scholarly journals Urinary Elimination of Bile Acid Glucuronides under Severe Cholestatic Situations: Contribution of Hepatic and Renal Glucuronidation Reactions

2018 ◽  
Vol 2018 ◽  
pp. 1-12 ◽  
Author(s):  
Martin Perreault ◽  
Ewa Wunsch ◽  
Andrzej Białek ◽  
Jocelyn Trottier ◽  
Mélanie Verreault ◽  
...  
Keyword(s):  
Biliary Obstruction ◽  
Human Liver ◽  
Tandem Mass ◽  
Protein Levels ◽  
Liver And Kidney ◽  
Kidney Microsomes ◽  
Udp Glucuronosyltransferase ◽  
Serum And Urine ◽  
Serum And Urine Samples

Biliary obstruction, a severe cholestatic complication, causes accumulation of toxic bile acids (BAs) in liver cells. Glucuronidation, catalyzed by UDP-glucuronosyltransferase (UGT) enzymes, detoxifies cholestatic BAs. Using liquid chromatography coupled to tandem mass spectrometry, 11 BA glucuronide (-G) species were quantified in prebiliary and postbiliary stenting serum and urine samples from 17 patients with biliary obstruction. Stenting caused glucuronide- and fluid-specific changes in BA-G levels and BA-G/BA metabolic ratios. In vitro glucuronidation assays with human liver and kidney microsomes revealed that even if renal enzymes generally displayed lower KM values, the two tissues shared similar glucuronidation capacities for BAs. By contrast, major differences between the two tissues were observed when four human BA-conjugating UGTs 1A3, 1A4, 2B4, and 2B7 were analyzed for mRNA and protein levels. Notably, the BA-24G producing UGT1A3 enzyme, abundant in the liver, was not detected in kidney microsomes. In conclusion, the circulating and urinary BA-G profiles are hugely impacted under severe cholestasis. The similar BA-glucuronidating abilities of hepatic and renal extracts suggest that both the liver and kidney may contribute to the urine BA-G pool.

Characterizations of Human UDP-Glucuronosyltransferase Enzymes in the Conjugation of p-Cresol

2020 ◽  
Vol 176 (2) ◽  
pp. 285-296 ◽  
Author(s):  
Yan Rong ◽  
Tony K L Kiang
Keyword(s):  
Human Liver ◽  
Substrate Inhibition ◽  
Liver Microsomes ◽  
Human Kidney ◽  
Human Liver Microsomes ◽  
Uremic Toxin ◽  
Inverse Association ◽  
Kidney Microsomes ◽  
Udp Glucuronosyltransferase

Abstract p-Cresol is a uremic toxin that is formed by intestinal microbiota and extensively conjugated by first-pass metabolism. p-Cresol glucuronide exerts various forms of cellular toxicity in vitro and is accumulated in the plasma of subjects with kidney disease, where associations with adverse cardiovascular and renal outcomes are evident. The objective of this study was to determine the contributions of human UDP-glucuronosyltransferase (UGT) enzymes in the formation of p-cresol glucuronide. Utilizing commonly expressed hepatic or renal human recombinant UGTs (ie, hrUGT1A1, 1A3, 1A4, 1A6, 1A7, 1A8, 1A9, 1A10, 2B4, 2B7, 2B10, 2B15, and 2B17), hrUGT1A6 and hrUGT1A9 exhibited the highest catalytic activities in the generation of p-cresol glucuronide. The kinetics of p-cresol glucuronide formation in hrUGT1A6 and pooled human liver microsomes were best described by the Hill equation and in hrUGT1A9 and pooled human kidney microsomes by substrate inhibition. Using inhibitory and selective UGT inhibitors (ie, acetaminophen or amentoflavone for UGT1A6 and niflumic acid for UGT1A9), UGT1A6 was identified the predominant enzyme responsible for p-cresol glucuronide production in pooled human liver (78.4%–81.3% contribution) and kidney (54.3%–62.9%) microsomes, whereas UGT1A9 provided minor contributions (2.8% and 35.5%, respectively). The relative contributions of UGT1A6 (72.6 ± 11.3%, mean ± SD) and UGT1A9 (5.7 ± 4.1%) in individual human liver microsomes from 12 adult donors were highly variable, where an inverse association (R = −.784, p = .003) between UGT1A6 contribution and UGT1A9 probe substrate activity (ie, mycophenolic acid) was evident. Our novel findings provide valuable tools for conducting further mechanistic studies and for designing clinical interventions to mitigate the toxicities associated with p-cresol glucuronide.

AAnti-Inflammatory Effects of Plasma Circulating Exosomes Obtained from Normal-Weight and Obese Subjects on Hepatocytes

2020 ◽  
Vol 20 ◽  
Author(s):  
Reza Afrisham ◽  
Sahar Sadegh-Nejadi ◽  
Reza Meshkani ◽  
Solaleh Emamgholipour ◽  
Molood Bagherieh ◽  
...  
Keyword(s):  
Inflammatory Cytokines ◽  
Hepg2 Cells ◽  
Human Liver ◽  
Liver Cells ◽  
Normal Weight ◽  
Protein Levels ◽  
Human Liver Cells ◽  
Tnf Α ◽  
Anti Inflammatory

Introduction: Obesity is a disorder with low-grade chronic inflammation that plays a key role in the hepatic inflammation and steatosis. Moreover, there are studies to support the role of exosomes in the cellular communications, the regulation of metabolic homeostasis and immunomodulatory activity. Accordingly, we aimed to evaluate the influence of plasma circulating exosomes derived from females with normal-weight and obesity on the secretion of inflammatory cytokines in human liver cells. Methods: Plasma circulating exosomes were isolated from four normal (N-Exo) and four obese (O-Exo) women. The exosomes were characterized and approved for CD63 expression (common exosomal protein marker) and morphology/size using the western blot and TEM methods, respectively. The exosomes were used for stimulation of HepG2 cells in vitro. After 24 h incubation, the protein levels of TNF-α,IL-6, and IL-1β were measured in the culture supernatant of HepG2 cells using the ELISA kit. Results: The protein levels of IL-6 and TNF-α in the cells treated with O-Exo and N-Exo reduced significantly in comparison with control group (P=0.039 and P<0.001 respectively), while significance differences were not found between normal and obese groups (P=0.808, and P=0.978 respectively). However, no significant differences were found between three groups in term of IL-1β levels (P=0.069). Based on the correlation analysis, the protein levels of IL-6 were positively correlated with TNF-α (r 0.978, P<0.001). Conclusion: These findings suggest that plasma circulating exosomes have probably anti-inflammatory properties independently from body mass index and may decrease the secretion of inflammatory cytokines in liver. However, further investigations in vitro and in vivo are needed to address the anti-inflammatory function of N-Exo and O-Exo in human liver cells and/or other cells.

scholarly journals Identification of Catalposide Metabolites in Human Liver and Intestinal Preparations and Characterization of the Relevant Sulfotransferase, UDP-glucuronosyltransferase, and Carboxylesterase Enzymes

Pharmaceutics ◽  
2019 ◽  
Vol 11 (7) ◽  
pp. 355 ◽  
Author(s):  
Deok-Kyu Hwang ◽  
Ju-Hyun Kim ◽  
Yongho Shin ◽  
Won-Gu Choi ◽  
Sunjoo Kim ◽  
...  
Keyword(s):  
Human Liver ◽  
Individual Variability ◽  
Hydroxybenzoic Acid ◽  
Catalpa Ovata ◽  
Anti Oxidant ◽  
Extrahepatic Tissues ◽  
Udp Glucuronosyltransferase ◽  
Hydrolysis Of

Catalposide, an active component of Veronica species such as Catalpa ovata and Pseudolysimachion lingifolium, exhibits anti-inflammatory, antinociceptic, anti-oxidant, hepatoprotective, and cytostatic activities. We characterized the in vitro metabolic pathways of catalposide to predict its pharmacokinetics. Catalposide was metabolized to catalposide sulfate (M1), 4-hydroxybenzoic acid (M2), 4-hydroxybenzoic acid glucuronide (M3), and catalposide glucuronide (M4) by human hepatocytes, liver S9 fractions, and intestinal microsomes. M1 formation from catalposide was catalyzed by sulfotransferases (SULTs) 1C4, SULT1A1*1, SULT1A1*2, and SULT1E1. Catalposide glucuronidation to M4 was catalyzed by gastrointestine-specific UDP-glucuronosyltransferases (UGTs) 1A8 and UGT1A10; M4 was not detected after incubation of catalposide with human liver preparations. Hydrolysis of catalposide to M2 was catalyzed by carboxylesterases (CESs) 1 and 2, and M2 was further metabolized to M3 by UGT1A6 and UGT1A9 enzymes. Catalposide was also metabolized in extrahepatic tissues; genetic polymorphisms of the carboxylesterase (CES), UDP-glucuronosyltransferase (UGT), and sulfotransferase (SULT) enzymes responsible for catalposide metabolism may cause inter-individual variability in terms of catalposide pharmacokinetics.

scholarly journals Identification of Human Sulfotransferases Active towards Silymarin Flavonolignans and Taxifolin

Metabolites ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 329
Author(s):  
Jiří Vrba ◽  
Barbora Papoušková ◽  
Pavel Kosina ◽  
Kateřina Lněničková ◽  
Kateřina Valentová ◽  
...  
Keyword(s):  
Human Liver ◽  
High Performance ◽  
Herbal Remedy ◽  
Expression Patterns ◽  
Human Hepatocytes ◽  
Tandem Mass ◽  
Recombinant Enzymes ◽  
Metabolic Reactions ◽  
Natural Phenolic Compounds

Natural phenolic compounds are known to be metabolized by phase II metabolic reactions. In this study, we examined the in vitro sulfation of the main constituents of silymarin, an herbal remedy produced from the fruits of the milk thistle. The study focused on major flavonolignan constituents, including silybin A, silybin B, isosilybin A, isosilybin B, silychristin, and silydianin, as well as the flavonoid taxifolin. Using ultra-high-performance liquid chromatography coupled with tandem mass spectrometry (UHPLC-MS), individual flavonolignans and taxifolin were found to be sulfated by human liver and human intestinal cytosols. Moreover, experiments with recombinant enzymes revealed that human sulfotransferases (SULTs) 1A1*1, 1A1*2, 1A2, 1A3, 1B1, 1C4, and 1E1 catalyzed the sulfation of all of the tested compounds, with the exception of silydianin, which was not sulfated by SULT1B1 and SULT1C4. The sulfation products detected were monosulfates, of which some of the major ones were identified as silybin A 20-O-sulfate, silybin B 20-O-sulfate, and isosilybin A 20-O-sulfate. Further, we also observed the sulfation of the tested compounds when they were tested in the silymarin mixture. Sulfates of flavonolignans and of taxifolin were produced by incubating silymarin with all of the above SULT enzymes, with human liver and intestinal cytosols, and also with human hepatocytes, even though the spectrum and amount of the sulfates varied among the metabolic models. Considering our results and the expression patterns of human sulfotransferases in metabolic tissues, we conclude that flavonolignans and taxifolin can potentially undergo both intestinal and hepatic sulfation, and that SULTs 1A1, 1A3, 1B1, and 1E1 could be involved in the biotransformation of the constituents of silymarin.

scholarly journals Effect of a New Prokinetic Agent DA-9701 Formulated with Corydalis Tuber and Pharbitidis Semen on Cytochrome P450 and UDP-Glucuronosyltransferase Enzyme Activities in Human Liver Microsomes

2012 ◽  
Vol 2012 ◽  
pp. 1-7 ◽  
Author(s):  
Hye Young Ji ◽  
Kwang Hyeon Liu ◽  
Ji Hyeon Jeong ◽  
Dae-Young Lee ◽  
Hyun Joo Shim ◽  
...  
Keyword(s):  
Cytochrome P450 ◽  
Human Liver ◽  
Liver Microsomes ◽  
Human Liver Microsomes ◽  
Udp Glucuronosyltransferase ◽  
Index Value ◽  
Tuber Extract ◽  
Corydalis Tuber

DA-9701 is a new botanical drug composed of the extracts of Corydalis tuber and Pharbitidis semen, and it is used as an oral therapy for the treatment of functional dyspepsia in Korea. The inhibitory potentials of DA-9701 and its component herbs, Corydalis tuber and Pharbitidis semen, on the activities of seven major human cytochrome P450 (CYP) enzymes and four UDP-glucuronosyltransferase (UGT) enzymes in human liver microsomes were investigated using liquid chromatography-tandem mass spectrometry. DA-9701 and Corydalis tuber extract slightly inhibited UGT1A1-mediated etoposide glucuronidation, with 50% inhibitory concentration (IC50) values of 188 and 290 μg/mL, respectively. DA-9701 inhibited CYP2D6-catalyzed bufuralol1′-hydroxylation with an inhibition constant (Ki) value of 6.3 μg/mL in a noncompetitive manner. Corydalis tuber extract competitively inhibited CYP2D6-mediated bufuralol1′-hydroxylation, with aKivalue of 3.7 μg/mL, whereas Pharbitidis semen extract showed no inhibition. The volume in which the dose could be diluted to generate an IC50equivalent concentration (volume per dose index) value of DA-9701 for inhibition of CYP2D6 activity was 1.16 L/dose, indicating that DA-9701 may not be a potent CYP2D6 inhibitor. Further clinical studies are warranted to evaluate thein vivoextent of the observedin vitrointeractions.

scholarly journals Aldosterone glucuronidation by human liver and kidney microsomes and recombinant UDP-glucuronosyltransferases: Inhibition by NSAIDs

2009 ◽  
Vol 68 (3) ◽  
pp. 402-412 ◽  
Author(s):  
Kathleen M. Knights ◽  
Leanne K. Winner ◽  
David J. Elliot ◽  
Kushari Bowalgaha ◽  
John O. Miners
Keyword(s):  
Human Liver ◽  
Liver And Kidney ◽  
Kidney Microsomes

scholarly journals Enantiomer Selective Glucuronidation of the Non-Steroidal Pure Anti-Androgen Bicalutamide by Human Liver and Kidney: Role of the Human UDP-Glucuronosyltransferase (UGT)1A9 Enzyme

2013 ◽  
Vol 113 (2) ◽  
pp. 92-102 ◽  
Author(s):  
Laurent Grosse ◽  
Anne-Sophie Campeau ◽  
Sarah Caron ◽  
Frédéric-Alexandre Morin ◽  
Kim Meunier ◽  
...  
Keyword(s):  
Human Liver ◽  
Liver And Kidney ◽  
Udp Glucuronosyltransferase
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