scholarly journals Proteomic profiling of murine biliary-derived hepatic organoids and their capacity for drug disposition, bioactivation and detoxification

2021 ◽  
Author(s):  
Lawrence Howell ◽  
Rosalind E. Jenkins ◽  
Stephen Lynch ◽  
Carrie Duckworth ◽  
B. Kevin Park ◽  
...  
Keyword(s):  
Cytochrome P450 ◽  
Drug Metabolism ◽  
Rna Polymerase Ii ◽  
Liver Tissue ◽  
Drug Disposition ◽  
Multiple Drug ◽  
Proteomic Profiling ◽  
Cytochrome P450 3A ◽  
Drug Induced

AbstractHepatic organoids are a recent innovation in in vitro modeling. Initial studies suggest that organoids better recapitulate the liver phenotype in vitro compared to pre-existing proliferative cell models. However, their potential for drug metabolism and detoxification remains poorly characterized, and their global proteome has yet to be compared to their tissue of origin. This analysis is urgently needed to determine what gain-of-function this new model may represent for modeling the physiological and toxicological response of the liver to xenobiotics. Global proteomic profiling of undifferentiated and differentiated hepatic murine organoids and donor-matched livers was, therefore, performed to assess both their similarity to liver tissue, and the expression of drug-metabolizing enzymes and transporters. This analysis quantified 4405 proteins across all sample types. Data are available via ProteomeXchange (PXD017986). Differentiation of organoids significantly increased the expression of multiple cytochrome P450, phase II enzymes, liver biomarkers and hepatic transporters. While the final phenotype of differentiated organoids is distinct from liver tissue, the organoids contain multiple drug metabolizing and transporter proteins necessary for liver function and drug metabolism, such as cytochrome P450 3A, glutathione-S-transferase alpha and multidrug resistance protein 1A. Indeed, the differentiated organoids were shown to exhibit increased sensitivity to midazolam (10–1000 µM) and irinotecan (1–100 µM), when compared to the undifferentiated organoids. The predicted reduced activity of HNF4A and a resulting dysregulation of RNA polymerase II may explain the partial differentiation of the organoids. Although further experimentation, optimization and characterization is needed relative to pre-existing models to fully contextualize their use as an in vitro model of drug-induced liver injury, hepatic organoids represent an attractive novel model of the response of the liver to xenobiotics. The current study also highlights the utility of global proteomic analyses for rapid and accurate evaluation of organoid-based test systems.

scholarly journals Inhibition of Human Cytochrome P450 Metabolism by Blended Herbal Products and Vitamins

2011 ◽  
Vol 14 (1) ◽  
pp. 1 ◽  
Author(s):  
Teresa W Tam ◽  
Humayoun Akhtar ◽  
John Thor Arnason ◽  
Kosta Cvijovic ◽  
Heather Boon ◽  
...  
Keyword(s):  
Adverse Event ◽  
Cytochrome P450 ◽  
Drug Metabolism ◽  
Drug Disposition ◽  
Natural Health Products ◽  
Carotene Content ◽  
Herbal Products ◽  
Cytochrome P450 Activity ◽  
Health Products

Purpose. The use of supplements as herbal and micronutrient natural health products with conventional health products has become increasingly popular. It has been reported that some herbal products can inhibit the activity of cytochrome P450-mediated metabolism and drug disposition. This study was designed to investigate a case report of a severe adverse event to determine the potential interactions of femMED, Thyrosense and vitamins on cytochrome P450-mediated drug metabolism. Methods. The effect of extracts from these commercially available herbal formulations, trans-ß-carotene, multivitamins, and vitamin D3 supplements on cytochrome P450-mediated drug metabolism of marker substrates was determined in vitro. Results. The blended herbal products femMED and Thyrosense had a high potential to affect the safety and efficacy of many health products. Some vitamin and trans-β-carotene containing products also have the potential to affect drug disposition. The ß-carotene content of various products was analyzed and significant discrepancies were found among them and between values indicated on product labels. Product extracts also exhibited a low to moderate capacity to inhibit cytochrome P450 2C9, 2C19 and 3A4-mediated metabolism. Conclusions. The findings of this study suggest that these herbal products and most vitamin products may have an inhibitory effect on cytochrome P450 activity that could contribute to development of an adverse event. Further work is warranted to determine how supplementation with these products may affect drug metabolism in an in vivo context.

scholarly journals Sequencing of the Canine Cytochrome P450 CYP2C41 Gene and Genotyping of Its Polymorphic Occurrence in 36 Dog Breeds

2021 ◽  
Vol 8 ◽  
Author(s):  
Emre Karakus ◽  
Clarissa Prinzinger ◽  
Silke Leiting ◽  
Joachim Geyer
Keyword(s):  
Cytochrome P450 ◽  
Drug Metabolism ◽  
Gene Deletion ◽  
Homologous Sequence ◽  
Pharmacokinetic Studies ◽  
Metabolizing Enzymes ◽  
Genomic Level ◽  
Very High

Cytochrome P450 (CYP) drug metabolizing enzymes play an important role in efficient drug metabolism and elimination. Many CYPs are polymorphic and, thereby, drug metabolism can vary between individuals. In the case of canine CYP2C41, gene polymorphism was identified. However, as the first available canine genome sequences all were CYP2C41 negative, this polymorphism could not be clarified at the genomic level. The present study provides an exact characterization of the CYP2C41 gene deletion polymorphism at the genomic level and presents a PCR-based genotyping method that was used for CYP2C41 genotyping of 1,089 individual subjects from 36 different dog breeds. None of the Bearded Collie, Bernese Mountain, Boxer, Briard, French Bulldog or Irish Wolfhound subjects had the CYP2C41 gene in their genomes. In contrast, in the Chinese Char-Pei, Siberian Husky, Schapendoes and Kangal breeds, the CYP2C41 allele frequency was very high, with values of 67, 57, 43, and 34%, respectively. Interestingly, the site of gene deletion was identical for all CYP2C41 negative dogs, and all CYP2C41 positive dogs showed highly homologous sequence domains upstream and downstream from the CYP2C41 gene. CYP2C41 genotyping can now be routinely used in future pharmacokinetic studies in canines, in order to identify genetically-based poor or extensive drug metabolizers. This, together with more extensive in vitro drug screening for CYP2C41 substrates will help to determine the clinical relevance of CYP2C41, and to optimize drug treatment. Although the relative abundance of the CYP2C41 protein in the canine liver seems to not be very high, this CYP could substantially contribute to hepatic drug metabolism in dogs expressing CYP2C41 from both alleles and, when CYP2C41 shows higher catalytic activity to a given drug than other hepatic metabolic enzymes.

scholarly journals Mechanism of RNA polymerase II stalling by DNA alkylation

2017 ◽  
Vol 114 (46) ◽  
pp. 12172-12177 ◽  
Author(s):  
Stefano Malvezzi ◽  
Lucas Farnung ◽  
Claudia M. N. Aloisi ◽  
Todor Angelov ◽  
Patrick Cramer ◽  
...  
Keyword(s):  
Rna Polymerase ◽  
Rna Polymerase Ii ◽  
Anticancer Agents ◽  
Excision Repair ◽  
Minor Groove ◽  
Dna Alkylation ◽  
Drug Induced ◽  
Rna Pol Ii ◽  
Pol Ii

Several anticancer agents that form DNA adducts in the minor groove interfere with DNA replication and transcription to induce apoptosis. Therapeutic resistance can occur, however, when cells are proficient in the removal of drug-induced damage. Acylfulvenes are a class of experimental anticancer agents with a unique repair profile suggesting their capacity to stall RNA polymerase (Pol) II and trigger transcription-coupled nucleotide excision repair. Here we show how different forms of DNA alkylation impair transcription by RNA Pol II in cells and with the isolated enzyme and unravel a mode of RNA Pol II stalling that is due to alkylation of DNA in the minor groove. We incorporated a model for acylfulvene adducts, the stable 3-deaza-3-methoxynaphtylethyl-adenosine analog (3d-Napht-A), and smaller 3-deaza-adenosine analogs, into DNA oligonucleotides to assess RNA Pol II transcription elongation in vitro. RNA Pol II was strongly blocked by a 3d-Napht-A analog but bypassed smaller analogs. Crystal structure analysis revealed that a DNA base containing 3d-Napht-A can occupy the +1 templating position and impair closing of the trigger loop in the Pol II active center and polymerase translocation into the next template position. These results show how RNA Pol II copes with minor-groove DNA alkylation and establishes a mechanism for drug resistance.

Nitric Oxide Mediates Hepatic Cytochrome P450 Dysfunction Induced by Endotoxin

1996 ◽  
Vol 84 (6) ◽  
pp. 1435-1442 ◽  
Author(s):  
Claudia M. Muller ◽  
Annette Scierka ◽  
Richard L. Stiller ◽  
Yong-Myeong Kim ◽  
Ryan D. Cook ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Cytochrome P450 ◽  
Drug Metabolism ◽  
Sprague Dawley ◽  
Cytochrome P450 Content ◽  
Nitrate Concentrations ◽  
Hypnotic Drugs ◽  
Plasma Nitrite

Background Animals subjected to immunostimulatory conditions (sepsis) exhibit decreased total cytochrome P450 content and decreased P450-dependent drug metabolism. Cytochrome P450 function is of clinical significance because it mediates the metabolism of some opioid and hypnotic drugs. The authors tested the hypothesis that reduced P450 function and decreased drug metabolism in sepsis are mediated by endotoxin-enhanced synthesis of nitric oxide. Methods Hepatic microsomes were prepared from male Sprague-Dawley rats in nontreated rats, rats pretreated with phenobarbital and rats receiving aminoguanidine or NG-L-monomethyl-arginine alone. Nitric oxide synthesis was augmented for 12 h with a single injection of bacterial lipopolysaccharides. Nitric oxide synthase was inhibited with aminoguanidine or N(G)-L-monomethyl-arginine during the 12 h of endotoxemia in some animals. Plasma nitrite and nitrate concentrations were measured in vivo, and total microsomal P450 content, and metabolism of ethylmorphine and midazolam in vitro. Results Administration of endotoxin increased plasma nitrite and nitrate concentrations, decreased total cytochrome P450 content, and decreased metabolism of ethylmorphine and midazolam. Inhibition of nitric oxide formation by aminoguanidine or N(G)-L-monomethyl-arginine partially prevented the endotoxin-induced effects in the nontreated and phenobarbital-treated groups. Aminoguanidine or N(G)-L-monomethyl-arginine alone did not have an effect on either total cytochrome P450 content or P450-dependent drug metabolism. Plasma nitrite and nitrate concentrations correlated significantly negatively with P450 content (nontreated r = -0.88, phenobarbital r = -0.91), concentrations of formed formaldehyde (nontreated r = -0.87, phenobarbital r = -0.95), and concentrations of midazolam metabolites (4-OH midazolam nontreated r = -0.88, phenobarbital r = -0.93, and 1'-OH midazolam nontreated r = -0.88, phenobarbital r = -0.97). Conclusions Altered hepatic microsomal ethylmorphine and midazolam metabolism during sepsis is mediated in large part by nitric oxide.

Does Crizotinib Auto-Inhibit CYP3A in vivo?

Pharmacology ◽  
2020 ◽  
Vol 105 (11-12) ◽  
pp. 715-718
Author(s):  
Abigail R. Bland ◽  
Nensi Shrestha ◽  
Rhonda J. Rosengren ◽  
John C. Ashton
Keyword(s):  
Lung Cancer ◽  
Cytochrome P450 ◽  
Western Blot ◽  
Anaplastic Lymphoma Kinase ◽  
Kinase Inhibitor ◽  
Cyp3a Activity ◽  
Cytochrome P450 3A ◽  
Anaplastic Lymphoma

Crizotinib is a tyrosine kinase inhibitor used to treat anaplastic lymphoma kinase-positive lung cancer. There is in vitro evidence that crizotinib may auto-inhibit cytochrome P450 3A (CYP3A) activity, with important implications for crizotinib pharmacokinetics. In order to test whether crizotinib treatment alters CYP3A activity in vivo, mice were treated with 5 and 25 mg/kg crizotinib (p.o.) daily for 14 days. Results showed that crizotinib treatment did not alter CYP3A activity as determined by erythromycin <i>N</i>-demethylation. In addition, CYP3A polypeptide expression as measured by Western blot was unchanged. Therefore, our results do not support CYP3A inhibition by crizotinib in vivo.

scholarly journals Inhibitory Effect of Lygodium Root on the Cytochrome P450 3A Enzyme in vitro and in vivo

2020 ◽  
Vol Volume 14 ◽  
pp. 1909-1919
Author(s):  
Yunfang Zhou ◽  
Ailian Hua ◽  
Quan Zhou ◽  
Peiwu Geng ◽  
Feifei Chen ◽  
...  
Keyword(s):  
Cytochrome P450 ◽  
Inhibitory Effect ◽  
Cytochrome P450 3A
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