on the sulfating activity of SULT1A3 were examined. By employing site-directed mutagenesis, 4 SULT1A3 allozymes were generated, expressed, and purified. Purified SULT1A3 allozymes were shown to exhibit differential sulfating activity toward ritodrine. Kinetic studies further demonstrated differential substrate affinity and catalytic efficiency among the SULT1A3 allozymes. Collectively, these results provided useful information concerning the differential metabolism of ritodrine through sulfation in different individuals.
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crystal structures of sult1a2 and SULT1A1 3 insights into the substrate inhibition and the role of tyr149 in sult1a2
Biochemical and Biophysical Research Communications, 2010Co-Authors: Jiping Zhang, Ming-cheh Liu, Ming-yih Liu, Wenrui ChangAbstract:Abstract The cytosolic sulfotransferases (SULTs) in vertebrates catalyze the sulfonation of endogenous thyroid/steroid hormones and catecholamine neurotransmitters, as well as a variety of xenobiotics, using 3′-phosphoadenosine 5′-phosphosulfate (PAPS) as the sulfonate donor. In this study, we determined the structures of SULT1A2 and an allozyme of SULT1A1, SULT1A1∗3, bound with 3′-phosphoadenosine 5′-phosphate (PAP), at 2.4 and 2.3 A resolution, respectively. The conformational differences between the two structures revealed a plastic substrate-binding pocket with two channels and a switch-like substrate selectivity residue Phe247, providing clearly a structural basis for the substrate inhibition. In SULT1A2, Tyr149 extends approximately 2.1 A further to the inside of the substrate-binding pocket, compared with the corresponding His149 residue in SULT1A1∗3. Site-directed mutagenesis study showed that, compared with the wild-type SULT1A2, mutant Tyr149Phe SULT1A2 exhibited a 40 times higher K m and two times lower V max with p -nitrophenol as substrate. These latter data imply a significant role of Tyr149 in the catalytic mechanism of SULT1A2.
Richard M Weinshilboum - One of the best experts on this subject based on the ideXlab platform.
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Catecholestrogen Sulfation: Possible Role in Carcinogenesis ☆
Biochemical and biophysical research communications, 2002Co-Authors: Araba A. Adjei, Richard M WeinshilboumAbstract:Abstract A growing body of evidence supports the hypothesis that estrogens can be carcinogens as a result of their conversion to genotoxins after biotransformation to form the catecholestrogens (CEs) 2-hydroxyestrone (2-OHE1), 2-hydroxyestradiol (2-OHE2), 4-hydroxyestrone (4-OHE1) and 4-hydroxyestradiol (4-OHE2). CEs can then undergo further metabolism to form quinones that interact with DNA to form either stable or depurinating adducts. These events could potentially be interrupted by the sulfate conjugation of both the parent estrogens and/or the CEs. We set out to determine whether CEs can serve as substrates for sulfate conjugation, and—if so—which of the growing family of human sulfotransferase (SULT) isoforms are capable of catalyzing those reactions. We determined apparent Km values for 10 recombinant human SULT isoforms, as well as the three most common allozymes for SULT1A1 and SULT1A2, with 2-OHE1, 2-OHE2, 4-OHE1, and 4-OHE2, and with the endogenous estrogens, estrone (E1) and 17β-estradiol (E2), as substrates. With the exception of SULT1B1, SULT1C1, and SULT4A1, all of the human SULTs studied catalyzed the sulfate conjugation of CEs. SULT1E1 had the lowest apparent Km values, 0.31, 0.18, 0.27, and 0.22 μM for 4-OHE1, 4-OHE2, 2-OHE1, and 2-OHE2, respectively. These results demonstrate that SULTs can catalyze the sulfate conjugation of CEs, and they raise the possibility that individual variation in this pathway for estrogen and CE metabolism as a result of common genetic polymorphisms could represent a risk factor for estrogen-dependent carcinogenesis.
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sulfation pharmacogenetics SULT1A1 and sult1a2 allele frequencies in caucasian chinese and african american subjects
Pharmacogenetics, 2001Co-Authors: Edward J Carlini, Rebecca B Raftogianis, Thomas C Wood, Wei Zheng, Timothy R Rebbeck, Richard M WeinshilboumAbstract:Sulfotransferase (SULT) enzymes catalyze the sulfate conjugation of drugs, other xenobiotics, neurotransmitters and hormones. The genes for SULT1A1 and SULT1A2 contain common genetic polymorphisms that are associated with individual variations in levels of enzyme activity as well as variations in biochemical and physical properties. We set out to compare the frequencies of common SULT1A1 and SULT1A2 alleles in Caucasian, Chinese and African-American subjects. Allele frequencies for SULT1A11, 2 and 3 in 242 Caucasian subjects were 0.656, 0.332 and 0.012, respectively. Frequencies of those same alleles were significantly different in 290 Chinese subjects: 0.914, 0.080 and 0.006, respectively, as were frequencies in 70 African-American subjects: 0.477, 0.294 and 0.229, respectively. Ethnic variation in allele frequencies was also observed for SULT1A2, with frequencies in Caucasian subjects for SULT1A21, 2 and 3 of 0.507, 0.389 and 0.104; frequencies in Chinese of 0.924 and 0.076 with no3 alleles observed; and, finally, in African-Americans frequencies of 0.637, 0.249 and 0.114, respectively. We also found that SULT1A12 and SULT1A22, the most common variant alleles for these two genes, were in positive linkage disequilibrium in all three populations studied, with D9 values of 0.776 in Caucasian (P , 0.001), 0.915 in Chinese (P , 0.001) and 0.864 in African-American subjects (P , 0.001). These observations represent a step towards determining the possible functional implications for individual variations in sulfate conjugation of common genetic polymorphisms for SULT1A1 and SULT1A2. Pharmacogenetics 11:57‐68 # 2001 Lippincott Williams & Wilkins
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sulfation pharmacogenetics SULT1A1 and sult1a2 allele frequencies in caucasian chinese and african american subjects
Pharmacogenetics, 2001Co-Authors: Edward J Carlini, Rebecca B Raftogianis, Thomas C Wood, Wei Zheng, Timothy R Rebbeck, Fan Jin, Richard M WeinshilboumAbstract:Sulfotransferase (SULT) enzymes catalyze the sulfate conjugation of drugs, other xenobiotics, neurotransmitters and hormones. The genes for SULT1A1 and SULT1A2 contain common genetic polymorphisms that are associated with individual variations in levels of enzyme activity as well as variations in biochemical and physical properties. We set out to compare the frequencies of common SULT1A1 and SULT1A2 alleles in Caucasian, Chinese and African-American subjects. Allele frequencies for SULT1A11, 2 and 3 in 242 Caucasian subjects were 0.656, 0.332 and 0.012, respectively. Frequencies of those same alleles were significantly different in 290 Chinese subjects: 0.914, 0.080 and 0.006, respectively, as were frequencies in 70 African-American subjects: 0.477, 0.294 and 0.229, respectively. Ethnic variation in allele frequencies was also observed for SULT1A2, with frequencies in Caucasian subjects for SULT1A21, 2 and 3 of 0.507, 0.389 and 0.104; frequencies in Chinese of 0.924 and 0.076 with no3 alleles observed; and, finally, in African-Americans frequencies of 0.637, 0.249 and 0.114, respectively. We also found that SULT1A12 and SULT1A22, the most common variant alleles for these two genes, were in positive linkage disequilibrium in all three populations studied, with D9 values of 0.776 in Caucasian (P , 0.001), 0.915 in Chinese (P , 0.001) and 0.864 in African-American subjects (P , 0.001). These observations represent a step towards determining the possible functional implications for individual variations in sulfate conjugation of common genetic polymorphisms for SULT1A1 and SULT1A2. Pharmacogenetics 11:57‐68 # 2001 Lippincott Williams & Wilkins
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human phenol sulfotransferases sult1a2 and SULT1A1 genetic polymorphisms allozyme properties and human liver genotype phenotype correlations
Biochemical Pharmacology, 1999Co-Authors: Rebecca B Raftogianis, Thomas C Wood, Richard M WeinshilboumAbstract:Abstract Phenol sulfotransferases (PSTs or phenol SULTs) catalyze the sulfate conjugation of phenolic drugs, xenobiotics, and monoamines. Two human PST isoforms have been defined biochemically, a thermostable (TS), or phenol-preferring, and a thermolabile (TL), or monoamine-preferring form. Pharmacogenetic studies showed that levels of both TS PST activity and TS PST thermal stability (an indirect measure of variation in amino acid sequence) in the platelet were regulated by genetic polymorphisms. Subsequent molecular genetic experiments revealed the existence of three human PST genes, two of which, SULT1A1 and SULT1A2, encode proteins with “TS PST-like” activity. We recently reported common nucleotide polymorphisms for SULT1A1 that are associated with variations in platelet TS PST activity and thermal stability. In the present experiments, we set out to determine whether functionally significant DNA polymorphisms also might exist for SULT1A2, to compare the biochemical properties of all common allozymes encoded by SULT1A2 and SULT1A1, and to study phenol SULT genotype–phenotype correlations in the human liver. We phenotyped 61 human liver biopsy samples for TS PST thermal stability and activity. The open reading frames of SULT1A2 and SULT1A1 then were amplified with the polymerase chain reaction and sequenced for each of these hepatic tissue samples. We observed 13 SULT1A2 alleles that encoded 6 allozymes. These alleles were in linkage disequilibrium with alleles for SULT1A1. Biochemical characterization of common allozymes encoded by both genes suggested that SULT1A1 was primarily responsible for “TS PST phenotype” in the human liver. In summary, both SULT1A2 and SULT1A1 have a series of common alleles encoding enzymes that differ functionally and are associated with individual differences in phenol SULT properties in the liver.
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phenol sulfotransferase pharmacogenetics in humans association of common SULT1A1 alleles with ts pst phenotype
Biochemical and Biophysical Research Communications, 1997Co-Authors: Rebecca B Raftogianis, Thomas C Wood, Diane M Otterness, Jon A Van Loon, Richard M WeinshilboumAbstract:The phenol sulfotransferases (PSTs) catalyze the sulfation of both small planar phenols and phenolic monoamines. Three highly homologous PST genes, SULT1A1, SULT1A2, and SULT1A3, are known to exist in humans. The prototypic biochemical phenotype associated with the enzyme encoded by SULT1A1 is the thermal stable (TS) sulfation of 4 microM 4-nitrophenol (TS PST activity). Biochemical pharmacogenetic studies have demonstrated that individual variation in both TS PST activity and thermal stability in humans are inherited. As a step toward understanding molecular mechanisms responsible for the genetic regulation of PSTs in humans, we report here common SULT1A1 nucleotide polymorphisms that are associated with phenotypic variation in both platelet TS PST activity and thermal stability. When 905 human subjects were phenotyped for platelet TS PST activity and thermal stability, activity varied more than 50-fold, and thermal stability varied over 10-fold. DNA was isolated from the blood of 33 of these subjects selected on the basis of "extreme" TS PST phenotypes: high activity and high thermal stability; low activity and low thermal stability; or low activity and high thermal stability. These 33 subjects were genotyped for SULT1A1 by PCR amplification and sequencing of the entire open reading frame (ORF) as well as approximately 1 kb of intron DNA sequence. One common allele, SULT1A1*2, was uniformly associated with both very low TS PST activity and low thermal stability. The allele frequency of SULT1A1*2 in a randomly selected population sample of 150 Caucasian blood donors was 0.31 (31%), indicating that approximately 9% of this population would be homozygous for that allele.
