7-Benzyloxyresorufin-O-dealkylase activity as a marker for measuring cytochrome P450 CYP3A induction in mouse liver

Hagemeyer, Christoph E.; Bürck, Carolin; Schwab, Ricarda; Knoth, Rolf; Meyer, Ralf Peter

doi:10.1016/j.ab.2009.11.004

Cited by 25 publications

(18 citation statements)

References 34 publications

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“…This cannot be attributed to Cyp2b10 (Figs. 2D and 4) but could be explained by the increase in Cyp3a13 in this tissue (Hagemeyer et al, 2010). The Cyp2b substrate pentoxyresorufin (Chatuphonprasert et al, 2012) showed only a small increase in turnover (1.7-fold) in hepatic samples from Cyp2c/2d/3a KO mice compared with WT controls, suggesting that P450s other than Cyp2b10 (Fig.…”

Section: Resultsmentioning

confidence: 94%

Deletion of 30 Murine Cytochrome P450 Genes Results In Viable Mice With Compromised Drug Metabolism

et al. 2014

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In humans, 75% of all drugs are metabolized by the cytochrome P450-dependent monooxygenase system. Enzymes encoded by the CYP2C, CYP2D, and CYP3A gene clusters account for ∼80% of this activity. There are profound species differences in the multiplicity of cytochrome P450 enzymes, and the use of mouse models to predict pathways of drug metabolism is further complicated by overlapping substrate specificity between enzymes from different gene families. To establish the role of the hepatic and extrahepatic P450 system in drug and foreign chemical disposition, drug efficacy, and toxicity, we created a unique mouse model in which 30 cytochrome P450 genes from the Cyp2c, Cyp2d, and Cyp3a gene clusters have been deleted. Remarkably, despite a wide range of putative important endogenous functions, Cyp2c/2d/3a KO mice were viable and fertile, demonstrating that these genes have evolved primarily as detoxification enzymes. Although there was no overt phenotype, detailed examination showed Cyp2c/2d/3a KO mice had a smaller body size (15%) and larger livers (20%). Changes in hepatic morphology and a decreased blood glucose (30%) were also noted. A five-drug cocktail of cytochrome P450 isozyme probe substrates were used to evaluate changes in drug pharmacokinetics; marked changes were observed in either the pharmacokinetics or metabolites formed from Cyp2c, Cyp2d, and Cyp3a substrates, whereas the metabolism of the Cyp1a substrate caffeine was unchanged. Thus, Cyp2c/2d/3a KO mice provide a powerful model to study the in vivo role of the P450 system in drug metabolism and efficacy, as well as in chemical toxicity.

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Section: Resultsmentioning

confidence: 94%

Deletion of 30 Murine Cytochrome P450 Genes Results In Viable Mice With Compromised Drug Metabolism

et al. 2014

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“…A similar approach was adopted for the MF‐exposed DIV‐BBB (n = 4 donors in triplicate per condition). Samples (200 μL) were collected from the luminal and abluminal sides of the DIV‐BBB at 0, 2, 4, 6, and 24 hours (Appendix ) . A standard plot for resorufin (5‐200 nmol/L) is shown in Figure .…”

Section: Methodsmentioning

confidence: 99%

Modulation of glucocorticoid receptor in human epileptic endothelial cells impacts drug biotransformation in an in vitro blood–brain barrier model

et al. 2018

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SummaryObjectiveNuclear receptors and cytochrome P450 (CYP) regulate hepatic metabolism of several drugs. Nuclear receptors are expressed at the neurovascular unit of patients with drug‐resistant epilepsy. We studied whether glucocorticoid receptor (GR) silencing or inhibition in human epileptic brain endothelial cells (EPI‐ECs) functionally impacts drug bioavailability across an in vitro model of the blood–brain barrier (BBB) by CYP‐multidrug transporter (multidrug resistance protein 1, MDR1) mechanisms.MethodsSurgically resected brain specimens from patients with drug‐resistant epilepsy, primary EPI‐ECs, and control human brain microvascular endothelial cells (HBMECs) were used. Expression of GR, pregnane X receptor, CYP3A4, and MDR1 was analyzed pre‐ and post‐GR silencing in EPI‐ECs. Endothelial cells were co‐cultured with astrocytes and seeded in an in vitro flow‐based BBB model (DIV‐BBB). Alternatively, the GR inhibitor mifepristone was added to the EPI‐EC DIV‐BBB. Integrity of the BBB was monitored by measuring transendothelial electrical resistance. Cell viability was assessed by glucose‐lactate levels. Permeability of [3H]sucrose and [14C]phenytoin was quantified. CYP function was determined by measuring resorufin formation and oxcarbazepine (OXC) metabolism.ResultsSilencing and inhibition of GR in EPI‐ECs resulted in decreased pregnane X receptor, CYP3A4, and MDR1 expression. GR silencing or inhibition did not affect BBB properties in vitro, as transendothelial electrical resistance and Psucrose were unaltered, and glucose metabolism was maintained. GR EPI‐EC silencing or inhibition led to (1) increased Pphenytoin BBB permeability as compared to control; (2) decreased CYP function, indirectly evaluated by resorufin formation; (3) improved OXC bioavailability with increased abluminal (brain‐side) OXC levels as compared to control.SignificanceOur results suggest that modulating GR expression in EPI‐ECs at the BBB modifies drug metabolism and penetration by a mechanism encompassing P450 and efflux transporters. The latter could be exploited for future drug design and to overcome pharmacoresistance.

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“…In mice, O-dealkylation of 7-ethoxyresorufin is catalyzed by CYP1A1 and CYP1A2 [15], and O-dealkylation of 7-benzyloxyresorufin by CYP3A11 enzyme [16]. The activities of CYP1A and CYP3A were determined as a rate of ethoxy- (EROD) and benzyloxy- (BROD) resorufin O-dealkylation, respectively.…”

Section: Methodsmentioning

confidence: 99%

Effect of Naringenin, Quercetin, and Sesamin on Xenobiotica-Metabolizing CYP1A and CYP3A in Mice Offspring after Maternal Exposure to Persistent Organic Pollutants

Pilipenko

Ropstad

Halsne

et al. 2017

BioMed Research International

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The aim of the present study was to evaluate in vitro effects of dietary phytochemicals naringenin, quercetin, and sesamin on the activities of ethoxy- (EROD; CYP1A) and benzyloxy- (BROD; CYP3A) resorufin O-dealkylases after the exposure to the cocktail of persistent organic pollutants (POPs). CD-1 mice were exposed from weaning, through gestation and lactation to a defined mixture of POPs. Hepatic microsomes were prepared from their female offspring at postnatal day 42. Hepatic EROD and BROD activity were evaluated in the presence of quercetin, naringenin, and sesamin at nine concentrations from 5 to 100000 nM. EROD activity was strongly inhibited by quercetin with Ki values from 1.7 to 2.6 μM. BROD activity was inhibited by quercetin with Ki values from 64.9 to 75.3 μM and naringenin with Ki values from 39.3 to 45.8 μM. The IC50 and Ki values did not differ between the groups of mice with different levels of POPs exposure in any of the experimental sets. Sesamin did not inhibit either EROD or BROD. We concluded that the interactions of quercetin and naringenin with CYP1A and CYP3A in mice liver were not affected by the levels of POPs exposure.

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7-Benzyloxyresorufin-O-dealkylase activity as a marker for measuring cytochrome P450 CYP3A induction in mouse liver

Cited by 25 publications

References 34 publications

Deletion of 30 Murine Cytochrome P450 Genes Results In Viable Mice With Compromised Drug Metabolism

Deletion of 30 Murine Cytochrome P450 Genes Results In Viable Mice With Compromised Drug Metabolism

Modulation of glucocorticoid receptor in human epileptic endothelial cells impacts drug biotransformation in an in vitro blood–brain barrier model

Effect of Naringenin, Quercetin, and Sesamin on Xenobiotica-Metabolizing CYP1A and CYP3A in Mice Offspring after Maternal Exposure to Persistent Organic Pollutants

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