Cytochrome P450 Expression Research Articles

Effects of saikosaponin-d on CYP3A4 in HepaRG cell and protein-ligand docking study.

Saikosaponin-d (SSd) is a major bioactive triterpenoid saponin extracted from Bupleurum, which has anti-inflammatory, anticancer, antioxidative and anti-hepatic fibrosis effects. Due to the effects of Bupleurum-related formulations on cytochrome P450 (CYPs) expression still remain unclear, the combination therapies involved formulations containing Bupleurum may sometimes lead to unexpected drug-drug interactions in clinical practice. These interactions can limit the clinical applications of related formulations. In this study, we tried to explore the effects of SSd on CYP3A4 mRNA, protein expression and the enzyme activity in HepaRG cells by real-time quantitative reverse transcription polymerase chain reaction (RT-qPCR), Western blot (WB) and HPLC method, respectively. The interaction between SSd and CYP3A4 was analysed by molecular docking. HepaRG cells were cultured with different concentrations of SSd (0.5, 1, 5 and 10μmol/L) for 72hours. It is revealed that SSd can inhibit CYP3A4 mRNA and its protein expression, and also the enzyme activity. Moleculardockingstudy demonstrated that SSd can bind to several key active sites of amino acid residues of CYP3A4 protein with hydrogen bonds and hydrophobic interactions. Thus, drug-drug interactions resulted by SSd inhibiting CYP3A4 need attention when formulations containing SSd or Bupleurum are co-administrated with drugs metabolized by CYP3A4.

Interactive effects of Andrographis paniculata extracts and cancer chemotherapeutic 5-Fluorouracil on cytochrome P450s expression in human hepatocellular carcinoma HepG2 cells

Andrographis paniculata is an annual herbaceous plant widely used in many East Asian countries to help relieve symptoms of the common cold, fever, and non-infectious diarrhea. It is often co-administered with prescribed drugs. The present work aimed to study the interactive effects of A. paniculata extracts and the cancer chemotherapeutic drug, 5-Flurouracil (5-FU), on the expression of four common drug metabolizing cytochrome P450 s (CYP450), including CYP1A2, CYP3A4, CYP2C9, and CYP2D6, in human hepatocellular carcinoma HepG2 cells. Two different types of A. paniculata extracts were tested, the ethanolic extract at the first true leaf stage (FTLEE) and the water extract at the mature leaf stage (MLWE), along with their major phytochemical compound, andrographolide (AP1). The results showed that FTLEE, MLWE, and AP1 sensitized HepG2 cells to the cytotoxicity of 5-FU. Western Blotting assay demonstrated that both extracts and AP1 single treatments decreased CYP2C9 and CYP2D6 but increased CYP3A4 levels. 5-FU single treatment reduced the level of CYP1A2 and CYP2D6. Combination of 5-FU only with FTLEE produced an increase in CYP1A2 level compared to 5-FU treatment alone. Combination of either extracts or AP1 with 5-FU produced a further reduction of CYP2D6 levels. The data suggest the influence of harvesting stage of A. paniculata on CYP1A2 induction, and the synergistic effect of A. paniculata and 5-FU on CYP2D6 reduction. The combinations of A. paniculata with anti-cancer drugs should be critically considered. However, the interactive effects of A. paniculata extracts or AP1 with 5-FU on CYP450 s need more preclinical studies.

Genome-wide identification and expression profiling revealed tissue-specific inducible expression of cytochrome P450s conferring cadmium tolerance in the Pacific oyster, Crassostrea gigas

Cytochrome P450s (CYPs) are present in almost all organisms and play critical roles in metabolism of endogenous substrates and detoxification of xenobiotic compounds. Oysters are a group of bivalves that are important in marine ecosystem and aquaculture program, adapting to the harsh environment in intertidal zones. The studies on CYPs and their potential involvement in dealing with toxic xenobiotics in oysters were limited. In the present study, we performed a multiple omics analyses and identified a full-set of 123 CYP genes in the Pacific oyster, Crassostrea gigas. These CYP genes were classified into 5 clans and 16 families. The phylogenetic tree constructed with other species showed extensive gene expansion of CYPs in the clan 2 and mitochondrial clan in the C. gigas. The amino acid sequence analysis showed conserved typical motifs of CYP genes. The expression profiles of CYPs quantified across different tissues (gill and digestive gland) at various time points (0d, 0.5d, 7d, 14d, 28d) revealed their roles in response to Cd exposure. Notably, CYP17A1-like_6 and CYP2C50 were expressed at significantly higher levels compared with other CYP genes, suggesting their crucial roles in the detoxification of Cd in the C. gigas. This work provides valuable information toward understanding of CYP-mediated detoxification of cadmium in mollusks, and will be important for surveillance of marine environment pollution and seafood safety.

Detection of Caenorhabditis elegans Germ Cell Apoptosis Following Exposure to Environmental Contaminant Mixtures: A Crude Oil-Dispersant Mixture Example.

Crude oil disasters, such as the Deepwater Horizon accident, have caused severe environmental contamination and damage, affecting the health of marine and terrestrial organisms. Some previous studies have demonstrated cleanup efforts using chemical dispersant induced more potent toxicities than oil alone due to an increase in bioavailability of crude oil components, such as PAHs. However, there still lacks a systematic procedure that provides methods to determine genotypic and phenotypic changes following exposure to environmental toxicants or toxicant mixture, such as dispersed crude oil. Here, we describe methods for identifying a mechanism of dispersed crude oil-induced reproductive toxicity in the model organisms, Caenorhabditis elegans (C. elegans). Due to the genetic malleability of C. elegans, two mutant strains outlined in this chapter were used to identify a pathway responsible for inducing apoptosis: MD701 bcIs39 [lim-7p::ced-1::GFP+lin-15(+)], a mutant strain that allows visualization of apoptotic bodies via a green fluorescent protein fused to CED-1; and TJ1 (cep-1(gk138) I.), a p53/CEP-1 defective strain that is unable to activate apoptosis via the p53/CEP-1 pathway. In addition, qRT-PCR was utilized to demonstrate the aberrant expression of apoptosis (ced-13, ced-3, ced-4, ced-9, cep-1, dpl-1, efl-1, efl-2, egl-1, egl-38, lin-35, pax-2, and sir-2.1) and cytochrome P450 (cyp14a3, cyp35a1, cyp35a2, cyp35a5, and cyp35c1) protein-coding genes following exposure to dispersed crude oil. The procedure outlined here can be applicable to determine whether environmental contaminants, most of time contaminant mixture, cause reproductive toxicity by activation of the proapoptotic, p53/CEP-1 pathway.

Development and Validation of a Gliadin Induced Intestinal Enteropathy Rat Model of Non-Celiac Gluten Sensitivity

Background: Non-celiac gluten sensitivity (NCGS) is a syndrome that is related to the ingestion of gluten-containing food. In the current study we developed and validated a NCGS rat model. Materials and Methods: Wistar rats were divided into 2 groups: control group (receiving 0.02 M acetic acid solution) and gliadin group (receiving 1.5 mg/g of body weight of gliadin in acetic acid solution). Rats received its treatment by intra-gastric gavage on postnatal day 2, then three times a week for 6 weeks. Animals were assessed for weight changes, intestinal permeability, histology, inflammatory cytokines, and anti-gliadin antibodies (AGA). Intestinal permeability was evaluated 24 h prior to sacrifice by administering a lactulose/mannitol solution (500/250 mg/kg respectively), and collecting urine for 24 h. For histological examination, small intestines were collected, fixed, and stained with hematoxylin and eosin. Intestinal gene expression of cytochrome P450 (CYP 3a62, CYP 3a9/18) and uptake transporters, breast cancer resistance protein (ABCG2), and P-glycoprotein (MDR1a) were evaluated using qRT-PCR. Blood was collected for measurement of totalanti-gliadin antibodies (AGA), anti-gliadin immunoglobulins A and M (AGA-IgA and AGA-IgM), and pro-inflammatory cytokines. Results: As compared to control, the gliadin group had lower body weight, increased intestinal permeability (p<0.05); mild villous atrophy, increased intraepithelial lymphocytes, mild inflammation; increases in total AGA and AGA-IgM, increased gene expression of pro-inflammatory cytokines, IL-6, TNF-α, and IFN-γ, by 94%, 33%, and 46% (p < 0.05) and altered gene expressions of CYP450 and transporters. Conclusions: This model closely mimics the pathological and inflammatory characteristics of NCGS, and could be used to test new pharmacological treatments for this syndrome.

Primary hepatocytes isolated from human and porcine donors display similar patterns of cytochrome p450 expression following exposure to prototypical activators of AhR, CAR and PXR

The hepatic cytochrome p450’s (CYP) are of major importance for the metabolism of xenobiotics and knowledge about their regulation is crucial. This knowledge often originates from cell models; primary human hepatocytes (PHH) being the gold standard. However, due to limited availability of high-quality human donor organs, basic knowledge on alternative models are needed. Primary porcine hepatocytes (PPH) have been suggested as an alternative to PHH. Unfortunately, data comparing the response in gene-transcription to standard CYP inducers between PHH and PPH are missing. In the present study we, cultured PHH and PPH under the same conditions, treated them with standard inducers of the CYP1-3 and determined the response in gene and protein expression. The results demonstrated that in both species TCDD and omeprazole caused an increase in CYP1A/B expression. In PPH, CITCO increased the content of CYP1A/B. For the CYP2B/C/D’s, phenobarbital and rifampicin caused increases in expression. For the CYP2D’s, TCDD and omeprazole caused increased gene expression in PPH, which were not the case for PHH. Both phenobarbital, rifampicin and omeprazole increased CYP3A expression in PHH and PPH. Moreover, TCDD increased the gene expression of CYP3A in PPH; this was not the case for PHH. Multivariate data analysis found no difference in gene expression between PHH and PPH for phenobarbital, rifampicin and CITCO. However, differential clustering was observed for TCDD and omeprazole. In conclusion, despite model specificity, there are a high number of similar responses, and experiments investigating mRNA regulation made in PPH permits for a reliable translation into human setting.

Regulation of cytochrome P450 expression in oxidative stress-associated pathological conditions

Regulation of cytochrome P450 expression in oxidative stress-associated pathological conditions

Variation in the expression of cytochrome P450-related miRNAs and transcriptional factors in human livers: Correlation with cytochrome P450 gene phenotypes

Cytochrome P450 (CYP) gene expression exhibits large interindividual variation attributable to diverse regulatory factors including microRNAs (miRNAs) and hepatic transcription factors (TFs). We used real-time qPCR with 106 human liver samples to measure the expression and interindividual variation of seven miRNAs and four TFs that have been reported to regulate the expression of CYPs; we also identified factors that influence their expression. The results show that expression of the seven miRNAs and the four TFs exhibits a non-normal distribution and the expression variability is high (89- to 618-fold for miRNA and 12- to 85-fold for TFs). Age contributed to the interindividual variation for miR-148a, miR-27b and miR-34a, whereas cigarette smoking and alcohol consumption significantly reduced HNF4α mRNA levels. Association analysis showed significant correlations among the seven miRNAs as well as the four TFs. Furthermore, we systematically evaluated the impact of the seven miRNAs and four TFs on protein content, mRNA levels, translation efficiency and activity of 10 CYPs. The results show that numerous associations (positive and negative) are present between the seven miRNAs or the four TFs and the 10 CYP phenotypes (as indicated by mRNA, protein and activity); specifically, miR-27b, miR-34a and all four TFs played key roles in the interindividual variation of CYPs. Our results extend previous findings and suggest that miR-27b and miR-34a may be potential direct or indirect master regulators of CYP expression and thereby contribute to the interindividual variations in CYP-mediated drug metabolism.

Expression of cytochrome P450 isozyme transcripts and activities in human livers

Individual differences in cytochrome P450 (CYP) enzymes contribute to responses to drugs and environmental chemicals. The expression of CYPs is influenced by sex, age, and ethnicity. Human CYP studies are often conducted with human liver microsomes and liver cells to evaluate chemical induction and drug interactions. However, the basal or constitutive expression of CYP transcripts and enzyme activities in the intact liver are also important in our understanding of individual variation in CYPs. This study utilised 100 human liver samples to profile the constitutive expression of CYP1A2, 2B6, 2C8, 2C9, 2C19, 2D6, 2E1, 3A4, and 4A11 enzyme activity and transcript levels. The mRNA expression of the CYPs and xenobiotic receptors AhR, CAR, and PXR was examined via qPCR. Results showed that there was greater inter-individual variation in mRNA expression than in enzyme activities, except for CYP2C19. Females had higher CYP3A4 activity than males. Children had lower CYP4A14 activity, while elderly had lower P450 oxidoreductase activity. Compared to Caucasians, Hispanics had higher CYP2C8 activity and higher CYP2B6, CYP2C9, and CYP2C19 mRNA expression, whereas African Americans had lower CYP2D6 mRNA expression. These results add to our understanding of individual variations in xenobiotic metabolism and toxicology.

Assessment of Vedolizumab Disease-Drug-Drug Interaction Potential in Patients With Inflammatory Bowel Diseases.

Disease‐drug‐drug interactions (DDDIs) have been identified in some inflammatory diseases in which elevated proinflammatory cytokines can downregulate the expression of cytochrome P450 (CYP) enzymes, potentially increasing systemic exposure to drugs metabolized by CYPs. Following anti‐inflammatory treatments, CYP expression may return to normal, resulting in reduced drug exposure and diminished clinical efficacy. Vedolizumab has a well‐established positive benefit‐risk profile in patients with ulcerative colitis (UC) or Crohn's disease (CD) and has no known systemic immunosuppressive activity. A stepwise assessment was conducted to evaluate the DDDI potential of vedolizumab to impact exposure to drugs metabolized by CYP3A through cytokine modulation. First, a review of published data revealed that patients with UC or CD have elevated cytokine concentrations relative to healthy subjects; however, these concentrations remained below those reported to impact CYP expression. Exposure to drugs metabolized via CYP3A also appeared comparable between patients and healthy subjects. Second, serum samples from patients with UC or CD who received vedolizumab for 52 weeks were analyzed and compared with healthy subjects. Cytokine concentrations and the 4β‐hydroxycholesterol‐to‐cholesterol ratio, an endogenous CYP3A4 biomarker, were comparable between healthy subjects and patients both before and during vedolizumab treatment. Finally, a medical review of postmarketing DDDI cases related to vedolizumab from the past 6 years was conducted and did not show evidence of any true DDDIs. Our study demonstrated the lack of clinically meaningful effects of disease or vedolizumab treatment on the exposure to drugs metabolized via CYP3A through cytokine modulation in patients with UC or CD.

Cytochrome P450 Expression and Chemical Metabolic Activity before Full Liver Development in Zebrafish.

Zebrafish are used widely in biomedical, toxicological, and developmental research, but information on their xenobiotic metabolism is limited. Here, we characterized the expression of 14 xenobiotic cytochrome P450 (CYP) subtypes in whole embryos and larvae of zebrafish (4 to 144 h post-fertilization (hpf)) and the metabolic activities of several representative human CYP substrates. The 14 CYPs showed various changes in expression patterns during development. Many CYP transcripts abruptly increased at about 96 hpf, when the hepatic outgrowth progresses; however, the expression of some cyp1s (1b1, 1c1, 1c2, 1d1) and cyp2r1 peaked at 48 or 72 hpf, before full liver development. Whole-mount in situ hybridization revealed cyp2y3, 2r1, and 3a65 transcripts in larvae at 55 hpf after exposure to rifampicin, phenobarbital, or 2,3,7,8-tetrachlorodibenzo-p-dioxin from 30 hpf onward. Marked conversions of diclofenac to 4′-hydroxydiclofenac and 5-hydroxydiclofenac, and of caffeine to 1,7-dimethylxanthine, were detected as early as 24 or 50 hpf. The rate of metabolism to 4’-hydroxydiclofenac was more marked at 48 and 72 hpf than at 120 hpf, after the liver had become almost fully developed. These findings reveal the expression of various CYPs involved in chemical metabolism in developing zebrafish, even before full liver development.

Cytochrome P450 expression, induction and activity in human induced pluripotent stem cell-derived intestinal organoids and comparison with primary human intestinal epithelial cells and Caco-2 cells

Human intestinal organoids (HIOs) are a promising in vitro model consisting of different intestinal cell types with a 3D microarchitecture resembling native tissue. In the current study, we aimed to assess the expression of the most common intestinal CYP enzymes in a human induced pluripotent stem cell (hiPSC)-derived HIO model, and the suitability of that model to study chemical-induced changes in CYP expression and activity. We compared this model with the commonly used human colonic adenocarcinoma cell line Caco-2 and with a human primary intestinal epithelial cell (IEC)-based model, closely resembling in vivo tissue. We optimized an existing protocol to differentiate hiPSCs into HIOs and demonstrated that obtained HIOs contain a polarized epithelium with tight junctions consisting of enterocytes, goblet cells, enteroendocrine cells and Paneth cells. We extensively characterized the gene expression of CYPs and activity of CYP3A4/5, indicating relatively high gene expression levels of the most important intestinal CYP enzymes in HIOs compared to the other models. Furthermore, we showed that CYP1A1 and CYP1B1 were induced by β-naphtoflavone in all three models, whereas CYP3A4 was induced by phenobarbital and rifampicin in HIOs, in the IEC-based model (although not statistically significant), but not in Caco-2 cells. Interestingly, CYP2B6 expression was not induced in any of the models by the well-known liver CYP2B6 inducer phenobarbital. In conclusion, our study indicates that hiPSC-based HIOs are a useful in vitro intestinal model to study biotransformation of chemicals in the intestine.

First assessment of POPs and cytochrome P450 expression in Cuvier\u2019s beaked whales (Ziphius cavirostris) skin biopsies from the Mediterranean Sea

The Cuvier's beaked whale (Ziphius cavirostris) is one of the least known cetacean species worldwide. The decreasing population trend and associated threats has led to the IUCN categorising the Mediterranean subpopulation as Vulnerable on the Red List of Threatened Species. This study aimed to investigate for the first time the ecotoxicological status of Cuvier's beaked whale in the NW Mediterranean Sea. The study sampled around the 20% of the individuals belonging to the Ligurian subpopulation, collecting skin biopsies from free-ranging specimens. The levels of polychlorinated biphenyl (PCBs), polybrominated diphenyl ethers (PBDEs) and induction of cytochrome's P450 (CYP1A1 and CYP2B isoforms) were evaluated. Results highlighted that the pattern of concentration for the target contaminants was PCBs > PBDEs and the accumulation values were linked to age and sex, with adult males showing significantly higher levels than juvenile. Concerns raised by the fact that 80% of the individuals had PCB levels above the toxicity threshold for negative physiological effects in marine mammals. Therefore, these findings shed light on this silent and serious threat never assessed in the Mediterranean Cuvier’s beaked whale population, indicating that anthropogenic pressures, including chemical pollution, may represent menaces for the conservation of this species in the Mediterranean Sea.

Impact of ethylene glycol on DHEA dihydroxylation in Colletotrichum lini: Increasing the expression of cytochrome P450 and 6-phosphogluconate dehydrogenase and enhancing the generation of NADPH

3β,7α,15α-trihydroxy-5-androsten-17-one (7α,15α-diOH-DHEA), a key precursor of the novel oral contraceptive “Yasmin”, can be obtained by dihydroxylation in the 7α and 15α positions of dehydroepiandrosterone (DHEA) by Colletotrichum lini CGMCC 6051. However, the commercial-scale application of 7α,15α-diOH-DHEA is limited by the poor dihydroxylation efficiency and its low yield. This research investigated different organic solvents to improve the dihydroxylation efficiency of DHEA by C. lini CGMCC 6051. Results showed that ethylene glycol was the optimum organic solvent. With the addition of 0.5 % (v/v) ethylene glycol, the molar yield of 7α,15α-diOH-DHEA increased from 26.0%–79.4% at 12 g/L DHEA, and that of the intermediate product 7α−OH-DHEA decreased to 10.5 %. We then investigated the related functional mechanism of ethylene glycol on DHEA bioconversion. Results of two-dimensional electrophoresis proteomics analysis demonstrated that the expression levels of cytochrome P450 and 6-phosphogluconate dehydrogenase were increased upon the addition of ethylene glycol. Further studies suggested that ethylene glycol played critical roles in stabilizing the pH of the transformation system and generating co-enzyme NADPH during DHEA bioconversion. Hence, the addition of ethylene glycol induced the expression level of the key hydroxylase cytochrome P450 and increased the concentration of NADPH, which aided the dihydroxylation of DHEA in C. lini CGMCC6051.

Fenpropathrin resistance in Asian citrus psyllid, Diaphorina citri Kuwayama: risk assessment and changes in expression of CYP and GST genes associated with resistance

Asian citrus psyllid, Diaphorina citri Kuwayama (Hemiptera: Liviidae), populations exhibit varying levels of resistance to several insecticide classes, including pyrethroids. Artificial laboratory selection was conducted to investigate mechanisms underlying fenpropathrin resistance. After ten generations of selection, the LC50 for fenpropathrin increased from 0.18 to 11.60 ng/μL, and the associated resistance ratio increased by 96.67-fold. The realized heritability of resistance (h2 ) to fenpropathrin changed from 0.17 to 0.44 during the first and second round of selection, respectively. We did not find high cross-resistance to imidacloprid (RR = 3.58) or dimethoate (RR = 1.77) in the fenpropathrin-selected strain, but found cross-resistance to bifenthrin (RR = 28.21). RT-qPCR analysis showed that expression of CYP6A2-1 was significantly increased in the selected population relative to the laboratory susceptible population. Our data indicate that D. citri has the capacity to develop a high level of fenpropathrin resistance following persistent selection and that cytochrome P450 (CYP) and glutathione S-transferase (GST) metabolic detoxification may be contributing mechanisms. Rotation programs that include neonicotinoids and organophosphates should manage resistance to fenpropathrin for D. citri.

Benzopyrene induces oxidative stress and increases expression and activities of antioxidant enzymes, and CYP450 and GST metabolizing enzymes in Ulva lactuca (Chlorophyta).

Benzopyrene is rapidly incorporated and metabolized, and induces oxidative stress and activation of antioxidant enzymes, and CYP450 and GST metabolizing enzymes in Ulva lactuca. To analyze absorption and metabolism of benzo[a]pyrene (BaP) in Ulva lactuca, the alga was cultivated with 5µM of BaP for 72h. In the culture medium, BaP level rapidly decreased reaching a minimal level at 12h and, in the alga, BaP level increased until 6h, remained stable until 24h, and decreased until 72h indicating that BaP is being metabolized in U. lactuca. In addition, BaP induced an initial increase in hydrogen peroxide decreasing until 24h, superoxide anions level that remained high until 72h, and lipoperoxides that initially increased and decreased until 72h, showing that BaP induced oxidative stress. Activities of antioxidant enzymes superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (AP), glutathione reductase (GR) and glutathione peroxidase (GP) were increased, whereas dehydroascorbate reductase (DHAR) activity was unchanged. The level of transcripts encoding these antioxidant enzymes was increased, but transcripts encoding DHAR remained unchanged. Interestingly, the activity of glutathione-S-transferase (GST) was also increased, and inhibitors of cytochrome P450 (CYP450) and GST activities enhanced the level of BaP in algal tissue, suggesting that these enzymes participate in BaP metabolism.

Endocrine disrupting effects of binary mixtures of 17β-estradiol and testosterone in adult female western mosquitofish (Gambusia affinis)

Androgens and estrogens often co-exist in aquatic environments and pose potential risks to fish populations. However, little is known about the endocrine disrupting effects of the mixture of androgens and estrogens in fish. In this study, transcriptional level of target genes related to the hypothalamic-pituitary-gonadal-liver (HPGL) axis, sex hormone level, VTG protein concentration, histology and secondary sex characteristic were assessed in the ovaries and livers of adult female western mosquitofish (Gambusia affinis) exposed to 17β-estradiol (E2), testosterone (T), and mixtures of E2 and T for 91 days. The results showed that the transcriptional expression of cytochrome P450, family 19, subfamily A, polypeptide 1a (Cyp19a1a) was suppressed in the 200 ng/L T treatment and the 50 ng/L E2 + 200 ng/L T treatment in the ovaries. Steroidogenic acute regulatory protein (Star) and Cyp11a1 showed a similar expression pattern in the T treatment to its corresponding T + E2 mixtures. In the ovaries, the concentrations of 17β-estradiol and testosterone were decreased in most treatments compared with the solvent control. VTG protein was induced in all steroid treatment. However, exposure to T or E2 + T mixture did not cause the abnormal cells of the ovaries and livers and an extension of the anal fins in female G. affinis. This study demonstrates that chronic exposure to E2, T and their mixtures affects the transcripts of genes in the HPGL axis, steroid hormone level and VTG protein concentration in the ovaries and livers, but fails to cause the histopathological effect of the ovaries and livers and alter the morphology of the anal fins in G. affinis.

Cross-species analysis of hepatic cytochrome P450 and transport protein expression

Most drugs and xenobiotics are metabolized in the liver. Amongst others, different cytochrome P450 (CYP) enzymes catalyze the metabolic conversion of foreign compounds, and various transport proteins are engaged in the excretion of metabolites from the hepatocytes. Inter-species and inter-individual differences in the hepatic levels and activities of drug-metabolizing enzymes and transporters result from genetic as well as from environmental factors, and play a decisive role in determining the pharmacokinetic properties of a compound in a given test system. To allow for a meaningful comparison of results from metabolism studies, it is, therefore, of utmost importance to know about the specific metabolic properties of the test systems, especially about the levels of metabolic enzymes such as the CYPs. Using a targeted proteomics approach, we, therefore, compared the hepatic levels of important CYP enzymes and transporters in different experimental systems in vivo and in vitro, namely Wistar rats, C57/Bl6 mice, mice humanized for the two xeno-sensing receptors PXR (pregnane-X-receptor) and CAR (constitutive androstane receptor), mice with human hepatocyte-repopulated livers, human HepaRG hepatocarcinoma cells, primary human hepatocytes, and human liver biopsies. In addition, the effects of xenobiotic inducers of drug metabolism on CYP enzymes and transporters were analyzed in selected systems. This study for the first time presents a comprehensive overview of similarities and differences in important drug metabolism-related proteins among the different experimental models.

P.674 Chronic treatment with the atypical neuroleptic asenapine decreases the cytochrome P450 expression and activity in the liver

P.674 Chronic treatment with the atypical neuroleptic asenapine decreases the cytochrome P450 expression and activity in the liver

Safety and Molecular-Toxicological Implications of Cannabidiol-Rich Cannabis Extract and Methylsulfonylmethane Co-Administration.

Cannabidiol (CBD) is a biologically active, non-psychotropic component of Cannabis sativa whose popularity has grown exponentially in recent years. Besides a wealth of potential health benefits, ingestion of CBD poses risks for a number of side effects, of which hepatotoxicity and CBD/herb-drug interactions are of particular concern. Here, we investigated the interaction potential between the cannabidiol-rich cannabis extract (CRCE) and methylsulfonylmethane (MSM), a popular dietary supplement, in the mouse model. For this purpose, 8-week-old male C57BL6/J mice received MSM-containing water (80 mg/100 mL) ad libitum for 17 days. During the last three days of treatment, mice received three doses of CRCE administered in sesame oil via oral gavage (123 mg/kg/day). Administration of MSM alone did not result in any evidence of liver toxicity and did not induce expression of mouse cytochrome P450 (CYP) enzymes. Administration of CRCE did produce significant (p < 0.05) increases in Cyp1a2, Cyp2b10, Cyp2c29, Cyp3a4, Cyp3a11, Cyp2c65, and Cyp2c66 messenger RNA, however, this effect was not amplified by MSM/CRCE co-treatment. Similarly, no evidence of liver toxicity was observed in MSM/CRCE dosed mice. In conclusion, short-term MSM/CRCE co-administration did not demonstrate any evidence of hepatotoxicity in the mouse model.