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Poudel S, Huber AD, Chen T. Regulation of Nuclear Receptors PXR and CAR by Small Molecules and Signal Crosstalk: Roles in Drug Metabolism and Beyond. Drug Metab Dispos 2023; 51:228-236. [PMID: 36116789 PMCID: PMC9900866 DOI: 10.1124/dmd.122.000858] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2022] [Revised: 08/16/2022] [Accepted: 08/29/2022] [Indexed: 01/31/2023] Open
Abstract
Pregnane X receptor (PXR) and constitutive androstane receptor (CAR) are ligand-activated transcription factors that regulate the expression of drug metabolizing enzymes and drug transporters. Since their discoveries, they have been studied as important factors for regulating processes related to drug efficacy, drug toxicity, and drug-drug interactions. However, their vast ligand-binding profiles extend into additional spaces, such as endogenously produced chemicals, microbiome metabolites, dietary compounds, and environmental pollutants. Therefore, PXR and CAR can respond to an enormous abundance of stimuli, resulting in significant shifts in metabolic programs and physiologic homeostasis. Naturally, PXR and CAR have been implicated in various diseases related to homeostatic perturbations, such as inflammatory bowel disorders, diabetes, and certain cancers. Recent findings have injected the field with new signaling mechanisms and tools to dissect the complex PXR and CAR biology and have strengthened the potential for future PXR and CAR modulators in the clinic. Here, we describe the historical and ongoing importance of PXR and CAR in drug metabolism pathways and how this history has evolved into new mechanisms that regulate and are regulated by these xenobiotic receptors, with a specific focus on small molecule ligands. To effectively convey the impact of newly emerging research, we have arranged five diverse and representative key recent advances, four specific challenges, and four perspectives on future directions. SIGNIFICANCE STATEMENT: PXR and CAR are key transcription factors that regulate homeostatic detoxification of the liver and intestines. Diverse chemicals bind to these nuclear receptors, triggering their transcriptional tuning of the cellular metabolic response. This minireview revisits the importance of PXR and CAR in pharmaceutical drug responses and highlights recent results with implications beyond drug metabolism.
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Affiliation(s)
- Shyaron Poudel
- Department of Chemical Biology and Therapeutics, St. Jude Children's Research Hospital, Memphis, Tennessee
| | - Andrew D Huber
- Department of Chemical Biology and Therapeutics, St. Jude Children's Research Hospital, Memphis, Tennessee
| | - Taosheng Chen
- Department of Chemical Biology and Therapeutics, St. Jude Children's Research Hospital, Memphis, Tennessee
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Abstract
Hepatic drug metabolism is a major route of drug elimination, mediated by multiple drug-metabolizing enzymes. Any changes in the rate and extent of hepatic drug metabolism can lead to altered drug efficacy or toxicity. Accumulating clinical evidence indicates that pregnancy is accompanied by changes in hepatic drug metabolism. In this article, we discuss in vitro and in vivo tools used to study the mechanisms underlying the altered drug metabolism during pregnancy, focusing on primary hepatocyte culture, transgenic animal models, and use of probe drugs to assess change in enzymatic activity. The information obtained from these studies has enabled prediction of clinical PK changes for a given drug in pregnant women.
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Affiliation(s)
- Hyunyoung Jeong
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Illinois at Chicago, 900 S. Ashland Ave, Chicago, IL 60607, United States.
| | - Catherine S. Stika
- Department of Obstetrics and Gynecology, Northwestern University Feinberg School of Medicine, Chicago, IL
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Fanaei-Kahrani Z, Ganjalikhany MR, Rasa SMM, Emamzadeh R. New insights into the molecular characteristics behind the function of Renilla luciferase. J Cell Biochem 2017; 119:1780-1790. [PMID: 28796298 DOI: 10.1002/jcb.26339] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2017] [Accepted: 08/09/2017] [Indexed: 01/10/2023]
Abstract
Renilla Luciferase (RLuc) is a blue light emitter protein which can be applied as a valuable tool in medical diagnosis. But due to lack of the crystal structure of RLuc-ligand complex, the functional motions and catalytic mechanism of this enzyme remain largely unknown. In the present study, the active site properties and the ligand-receptor interactions of the native RLuc and its red-shifted light emitting variant (Super RLuc 8) were investigated using molecular docking approach, molecular dynamics (MD) analysis, and MM-PBSA method. The detailed analysis of the main clusters led to identifying a lid-like structure and its functional motions. Furthermore, an induced-fit mechanism is proposed where ligand-binding induces conformational changes of the active site. Our findings give an insight into the deeper understanding of RLuc conformational changes during binding steps and ligand-receptor pattern. Moreover, our work broaden our understanding of how active site geometry is adjusted to support the catalytic activity and red-shifted light emission in Super RLuc 8.
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Affiliation(s)
- Zahra Fanaei-Kahrani
- Department of Biology, Faculty of Sciences, University of Isfahan, Isfahan, Iran
| | | | | | - Rahman Emamzadeh
- Department of Biology, Faculty of Sciences, University of Isfahan, Isfahan, Iran
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Vyhlidal CA, Bi C, Ye SQ, Leeder JS. Dynamics of Cytosine Methylation in the Proximal Promoters of CYP3A4 and CYP3A7 in Pediatric and Prenatal Livers. Drug Metab Dispos 2016; 44:1020-6. [PMID: 26772622 DOI: 10.1124/dmd.115.068726] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2015] [Accepted: 01/14/2016] [Indexed: 11/22/2022] Open
Abstract
Members of the human CYP3A family of metabolizing enzymes exhibit developmental changes in expression whereby CYP3A7 is expressed in fetal tissues, followed by a transition to expression of CYP3A4 in the first months of life. Despite knowledge about the general pattern of CYP3A activity in human development, the mechanisms that regulate developmental expression remain poorly understood. Epigenetic changes, including cytosine methylation, have been suggested to play a role in the regulation of CYP3A expression. The objective of this study was to investigate changes in cytosine methylation of the CYP3A4 and CYP3A7 genes in human pediatric and prenatal livers. The methylation status of cytosine-phospho-guanine dinucleotides was determined in 16 pediatric liver samples using methyl-seq and confirmed by bisulfite sequencing of 48 pediatric and 34 prenatal liver samples. Samples were separated by age into five groups (prenatal, < 1 year of age, 1.8-6 years, 7-11 years, and 12-17 years). Methyl-seq anaylsis revealed that cytosines in the proximal promoter of CYP3A7 are hypomethylated in neonates compared with adolescents (P < 0.001). In contrast, a cytosine 383 base pair upstream of CYP3A4 is hypermethylated in liver samples from neonates compared with adolescents (P = 0.00001). Developmental changes in methylation of cytosines in the proximal promoters of CYP3A4 and CYP3A7 in pediatric livers were confirmed by bisulfite sequencing. In addition, the methylation status of cytosine in the CYP3A4 and CYP3A7 proximal promoters correlated with changes in developmental expression of mRNA for the two enzymes.
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Affiliation(s)
- Carrie A Vyhlidal
- Division of Clinical Pharmacology, Toxicology and Therapeutic Innovation (C.A.V., C.B., J.S.L.), and Division of Experimental and Translational Genetics (S.Q.Y.), Department of Pediatrics, Children's Mercy Hospital, Kansas City, Missouri
| | - Chengpeng Bi
- Division of Clinical Pharmacology, Toxicology and Therapeutic Innovation (C.A.V., C.B., J.S.L.), and Division of Experimental and Translational Genetics (S.Q.Y.), Department of Pediatrics, Children's Mercy Hospital, Kansas City, Missouri
| | - Shui Qing Ye
- Division of Clinical Pharmacology, Toxicology and Therapeutic Innovation (C.A.V., C.B., J.S.L.), and Division of Experimental and Translational Genetics (S.Q.Y.), Department of Pediatrics, Children's Mercy Hospital, Kansas City, Missouri
| | - J Steven Leeder
- Division of Clinical Pharmacology, Toxicology and Therapeutic Innovation (C.A.V., C.B., J.S.L.), and Division of Experimental and Translational Genetics (S.Q.Y.), Department of Pediatrics, Children's Mercy Hospital, Kansas City, Missouri
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Inagaki Y, Fujioka M, Kanzaki S, Watanabe K, Oishi N, Itakura G, Yasuda A, Shibata S, Nakamura M, Okano HJ, Okano H, Ogawa K. Sustained Effect of Hyaluronic Acid in Subcutaneous Administration to the Cochlear Spiral Ganglion. PLoS One 2016; 11:e0153957. [PMID: 27099926 PMCID: PMC4839654 DOI: 10.1371/journal.pone.0153957] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2015] [Accepted: 04/06/2016] [Indexed: 01/05/2023] Open
Abstract
The spatiotemporal distribution of drugs in the inner ear cannot be precisely evaluated because of its small area and complex structure. In the present study, we used hyaluronic acid (HA)-dispersed luciferin to image transgenic mice and to determine the effect of HA on controlled drug delivery to the cochlea. GFAP-luc mice, which express luciferase in cochlear spiral ganglion cells, were subcutaneously administered HA-luciferin (HA-sc) or luciferin dissolved in saline (NS-sc) or intraperitoneally administered luciferin dissolved in saline (NS-ip). The bioluminescence of luciferin was monitored in vivo in real time. The peak time and half-life of fluorescence emission were significantly increased in HA-sc-treated mice compared with those in NS-sc- and NS-ip-treated mice; however, significant differences were not observed in peak photon counts. We detected differences in the pharmacokinetics of luciferin in the inner ear, including its sustained release, in the presence of HA. The results indicate the clinical potential of using HA for controlled drug delivery to the cochlea.
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Affiliation(s)
- Yozo Inagaki
- Department of Otolaryngology Head and Neck Surgery, Keio University, Shinjuku-ku, Tokyo, Japan
| | - Masato Fujioka
- Department of Otolaryngology Head and Neck Surgery, Keio University, Shinjuku-ku, Tokyo, Japan
| | - Sho Kanzaki
- Department of Otolaryngology Head and Neck Surgery, Keio University, Shinjuku-ku, Tokyo, Japan
- * E-mail:
| | - Kotaro Watanabe
- Department of Otolaryngology Head and Neck Surgery, Keio University, Shinjuku-ku, Tokyo, Japan
| | - Naoki Oishi
- Department of Otolaryngology Head and Neck Surgery, Keio University, Shinjuku-ku, Tokyo, Japan
| | - Go Itakura
- Department of Orthopedics, School of Medicine, Keio University, Shinjuku-ku, Tokyo, Japan
| | - Akimasa Yasuda
- Department of Orthopedics, School of Medicine, Keio University, Shinjuku-ku, Tokyo, Japan
| | - Shinsuke Shibata
- Department of Physiology, School of Medicine, Keio University, Shinjuku-ku, Tokyo, Japan
| | - Masaya Nakamura
- Department of Orthopedics, School of Medicine, Keio University, Shinjuku-ku, Tokyo, Japan
| | - Hirotaka James Okano
- Department of Physiology, School of Medicine, Keio University, Shinjuku-ku, Tokyo, Japan
| | - Hideyuki Okano
- Department of Physiology, School of Medicine, Keio University, Shinjuku-ku, Tokyo, Japan
| | - Kaoru Ogawa
- Department of Otolaryngology Head and Neck Surgery, Keio University, Shinjuku-ku, Tokyo, Japan
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Tsuji S, Kawamura F, Kubiura M, Hayashi A, Ohbayashi T, Kazuki Y, Chesné C, Oshimura M, Tada M. Dual-color fluorescence imaging to monitor CYP3A4 and CYP3A7 expression in human hepatic carcinoma HepG2 and HepaRG cells. PLoS One 2014; 9:e104123. [PMID: 25101946 PMCID: PMC4125183 DOI: 10.1371/journal.pone.0104123] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2013] [Accepted: 07/11/2014] [Indexed: 12/31/2022] Open
Abstract
Human adult hepatocytes expressing CYP3A4, a major cytochrome P450 enzyme, are required for cell-based assays to evaluate the potential risk of drug-drug interactions caused by transcriptional induction of P450 enzymes in early-phase drug discovery and development. However, CYP3A7 is preferentially expressed in premature hepatoblasts and major hepatic carcinoma cell lines. The human hepatocellular carcinoma cell line HepaRG possesses a high self-renewal capacity and can differentiate into hepatic cells similar to human adult hepatocytes in vitro. Transgenic HepaRG cells, in which the expression of fluorescent reporters is regulated by 35 kb regulatory elements of CYP3A4, have a distinct advantage over human hepatocytes isolated by collagenase perfusion, which are unstable in culture. Thus, we created transgenic HepaRG and HepG2 cells by replacing the protein-coding regions of human CYP3A4 and CYP3A7 with enhanced green fluorescent protein (EGFP) and DsRed reporters, respectively, in a bacterial artificial chromosome vector that included whole regulatory elements. The intensity of DsRed fluorescence was initially high during the proliferation of transgenic HepaRG cells. However, most EGFP-positive cells were derived from those in which DsRed fluorescence was extinguished. Comparative analyses in these transgenic clones showed that changes in the total fluorescence intensity of EGFP reflected fold changes in the mRNA level of endogenous CYP3A4. Moreover, CYP3A4 induction was monitored by the increase in EGFP fluorescence. Thus, this assay provides a real-time evaluation system for quality assurance of hepatic differentiation into CYP3A4-expressing cells, unfavourable CYP3A4 induction, and fluorescence-activated cell sorting-mediated enrichment of CYP3A4-expressing hepatocytes based on the total fluorescence intensities of fluorescent reporters, without the need for many time-consuming steps.
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Affiliation(s)
- Saori Tsuji
- Bio Frontier Project Promotion Section, Organization for Tottori Industrial Promotion, Yonago, Japan
| | - Fumihiko Kawamura
- Division of Molecular Genetics and Biofunction, Department of Biomedical Science, Institute of Regenerative Medicine and Biofunction, Graduate School of Medical Science, Tottori University, Yonago, Japan
| | - Musashi Kubiura
- Division of Molecular Genetics and Biofunction, Department of Biomedical Science, Institute of Regenerative Medicine and Biofunction, Graduate School of Medical Science, Tottori University, Yonago, Japan
| | - Ayaka Hayashi
- Division of Molecular Genetics and Biofunction, Department of Biomedical Science, Institute of Regenerative Medicine and Biofunction, Graduate School of Medical Science, Tottori University, Yonago, Japan
| | - Tetsuya Ohbayashi
- Division of Laboratory Animal Science, Research Center for Bioscience and Technology, Tottori University, Yonago, Japan
| | - Yasuhiro Kazuki
- Division of Molecular Genetics and Biofunction, Department of Biomedical Science, Institute of Regenerative Medicine and Biofunction, Graduate School of Medical Science, Tottori University, Yonago, Japan
- Chromosome Engineering Research Center, Tottori University, Yonago, Japan
| | | | - Mitsuo Oshimura
- Chromosome Engineering Research Center, Tottori University, Yonago, Japan
| | - Masako Tada
- Chromosome Engineering Research Center, Tottori University, Yonago, Japan
- * E-mail:
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New researches and application progress of commonly used optical molecular imaging technology. BIOMED RESEARCH INTERNATIONAL 2014; 2014:429198. [PMID: 24696850 PMCID: PMC3947735 DOI: 10.1155/2014/429198] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/27/2013] [Accepted: 12/20/2013] [Indexed: 12/26/2022]
Abstract
Optical molecular imaging, a new medical imaging technique, is developed based on genomics, proteomics and modern optical imaging technique, characterized by non-invasiveness, non-radiativity, high cost-effectiveness, high resolution, high sensitivity and simple operation in comparison with conventional imaging modalities. Currently, it has become one of the most widely used molecular imaging techniques and has been applied in gene expression regulation and activity detection, biological development and cytological detection, drug research and development, pathogenesis research, pharmaceutical effect evaluation and therapeutic effect evaluation, and so forth, This paper will review the latest researches and application progresses of commonly used optical molecular imaging techniques such as bioluminescence imaging and fluorescence molecular imaging.
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Henderson CJ, Scheer N, Wolf CR. Advances in the generation of mouse models to elucidate the pathways of drug metabolism in rodents and man. Expert Rev Clin Pharmacol 2014; 2:105-9. [DOI: 10.1586/17512433.2.2.105] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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9
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Chemical profiling of deoxyhypusine hydroxylase inhibitors for antimalarial therapy. Amino Acids 2013; 45:1047-53. [PMID: 23943044 DOI: 10.1007/s00726-013-1575-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2013] [Accepted: 08/02/2013] [Indexed: 02/07/2023]
Abstract
A first approach to discover new antimalarials has been recently performed in a combined approach with data from GlaxoSmithKline Tres Cantos Antimalarial Set, Novartis-GNF Malaria Box Data set and St. Jude Children's Research Hospital. These data are assembled in the Malaria Box. In a first phenotypic forward chemical genetic approach, 400 chemicals were employed to eradicate the parasite in the erythrocytic stages. The advantage of phenotypic screens for the identification of novel chemotypes is that no a priori assumptions are made concerning a fixed target and that active compounds inherently have cellular bioavailability. In a first screen 40 mostly heterocyclic, highly active compounds (in nmol range of growth inhibition) were identified with EC50 values ≤2 μM against chloroquine-resistant Plasmodium falciparum strains and a therapeutic window ≥10 against two mammalian cell lines. 78 % of the compounds had no violations with the Lipinski Rule of 5 and only 1 % of the compounds showed cytotoxicity when applied at concentrations of 10 μM. This pre-selective step of parasitic eradication will be used further for a test of the Malaria Box with a potential in iron chelating capacity to inhibit deoxyhypusine hydroxylase (DOHH) from P. falciparum and vivax. DOHH, a metalloprotein which consists of ferrous iron and catalyzes the second step of the posttranslational modification at a specific lysine in eukaryotic initiation factor 5A (EIF-5A) to hypusine. Hypusine is a novel, non-proteinogenic amino acid, which is essential in eukaryotes and for parasitic proliferation. DOHH seems to be a "druggable" target, since it has only 26 % amino acid identity to its human orthologue. For a High-throughput Screening (HTS) of DOOH inhibitors, rapid and robust analytical tools are a prerequisite. A proteomic platform for the detection of hypusine metabolites is currently established. Ultra performance Liquid Chromatography enables the detection of hypusine metabolites with retention times of 7.4 min for deoxyhypusine and 7.3 min for hypusine. Alternatively, the analytes can be detected by their masses with gas chromatography/mass spectrometry or one-dimensional chromatography coupled to mass spectrometry. Moreover, the identified hits will be tracked further to test their efficacy in novel "in vitro assays". Subsequently in vivo inhibition in a humanized mouse model will be tested.
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Dressler H, Economides K, Favara S, Wu NN, Pang Z, Polites HG. The CRE luc bioluminescence transgenic mouse model for detecting ligand activation of GPCRs. ACTA ACUST UNITED AC 2013; 19:232-41. [PMID: 23896687 DOI: 10.1177/1087057113496465] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Numerous assays have been developed to investigate the interactions between G-protein-coupled receptors (GPCRs) and their ligands since GPCRs are key therapeutic targets. Reporter-based assays using the cAMP response element (CRE) coupled with bioluminescence from a luciferase reporter have been used extensively in vitro with high-throughput screens (HTS) of large chemical compound libraries. We have generated a transgenic mouse model (CRE luc) with a luciferase reporter under the control of a synthetic promoter that contains several CREs, which supports real-time bioimaging of GPCR ligand activity in whole animals, tissues, or primary cells. In the CRE luc model, GPCR signaling through the cAMP pathway can be detected from the target GPCR that is in a native cellular environment with a full complement of associated receptors and membrane constituents. Multiple independent lines have been produced by random integration of the transgene, resulting in tissue expression profiles covering the major organs. The goal of the CRE luc model is to accelerate the transition from HTS to profiling of GPCR small-molecule leads in preclinical animal disease models, as well as define the mechanism of action of GPCR drugs in three experimental formats: primary cells, tissue homogenates, and whole animals.
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11
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Papageorgiou I, Grepper S, Unadkat JD. Induction of hepatic CYP3A enzymes by pregnancy-related hormones: studies in human hepatocytes and hepatic cell lines. Drug Metab Dispos 2013; 41:281-90. [PMID: 23223499 DOI: 10.1124/dmd.112.049015] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/13/2025] Open
Abstract
CYP3A activity is induced by approximately 2-fold during the third trimester of human pregnancy. Placental growth hormone (PGH), estrogens (primarily 17β-estradiol), cortisol, and progesterone have the potential to modulate CYP3A activity. Therefore, we determined whether the elevated plasma concentrations of these hormones during pregnancy induce hepatic CYP3A expression. We incubated sandwich-cultured human hepatocytes (SCHH) from premenopausal female donors (n = 2) with the physiologic (unbound, 1× total) and the 10× total third trimester hormone plasma concentrations (individually and in combination) and determined their effect on CYP3A activity and the transcripts of CYP3A4, CYP3A5, and the respective hormone receptors (growth hormone receptor, glucocorticoid receptor, and estrogen receptor alpha). Of all the hormones, cortisol was the most potent inducer of CYP3A activity and CYP3A4, CYP3A5 mRNA expression. The combination of PGH/growth hormone and cortisol induced CYP3A activity and expression significantly more than did cortisol alone. When incubated with the unbound or total plasma concentration of all the hormones, CYP3A activity in SCHH was induced to an extent comparable to that observed in vivo during the third trimester. These hormones had only a modest effect on the mRNA expression of the hormone receptors. The pattern of induction observed in SCHH was reproduced in HepaRG cells but not in HuH7/HepG2 cells. SCHH or HepaRG cells could be used to determine the mechanistic basis of CYP3A induction during pregnancy and to predict the magnitude of induction likely to be observed during the first and second trimesters, when phenotyping studies to measure in vivo CYP3A activity are logistically difficult to perform.
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Affiliation(s)
- Ioannis Papageorgiou
- Department of Pharmaceutics, School of Pharmacy, University of Washington, Seattle, WA 98195-7610, USA
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12
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Visualizing the location and the dynamics of gene expression in living animals through bioluminescence imaging. Methods Cell Biol 2013. [PMID: 23317896 DOI: 10.1016/b978-0-12-407239-8.00002-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
Abstract
Bioluminescence imaging allows for real-time assessment of gene expression in vivo in models where luciferase expression is controlled by promoter elements of gene of interest. It provides a sensitive means of recording temporal and spatial resolution of gene expression. In this Chapter, protocols for the use of the bioluminescence imaging system in localizing and semi-quantitatively measuring gene expression in mice are discussed.
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Abstract
Luciferase based assays have become an invaluable tool for the analysis of cloned promoter DNA fragments, both for verifying the ability of a potential promoter fragment to drive the expression of a luciferase reporter gene in various cellular contexts, and for dissecting binding elements in the promoter. Here, we describe the use of the Dual-Luciferase(®) Reporter Assay System created by Promega (Promega Corporation, Wisconsin, USA) to study the cloned 6.7 kilobases (kb) mouse (m) Tcf3 promoter DNA fragment in mouse embryonic derived neural stem cells (NSC). In this system, the expression of the firefly luciferase driven by the cloned mTcf3 promoter DNA fragment (including transcription initiation sites) is correlated with a co-transfected control reporter expressing Renilla luciferase from the herpes simplex virus (HSV) thymidine kinase promoter. Using an internal control reporter allows to normalize the activity of the experimental reporter to the internal control, which minimizes experimental variability.
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Affiliation(s)
- Nina Solberg
- Unit for Cell Signaling, Oslo University Hospital, Oslo, Norway
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Qiao J, Hong T, Triana TS, Guo H, Chung DH, Xu YQ. Magneto-Fluorescent Carbon Nanotube-Mediated siRNA for Gastrin-Releasing Peptide Receptor Silencing in Neuroblastoma. RSC Adv 2013; 3:4544-4551. [PMID: 25657845 DOI: 10.1039/c3ra23023f] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
We demonstrate a newly-developed magneto-fluorescent carbon nanotube (CNT) mediated siRNA (CNT-siRNA) delivery system, which significantly silences our target of interest, gastrin-releasing peptide receptor (GRP-R), in neuroblastoma. CNT-siGRP-R resulted in a 50% silencing efficiency and a sustained efficacy of 9 days for one-time siRNA treatment in vitro, whereas siRNA delivered by the commercial transfection reagent couldn't knockdown GRP-R expression. We further show that CNT-siRNA efficiently inhibits the growth of subcutaneous xenograft tumors in vivo. This system allows us to track the CNT-siRNA distribution via both near-infrared fluorescence and magnetic resonance imaging. Moreover, our delivery system can be used to knockdown GRP-R expression in other cancer cell types, such as human breast cancer cells. The high efficiency and sustained efficacy may indicate that the natural stacking interactions between CNTs and siRNAs can protect siRNAs from degradation and enhance their stability during the delivery process.
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Affiliation(s)
- Jingbo Qiao
- Department of Pediatric Surgery, Vanderbilt University Medical Center, Nashville, TN 37232
| | - Tu Hong
- Department of Electrical Engineering and Computer Science, Vanderbilt University, Nashville, TN 37235
| | - Taylor S Triana
- Department of Pediatric Surgery, Vanderbilt University Medical Center, Nashville, TN 37232
| | - Honglian Guo
- Department of Electrical Engineering and Computer Science, Vanderbilt University, Nashville, TN 37235
| | - Dai H Chung
- Department of Pediatric Surgery, Vanderbilt University Medical Center, Nashville, TN 37232 ; Department of Cancer Biology, Vanderbilt University Medical Center, Nashville, TN 37232
| | - Ya-Qiong Xu
- Department of Electrical Engineering and Computer Science, Vanderbilt University, Nashville, TN 37235 ; Department of Physics and Astronomy, Vanderbilt University, Nashville, TN 37235
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15
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Kazuki Y, Kobayashi K, Aueviriyavit S, Oshima T, Kuroiwa Y, Tsukazaki Y, Senda N, Kawakami H, Ohtsuki S, Abe S, Takiguchi M, Hoshiya H, Kajitani N, Takehara S, Kubo K, Terasaki T, Chiba K, Tomizuka K, Oshimura M. Trans-chromosomic mice containing a human CYP3A cluster for prediction of xenobiotic metabolism in humans. Hum Mol Genet 2012; 22:578-92. [PMID: 23125282 DOI: 10.1093/hmg/dds468] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Human CYP3A is the most abundant P450 isozyme present in the human liver and small intestine, and metabolizes around 50% of medical drugs on the market. The human CYP3A subfamily comprises four members (CYP3A4, CYP3A5, CYP3A7, CYP3A43) encoded on human chromosome 7. However, transgenic mouse lines carrying the entire human CYP3A cluster have not been constructed because of limitations in conventional cloning techniques. Here, we show that the introduction of a human artificial chromosome (HAC) containing the entire genomic human CYP3A locus recapitulates tissue- and stage-specific expression of human CYP3A genes and xenobiotic metabolism in mice. About 700 kb of the entire CYP3A genomic segment was cloned into a HAC (CYP3A-HAC), and trans-chromosomic (Tc) mice carrying a single copy of germline-transmittable CYP3A-HAC were generated via a chromosome-engineering technique. The tissue- and stage-specific expression profiles of CYP3A genes were consistent with those seen in humans. We further generated mice carrying the CYP3A-HAC in the background homozygous for targeted deletion of most endogenous Cyp3a genes. In this mouse strain with 'fully humanized' CYP3A genes, the kinetics of triazolam metabolism, CYP3A-mediated mechanism-based inactivation effects and formation of fetal-specific metabolites of dehydroepiandrosterone observed in humans were well reproduced. Thus, these mice are likely to be valuable in evaluating novel drugs metabolized by CYP3A enzymes and in studying the regulation of human CYP3A gene expression. Furthermore, this system can also be used for generating Tc mice carrying other human metabolic genes.
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Affiliation(s)
- Yasuhiro Kazuki
- Department of Biomedical Science, Institute of Regenerative Medicine and Biofunction, Graduate School of Medical Science, Tottori University, 86 Nishi-cho, Yonago, Tottori 683-8503, Japan
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16
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Roncoroni C, Rizzi N, Brunialti E, Cali JJ, Klaubert DH, Maggi A, Ciana P. Molecular imaging of cytochrome P450 activity in mice. Pharmacol Res 2012; 65:531-6. [PMID: 22391453 DOI: 10.1016/j.phrs.2012.02.006] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/02/2011] [Revised: 02/17/2012] [Accepted: 02/17/2012] [Indexed: 12/12/2022]
Abstract
Detailed knowledge of drug metabolism is relevant information provided by preclinical drug development research. Oxidative enzymes such as those belonging to P450 family of cytochromes (CYP) play a prominent role in drug metabolism. Here, we propose an innovative method based on bioluminescence in vivo imaging which has the potential to simplify the in vivo measurement of CYP activity also providing a dynamic measure of the effects of a drug on a specific P450 enzyme complex in a living mouse. The method is based on a pro-luciferin which can be converted into the active luciferase substrate by a specific P450 activity. The pro-luciferin is administered to a luciferase reporter mouse which produces luminescent signals in relation to the cytochrome activity present in each tissue. The photon emission generated can be easily localized and quantified by optical imaging. To demonstrate the validity of the system, we pharmacologically induced hepatic Cyp3a in the reporter mouse and proved that pro-luciferin administration generates a Cyp3a selective signal in the chest area that can be efficiently detected by optical imaging. The kind of tool generated has the potential to be exploited for the study of additional CYPs.
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Affiliation(s)
- Chiara Roncoroni
- Top (Transgenic Operative Products) Srl, via Einstein, 26900 Lodi, Italy
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Li C, Luo L, Awerman J, McGrath P. Whole Zebrafish Cytochrome P450 Assay for Assessing Drug Metabolism and Safety. Zebrafish 2011. [DOI: 10.1002/9781118102138.ch9] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
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18
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Sevior DK, Pelkonen O, Ahokas JT. Hepatocytes: the powerhouse of biotransformation. Int J Biochem Cell Biol 2011; 44:257-61. [PMID: 22123318 DOI: 10.1016/j.biocel.2011.11.011] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2010] [Revised: 10/12/2011] [Accepted: 11/14/2011] [Indexed: 01/10/2023]
Abstract
Liver is the most important organ involved in biotransformation of xenobiotics. Within the main organisational unit, the hepatocyte, is an assembly of enzymes commonly classified as phase I and phase II enzymes. The phase I enzymes principally cytochrome P450 catalyse both oxidative and reductive reactions of a bewildering number of xenobiotics. Many of the products of phase I enzymes become substrates for the phase II enzymes, which catalyse conjugation reactions making use of endogenous cofactors. As xenobiotic metabolising enzymes are responsible for the toxicity of many chemicals and drugs, testing the role of the biotransformation enzymes and the transporters within the hepatocyte is critical. New methodologies may be able to provide information to allow for better in vitro to in vivo extrapolation of data.
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Cheng J, Ma X, Gonzalez FJ. Pregnane X receptor- and CYP3A4-humanized mouse models and their applications. Br J Pharmacol 2011; 163:461-8. [PMID: 21091656 DOI: 10.1111/j.1476-5381.2010.01129.x] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Pregnane X receptor (PXR) is a pivotal nuclear receptor modulating xenobiotic metabolism primarily through its regulation of CYP3A4, the most important enzyme involved in drug metabolism in humans. Due to the marked species differences in ligand recognition by PXR, PXR-humanized (hPXR) mice, and mice expressing human PXR and CYP3A4 (Tg3A4/hPXR) were established. hPXR and Tg3A4/hPXR mice are valuable models for investigating the role of PXR in xenobiotic metabolism and toxicity, in lipid, bile acid and steroid hormone homeostasis, and in the control of inflammation.
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Affiliation(s)
- Jie Cheng
- Laboratory of Metabolism, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA
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Nissim L, Bar-Ziv RH. A tunable dual-promoter integrator for targeting of cancer cells. Mol Syst Biol 2011; 6:444. [PMID: 21179016 PMCID: PMC3018173 DOI: 10.1038/msb.2010.99] [Citation(s) in RCA: 105] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2010] [Accepted: 10/25/2010] [Indexed: 12/12/2022] Open
Abstract
Precise discrimination between similar cellular states is essential for autonomous decision-making scenarios, such as in vivo targeting of diseased cells. Discrimination could be achieved by delivering an effector gene expressed under a highly active context-specific promoter. Yet, a single-promoter approach has linear response and offers limited control of specificity and efficacy. Here, we constructed a dual-promoter integrator, which expresses an effector gene only when the combined activity of two internal input promoters is high. A tunable response provides flexibility in choosing promoter inputs and effector gene output. Experiments using one premalignant and four cancer cell lines, over a wide range of promoter activities, revealed a digital-like response of input amplification following a sharp activation threshold. The response function is cell dependent with its overall magnitude increasing with degree of malignancy. The tunable digital-like response provides robustness, acts to remove input noise minimizing false-positive identification of cell states, and improves targeting precision and efficacy.
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Affiliation(s)
- Lior Nissim
- Department of Materials and Interfaces, The Weizmann Institute of Science, Rehovot, Israel
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21
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Giannoni P, Scaglione S, Daga A, Ilengo C, Cilli M, Quarto R. Short-time survival and engraftment of bone marrow stromal cells in an ectopic model of bone regeneration. Tissue Eng Part A 2010; 16:489-99. [PMID: 19712045 DOI: 10.1089/ten.tea.2009.0041] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
In tissue-engineered applications bone marrow stromal cells (BMSCs) are combined with scaffolds to target bone regeneration; animal models have been devised and the cells' long-term engraftment has been widely studied. However, in regenerated bone, the cell number is severely reduced with respect to the initially seeded BMSCs. This reflects the natural low cellularity of bone but underlines the selectivity of the differentiation processes. In this respect, we evaluated the short-term survival of BMSCs, transduced with the luciferase gene, after implantation of cell-seeded scaffolds in a nude mouse model. Cell proliferation/survival was assessed by bioluminescence imaging: light production was decreased by 30% on the first day, reaching a 50% loss within 48 h. Less than 5% of the initial signal remained after 2 months in vivo. Apoptotic BMSCs were detected within the first 2 days of implantation. Interestingly, the initial frequency of clonogenic progenitors matched the percentage of in vivo surviving cells. Cytokines and inflammation may contribute to the apoptotic onset at the implant milieu. However, preculturing cells with tumor necrosis factor alpha enhanced survival, allowing detection of 8.1% of the seeded BMSCs 2 months after implantation. Thus culturing conditions may reduce the apoptotic overload of seeded osteoprogenitors, strengthening the constructs' osteogenic potential.
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Affiliation(s)
- Paolo Giannoni
- Stem Cell Laboratory, Advanced Biotechnology Center, Genova, Italy.
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Ma X, Cheung C, Krausz KW, Shah YM, Wang T, Idle JR, Gonzalez FJ. A double transgenic mouse model expressing human pregnane X receptor and cytochrome P450 3A4. Drug Metab Dispos 2008; 36:2506-12. [PMID: 18799805 PMCID: PMC2678901 DOI: 10.1124/dmd.108.022723] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Cytochrome P450 3A4 (CYP3A4), the most abundant human cytochrome P450 in liver, participates in the metabolism of approximately 50% of clinically used drugs. The pregnane X receptor (PXR), a member of the nuclear receptor superfamily, is the major activator of CYP3A4 transcription. However, because of species differences in response to PXR ligands, it is problematic to use rodents to assess CYP3A4 regulation and function. The generation of double transgenic mice expressing human PXR and CYP3A4 (TgCYP3A4/hPXR) would provide a solution to this problem. In the current study, a TgCYP3A4/hPXR mouse model was generated by bacterial artificial chromosome transgenesis in Pxr-null mice. In TgCYP3A4/hPXR mice, CYP3A4 was strongly induced by rifampicin, a human-specific PXR ligand, but not by pregnenolone 16alpha-carbonitrile, a rodent-specific PXR ligand. Consistent with CYP3A expression, hepatic CYP3A activity increased approximately 5-fold in TgCYP3A4/hPXR mice pretreated with rifampicin. Most antihuman immunodeficiency virus protease inhibitors are CYP3A substrates and their interactions with rifamycins are a source of major concern in patients coinfected with human immunodeficiency virus and Mycobacterium tuberculosis. By using TgCYP3A4/hPXR mice, human PXR-CYP3A4-mediated rifampicin-protease inhibitor interactions were recapitulated, as the metabolic stability of amprenavir, nelfinavir, and saquinavir decreased 52, 53, and 99%, respectively, in the liver microsomes of TgCYP3A4/hPXR mice pretreated with rifampicin. In vivo, rifampicin pretreatment resulted in an approximately 80% decrease in the area under the serum amprenavir concentration-time curve in TgCYP3A4/hPXR mice. These results suggest that the TgCYP3A4/hPXR mouse model could serve as a useful tool for studies on CYP3A4 transcription and function in vivo.
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Affiliation(s)
- Xiaochao Ma
- Laboratory of Metabolism, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, USA
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23
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Inoue T, Nitta K, Sugihara K, Horie T, Kitamura S, Ohta S. CYP2C9-catalyzed metabolism of S-warfarin to 7-hydroxywarfarin in vivo and in vitro in chimeric mice with humanized liver. Drug Metab Dispos 2008; 36:2429-33. [PMID: 18784266 DOI: 10.1124/dmd.108.022830] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
Chimeric mice having humanized livers were constructed by transplantation of human hepatocytes. In this study, we investigated whether these mice have a capacity for drug metabolism similar to that of humans by examining hydroxylation of S-warfarin, which is predominantly metabolized to S-7-hydroxywarfarin, catalyzed by CYP2C9, in humans but not mice. The 7-hydroxylating activity of chimeric mouse liver microsomes toward S-warfarin was approximately 10-fold higher than that of control (urokinase-type plasminogen activator-transgenic severe combined immunodeficient) mice. The 7-hydroxylase activity of chimeric mouse liver microsomes was markedly inhibited by sulfaphenazole, as was that of human liver microsomes, whereas the activity of control mice was unaffected. The CYP2C isoform in chimeric mouse liver was also confirmed to be the human isoform, CYP2C9, by immunoblot analysis. In the present in vivo study, the level of S-7-hydroxywarfarin in plasma of chimeric mice was approximately 7-fold higher than that in control mice, in agreement with the in vitro data. Thus, the CYP2C isoform in chimeric mice functions in vivo and in vitro as a human isoform, CYP2C9. These results suggest that chimeric mice with humanized liver could be useful for predicting drug metabolism in humans, at least regarding CYP2C9-dependent metabolism.
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Affiliation(s)
- Tae Inoue
- Graduate School of Biomedical Sciences, Hiroshima University, Kasumi 1-2-3, Minami-ku, Hiroshima 734-8553, Japan
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Di Lorenzo D, Rando G, Ciana P, Maggi A. Molecular imaging, an innovative methodology for whole-body profiling of endocrine disrupter action. Toxicol Sci 2008; 106:304-11. [PMID: 18794234 DOI: 10.1093/toxsci/kfn191] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Endocrine disrupters (EDs) are environment and food contaminants known to alter metabolic functions of mammals by interfering with specific endocrine pathways. Many EDs act on steroid hormone target cells by interacting with intracellular receptors (IRs) like estrogen receptors, androgen receptors, and thyroid hormone receptors; other receptors may be engaged. IRs are ligand-operated transcription factors acting in concert with general or cell-specific coregulators. The newly acquired awareness on the panoply of IR functions has increased the concern on potential, unsought, harmful effects of EDs on human health and has questioned the capability of currently available methodologies to identify and study EDs in the environment and in the food chain. Indeed, current in vivo and in vitro methodologies restrict the analysis to very specific organs or cell systems, with obvious limitations in predicting the systemic metabolic consequences of ED exposure. The emphasis recently laid by Regulatory Authorities, including European Center for the Validation of Alternative Methods, on the generation of in vitro model systems for toxicological analyses discouraged the development of models suitable to envision the whole spectrum of ED body actions required when studying compounds acting through IRs. Molecular imaging now provides the opportunity to quantify ED effects in living organisms enabling, for the first time, to acquire a full comprehension of the systemic effects of acute and prolonged exposure to EDs, solving the issue of the potential harm due to repeated low-dose exposure. The systems here reviewed are of unquestionable toxicological relevance and need to be taken into consideration to improve the methodology currently available and in use.
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Affiliation(s)
- Diego Di Lorenzo
- Laboratory of Biotechnology, Civic Hospital of Brescia, 25123 Brescia, Italy
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Zhang H, Wu X, Wang H, Mikheev AM, Mao Q, Unadkat JD. Effect of pregnancy on cytochrome P450 3a and P-glycoprotein expression and activity in the mouse: mechanisms, tissue specificity, and time course. Mol Pharmacol 2008; 74:714-23. [PMID: 18509067 PMCID: PMC2574889 DOI: 10.1124/mol.107.043851] [Citation(s) in RCA: 71] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The plasma concentrations of orally administered anti-human immunodeficiency virus protease inhibitors are significantly reduced during human and mouse pregnancy. We have shown that in the mouse, at gestational day 19, this reduction is due to increased hepatic cytochrome P450 3a (Cyp3a) protein expression and activity. In the current study, we investigated the mechanisms by which Cyp3a activity is increased by pregnancy and the time course of change in expression of Cyp3a and P-glycoprotein (P-gp) in various tissues. We found that hepatic transcripts of Cyp3a16, Cyp3a41, and Cyp3a44 were significantly increased during pregnancy, whereas those of Cyp3a11 and Cyp3a25 were significantly decreased. This resulted in a net increase in Cyp3a protein expression and activity in the liver during pregnancy. The increase in Cyp3a41 and Cyp3a44 transcripts was positively correlated (p < 0.05) with hepatocyte nuclear factor 6 and estrogen receptor-alpha transcripts. The pregnancy-related factors that transcriptionally activated mouse Cyp3a isoforms also activated the human CYP3A4 promoter in pregnant CYP3A4-promoter-luciferase transgenic (CYP3A4-tg) mice. In contrast, intestinal Cyp3a protein expression was not significantly affected by pregnancy. No change in P-gp protein expression was observed in the liver or kidney during pregnancy, although a significant decrease was observed in the placenta. Because hepatic CYP3A activity also seems to be induced during human pregnancy, the mouse (including CYP3A4-tg mouse) seems to be an excellent animal model to determine the molecular mechanisms for such an induction.
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Affiliation(s)
- Huixia Zhang
- Department of Pharmaceutics, University of Washington, Seattle, WA 98195, USA
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26
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Kang JH, Chung JK. Molecular-genetic imaging based on reporter gene expression. J Nucl Med 2008; 49 Suppl 2:164S-79S. [PMID: 18523072 DOI: 10.2967/jnumed.107.045955] [Citation(s) in RCA: 157] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Molecular imaging includes proteomic, metabolic, cellular biologic process, and genetic imaging. In a narrow sense, molecular imaging means genetic imaging and can be called molecular-genetic imaging. Imaging reporter genes play a leading role in molecular-genetic imaging. There are 3 major methods of molecular-genetic imaging, based on optical, MRI, and nuclear medicine modalities. For each of these modalities, various reporter genes and probes have been developed, and these have resulted in successful transitions from bench to bedside applications. Each of these imaging modalities has its unique advantages and disadvantages. Fluorescent and bioluminescent optical imaging modalities are simple, less expensive, more convenient, and more user friendly than other imaging modalities. Another advantage, especially of bioluminescence imaging, is its ability to detect low levels of gene expression. MRI has the advantage of high spatial resolution, whereas nuclear medicine methods are highly sensitive and allow data from small-animal imaging studies to be translated to clinical practice. Moreover, multimodality imaging reporter genes will allow us to choose the imaging technologies that are most appropriate for the biologic problem at hand and facilitate the clinical application of reporter gene technologies. Reporter genes can be used to visualize the levels of expression of particular exogenous and endogenous genes and several intracellular biologic phenomena, including specific signal transduction pathways, nuclear receptor activities, and protein-protein interactions. This technique provides a straightforward means of monitoring tumor mass and can visualize the in vivo distributions of target cells, such as immune cells and stem cells. Molecular imaging has gradually evolved into an important tool for drug discovery and development, and transgenic mice with an imaging reporter gene can be useful during drug and stem cell therapy development. Moreover, instrumentation improvements, the identification of novel targets and genes, and imaging probe developments suggest that molecular-genetic imaging is likely to play an increasingly important role in the diagnosis and therapy of cancer.
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Affiliation(s)
- Joo Hyun Kang
- Department of Nuclear Medicine, Cancer Research Institute, Tumor Immunity Medical Research Center, College of Medicine, Seoul National University, Seoul, Korea
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27
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Miretti S, Roato I, Taulli R, Ponzetto C, Cilli M, Olivero M, Di Renzo MF, Godio L, Albini A, Buracco P, Ferracini R. A mouse model of pulmonary metastasis from spontaneous osteosarcoma monitored in vivo by Luciferase imaging. PLoS One 2008; 3:e1828. [PMID: 18350164 PMCID: PMC2265554 DOI: 10.1371/journal.pone.0001828] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2007] [Accepted: 02/17/2008] [Indexed: 12/12/2022] Open
Abstract
Background Osteosarcoma (OSA) is lethal when metastatic after chemotherapy and/or surgical treatment. Thus animal models are necessary to study the OSA metastatic spread and to validate novel therapies able to control the systemic disease. We report the development of a syngeneic (Balb/c) murine OSA model, using a cell line derived from a spontaneous murine tumor. Methodology The tumorigenic and metastatic ability of OSA cell lines were assayed after orthotopic injection in mice distal femur. Expression profiling was carried out to characterize the parental and metastatic cell lines. Cells from metastases were propagated and engineered to express Luciferase, in order to follow metastases in vivo. Principal Findings Luciferase bioluminescence allowed to monitor the primary tumor growth and revealed the appearance of spontaneous pulmonary metastases. In vivo assays showed that metastasis is a stable property of metastatic OSA cell lines after both propagation in culture and luciferase trasduction. When compared to parental cell line, both unmodified and genetically marked metastatic cells, showed comparable and stable differential expression of the enpp4, pfn2 and prkcd genes, already associated to the metastatic phenotype in human cancer. Conclusions This OSA animal model faithfully recapitulates some of the most important features of the human malignancy, such as lung metastatization. Moreover, the non-invasive imaging allows monitoring the tumor progression in living mice. A great asset of this model is the metastatic phenotype, which is a stable property, not modifiable after genetic manipulation.
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Affiliation(s)
- Silvia Miretti
- Department of Morphophysiology, School of Veterinary Medicine, University of Torino, Grugliasco, Turin, Italy.
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Mice as clinically relevant models for the study of cytochrome P450-dependent metabolism. Clin Pharmacol Ther 2008; 83:818-28. [PMID: 18388875 DOI: 10.1038/clpt.2008.50] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The cytochrome P450 (CYP) gene superfamily comprises a large group of hemoproteins with diverse functions in steroid, lipid, and xenobiotic metabolism. The human genome is estimated to contain 57 genes that encode functional CYP proteins, a number of which are important for the metabolism of foreign chemicals, including carcinogens and most therapeutic drugs. Given that metabolic interactions are a major source of adverse drug interactions, a comprehensive understanding of CYP function is critically important for the development and safe clinical application of drugs. While some cross-species genetic conservation of CYPs exists, drug metabolism can differ between humans and other mammalian species. The development of humanized mice that replicate many aspects of human drug metabolism has provided invaluable experimental models that circumvent this limitation to a considerable degree. This brief review focuses on the value and limitations of mouse models for the study of drug metabolism in humans.
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Zhang Y, Bressler JP, Neal J, Lal B, Bhang HEC, Laterra J, Pomper MG. ABCG2/BCRP expression modulates D-Luciferin based bioluminescence imaging. Cancer Res 2007; 67:9389-97. [PMID: 17909048 DOI: 10.1158/0008-5472.can-07-0944] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Bioluminescence imaging (BLI) is becoming indispensable to the study of transgene expression during development and, in many in vivo models of disease such as cancer, for high throughput drug screening in vitro. Because reaction of d-luciferin with firefly luciferase (fLuc) produces photons of sufficiently long wavelength to permit imaging in intact animals, use of this substrate and enzyme pair has become the method of choice for performing BLI in vivo. We now show that expression of the ATP-binding cassette (ABC) family transporter ABCG2/BCRP affects BLI signal output from the substrate d-luciferin. In vitro studies show that d-luciferin is a substrate for ABCG2/BCRP but not for the MDR1 P-glycoprotein (ABCB1/Pgp), multidrug resistance protein 1 (MRP1/ABCC1), or multidrug resistance protein 2 (MRP2/ABCC2). d-Luciferin uptake within cells is shown to be modulated by ABC transporter inhibitors, including the potent and selective ABCG2/BCRP inhibitor fumitremorgin C. Images of xenografts engineered to express transgenic ABCG2/BCRP, as well as xenografts derived from the human prostate cancer cell line 22Rv1 that naturally express ABCG2/BCRP, show that ABCG2/BCRP expression and function within regions of interest substantially influence d-luciferin-dependent bioluminescent output in vivo. These findings highlight the need to consider ABCG2/BCRP effects during d-luciferin-based BLI and suggest novel high throughput methods for identifying new ABCG2/BCRP inhibitors.
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Affiliation(s)
- Yimao Zhang
- Russell H. Morgan Department of Radiology, The Johns Hopkins Bloomberg School of Public Health, The Johns Hopkins School of Medicine, Baltimore, Maryland, USA
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Ottobrini L, Ciana P, Moresco R, Lecchi M, Belloli S, Martelli C, Todde S, Fazio F, Gambhir SS, Maggi A, Lucignani G. Development of a bicistronic vector for multimodality imaging of estrogen receptor activity in a breast cancer model: preliminary application. Eur J Nucl Med Mol Imaging 2007; 35:365-78. [PMID: 17926035 DOI: 10.1007/s00259-007-0578-z] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2007] [Accepted: 08/28/2007] [Indexed: 11/30/2022]
Abstract
PURPOSE The aim of this study was to develop a cellular model for the concurrent imaging of reporter genes expression by using positron emission tomography (PET) and bioluminescence imaging (BLI) for the assessment of estrogen receptor activity in vivo in a breast cancer model. METHODS Two reporters were chosen: a mutated form of the dopaminergic D2 receptor (D(2)R80A) for PET imaging, and the Firefly Luciferase for BLI. The presence of an IRES sequence between the two reporters ensured the coordinated expression driven by the same regulatory sequence containing an estrogen responsive element (ERE). To prevent chromatin effects on reporter expression, the construct was flanked by insulator sequences (Matrix Attachment Region, MAR). RESULTS In vitro studies showed that the vector was efficient in coordinating the expression of the two genes. Moreover, stably transfected cells implanted in recipient animals maintained their capacity to express the reporters and react to systemic treatments permitting the in vivo study of ERs activity by PET and BLI imaging. In vitro expression analysis after long-term treatments showed different behaviour of the two reporter proteins in monitoring estrogen-dependent transcription outlining the importance of multi-reporter systems. With this model, PET and BLI can be applied to the concurrent evaluation of gene expression induced by estrogen and its analogues by using a bicistronic construct. CONCLUSION The combined features of rapid, sensitive, sequential BLI and tomographic and quantitative PET imaging will allow the use of this strategy for the in vivo evaluation of molecular processes also for pharmacodynamic studies.
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Affiliation(s)
- Luisa Ottobrini
- Institute of Radiological Sciences, University of Milan, Unit of Nuclear Medicine, Hospital San Paolo, Milan, Italy
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Abstract
The use of molecular imaging techniques in the central nervous system (CNS) has a rich history. Most of the important developments in imaging-such as computed tomography, magnetic resonance imaging, single photon emission computed tomography, and positron emission tomography-began with neuropsychiatric applications. These techniques and modalities were then found to be useful for imaging other organs involved with various disease processes. Molecular imaging of the CNS has enabled scientists and researchers to understand better the basic biology of brain function and the way in which various disease processes affect the brain. Unlike other organs, the brain is not easily accessible, and it has a highly selective barrier at the endothelial cell level known as the blood-brain barrier. Furthermore, the brain is the most complex cellular network known to exist. Various neurotransmitters act in either an excitatory or an inhibitory fashion on adjacent neurons through a multitude of mechanisms. The various neuronal systems and the myriad of neurotransmitter systems become altered in many diseases. Some of the most devastating diseases, including Alzheimer disease, Parkinson disease, brain tumors, psychiatric disease, and numerous degenerative neurologic diseases, affect only the brain. Molecular neuroimaging will be critical to the future understanding and treatment of these diseases. Molecular neuroimaging of the brain shows tremendous promise for clinical application. In this article, the current state and clinical applications of molecular neuroimaging will be reviewed.
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Affiliation(s)
- Dima A Hammoud
- Department of Radiology, Johns Hopkins University School of Medicine, 1550 Orleans St, CRB-2, Room 492, Baltimore, MD 21231, USA
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Biggs JS, Wan J, Cutler NS, Hakkola J, Uusimäki P, Raunio H, Yost GS. Transcription factor binding to a putative double E-box motif represses CYP3A4 expression in human lung cells. Mol Pharmacol 2007; 72:514-25. [PMID: 17548528 DOI: 10.1124/mol.106.033795] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Two vital enzymes of the CYP3A subfamily, CYP3A4 and CYP3A5, are differentially expressed in the human lung. However, the molecular mechanisms that regulate tissue-selective expression of the genes are poorly understood. The ability of the 5' upstream promoter region of these two genes to drive luciferase reporter activities in human lung A549 cells was dramatically different. The CYP3A5 promoter region activated luciferase gene expression by 10-fold over the promoterless construct, whereas the CYP3A4 promoter did not drive expression. Sequence comparisons of the promoters identified a 57-base pair insertion in the CYP3A4 promoter region (-71 to -127) that was absent in the CYP3A5 promoter. Deletion of the 57-bp motif from CYP3A4 or insertion into the CYP3A5 promoter, showed that this motif represses CYP3A4 expression in lung. EMSA analysis using nuclear extracts from either A549 cells or human lung tissues showed two specific protein/DNA complexes formed with the (32)P-labeled CYP3A4 57-bp oligonucleotide. EMSA analyses identified two E-box motifs as the minimal specific cis-elements. Supershift assays with antibodies directed against known double- or single-E-box binding factors (TAL1, deltaEF1, E2A, HEB, etc.) failed to identify this factor as a previously characterized trans-acting double E-box binding protein. These results demonstrated that the 5'-upstream region of CYP3A4 contains an active putative double E-box repressor motif, not present in the 5'-upstream region of the CYP3A5 gene, that attenuates CYP3A4 expression in the human lung. We believe that this is the first documented case in which a cytochrome P450 gene is actively repressed in a tissue-specific manner.
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Affiliation(s)
- Jason S Biggs
- Department of Pharmacology and Toxicology, University of Utah, Salt Lake City, UT 84112-5820, USA
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Abstract
Much effort to extrapolate the in vivo pharmacokinetics of drugs in human from experimental animals or in vitro studies has been made by many researchers. A urokinase-type plasminogen activator+/+/severe combined immunodeficient transgenic mouse line, in which the liver could be replaced by more than 80% with human hepatocytes, was established recently in Japan. This chimeric mouse line is remarkable because the replacement is higher than any other chimeric mouse reported previously. Since the liver is the critical organ involved in the pharmacokinetics of drugs, human liver is essential for the development of new drugs. To predict the human drug metabolism and pharmacokinetics, human hepatocytes and liver microsomes are recognized as better tools and are frequently used. Thus, chimeric mice with humanized liver would have great advantages in studies on drug metabolism and pharmacokinetics. We have evaluated chimeric mice for studies on absorption, distribution, metabolism, and excretion (ADME). In the liver of the chimeric mice, human phase I and phase II enzymes were clarified to be expressed and to have a similar drug metabolizing capacity as the donor. Human specific metabolites could be detected in the serum, suggesting that the chimeric mice might be used as a human ADME model for both in vitro and in vivo studies. For predicting human drug interactions, enzyme induction and inhibition are serious problems. By the treatment with typical inducers, human CYP1A2 and CYP3A4 expressed in the liver of the chimeric mice had induction potencies. After the treatment with quinidine, a specific inhibitor of human CYP2D6, the area under the curve (AUC) of a CYP2D6 metabolite, 4'-hydroxydebrisoquin, was significantly decreased in the chimeric mice but not in the control mice. Therefore, it was indicated that the chimeric mice could be used for assessing the drug interactions via enzyme induction and inhibition. As well as drug metabolism, the drug excretion was demonstrated to be humanized because cefmetazole was mainly excreted in urine both in the chimeric mice and human but in feces in control uPA-/-/SCID mice. In this review, basic researches on ADME in the chimeric mice with humanized liver are summarized and the application of the chimeric mice for predictive ADME is proposed.
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Affiliation(s)
- Miki Katoh
- Division of Pharmaceutical Sciences, Graduate School of Medical Science, Kanazawa University, Japan
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34
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Houten SM, Volle DH, Cummins CL, Mangelsdorf DJ, Auwerx J. In Vivo Imaging of Farnesoid X Receptor Activity Reveals the Ileum as the Primary Bile Acid Signaling Tissue. Mol Endocrinol 2007; 21:1312-23. [PMID: 17426284 DOI: 10.1210/me.2007-0113] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
We generated and characterized a firefly luciferase reporter mouse for the nuclear receptor farnesoid X receptor (FXR). This FXR reporter mouse has basal luciferase expression in the terminal ileum, an organ with well-characterized FXRalpha signaling. In vivo luciferase activity reflected the diurnal activity pattern of the mouse, and is regulated by both natural (bile acids, chenodeoxycholic acid) and synthetic (GW4064) FXRalpha ligands. Moreover, in vivo and in vitro analysis showed luciferase activity after GW4064 administration in the liver, kidney, and adrenal gland, indicating that FXRalpha signaling is functional in these tissues. Hepatic luciferase activity was robustly induced in cholestatic mice, showing that FXRalpha signaling pathways are activated in this disease. In conclusion, we have developed an FXR reporter mouse that is useful to monitor FXRalpha signaling in vivo in health and disease. The use of this animal could facilitate the development of new therapeutic compounds that target FXRalpha in a tissue-specific manner.
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Affiliation(s)
- Sander M Houten
- Institut de Génétique et Biologie Moléculaire et Cellulaire, Centre National de la Recherche Scientifique/Institut National de la Santé et de la Recherche Médicale/Université Louis Pasteur, Illkirch, France
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35
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Bednar B, Zhang GJ, Williams Jr DL, Hargreaves R, Sur C. Optical molecular imaging in drug discovery and clinical development. Expert Opin Drug Discov 2007; 2:65-85. [DOI: 10.1517/17460441.2.1.65] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
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36
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Gardner-Stephen DA, Mackenzie PI. Hepatocyte nuclear factor1 transcription factors are essential for the UDP-glucuronosyltransferase 1A9 promoter response to hepatocyte nuclear factor 4α. Pharmacogenet Genomics 2007; 17:25-36. [PMID: 17264800 DOI: 10.1097/fpc.0b013e32801112b5] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
In humans, UDP-glucuronosyltransferase 1A9 is known to glucuronidate numerous lipophilic substances of pharmacological and toxicological importance. Although it has been established that individuals vary in their capacity to express this detoxification enzyme, little is known about the mechanisms that dictate the regulation of UGT1A9. In particular, it is not understood why, while the proximal regulatory regions of the UGT1A7-10 gene cluster are highly similar, UGT1A9 is the sole hepatic isoform of the four. Recent data have suggested that the human UGT1A9 promoter is controlled by hepatocyte nuclear factor 4alpha. In this work, we confirm that the human UGT1A9 promoter can indeed be upregulated by human hepatocyte nuclear factor 4alpha in vitro. Our results, however, show that the previously-reported hepatocyte nuclear factor 4alpha-binding site only plays a minor role in this response. Instead, upregulation was found to require a more proximal response element, which was not preserved in the UGT1A7, UGT1A8 or UGT1A10 promoters. Furthermore, hepatocyte nuclear factor 4alpha-mediated transcription from the human UGT1A9 promoter was discovered to be entirely dependent on hepatocyte nuclear factor 1. We have established that two hepatocyte nuclear factor 1-binding elements are involved in this phenomenon, the more distal of which is unique to the UGT1A9 promoter. Interestingly, this second site had no significant role in hepatocyte nuclear factor 1alpha-mediated induction of the UGT1A9 promoter in vitro, yet was critical for upregulation by human hepatocyte nuclear factor 4alpha. The discovery of two unique and cooperative liver-enriched transcription factor binding sites in the UGT1A9 promoter is a significant step towards understanding the unique hepatic expression of UGT1A9 amongst the UGT1A7-10 gene cluster.
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Affiliation(s)
- Dione A Gardner-Stephen
- Department of Clinical Pharmacology, Flinders University School of Medicine, Flinders Medical Centre, South Australia, Australia
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37
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Lowik CWGM, Cecchini MG, Maggi A, van der Pluijm G. Noninvasive Real-Time In Vivo Bloluminescent Imaging of Gene Expression and of Tumor Progression and Metastasis. Mol Imaging 2006:193-227. [PMID: 15524218 DOI: 10.1007/3-540-26809-x_11] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Affiliation(s)
- C W G M Lowik
- Department of Endocrinology, Leiden University Medical Center, The Netherlands.
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38
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Gross S, Piwnica-Worms D. Molecular imaging strategies for drug discovery and development. Curr Opin Chem Biol 2006; 10:334-42. [PMID: 16822702 DOI: 10.1016/j.cbpa.2006.06.028] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2006] [Accepted: 06/22/2006] [Indexed: 11/27/2022]
Abstract
Recent advances in non-invasive molecular imaging provide exciting opportunities for discovery, validation and development of novel therapeutics. As the arsenal of detection devices and strategies, injectable probes, genetically encoded reporters and animal models rapidly expands, molecular imaging is becoming indispensable for drug discovery and development. Not only do such strategies reduce the time, cost and workload associated with conventional destructive end-point assays, but they also enable spatial and temporal monitoring of in vivo gene expression, signaling pathways, biochemical reactions and targets as they relate to the pharmacokinetics and pharmacodynamics of novel drugs.
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Affiliation(s)
- Shimon Gross
- Molecular Imaging Center, Mallinckrodt Institute of Radiology, and Department of Molecular Biology and Pharmacology, Washington University Medical School, Saint Louis, MO 63110, USA
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39
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Abstract
Most xenobiotics that enter the body are subjected to metabolism that functions primarily to facilitate their elimination. Metabolism of certain xenobiotics can also result in the production of electrophilic derivatives that can cause cell toxicity and transformation. Many xenobiotics can also activate receptors that in turn induce the expression of genes encoding xenobiotic-metabolizing enzymes and xenobiotic transporters. However, there are marked species differences in the way mammals respond to xenobiotics, which are due in large part to molecular differences in receptors and xenobiotic-metabolizing enzymes. This presents a problem in extrapolating data obtained with rodent model systems to humans. There are also polymorphisms in xenobiotic-metabolizing enzymes that can impact drug therapy and cancer susceptibility. In an effort to generate more reliable in vivo systems to study and predict human response to xenobiotics, humanized mice are under development.
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Affiliation(s)
- Frank J Gonzalez
- Laboratory of Metabolism, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA.
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40
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Lemaire G, Mnif W, Pascussi JM, Pillon A, Rabenoelina F, Fenet H, Gomez E, Casellas C, Nicolas JC, Cavaillès V, Duchesne MJ, Balaguer P. Identification of New Human Pregnane X Receptor Ligands among Pesticides Using a Stable Reporter Cell System. Toxicol Sci 2006; 91:501-9. [PMID: 16565514 DOI: 10.1093/toxsci/kfj173] [Citation(s) in RCA: 131] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Pregnane X receptor (PXR, NR1I2) is activated by various chemically unrelated compounds, including environmental pollutants and drugs. We proceeded here to in vitro screening of 28 pesticides with a new reporter system that detects human pregnane X receptor (hPXR) activators. The cell line was obtained by a two-step stable transfection of cervical cancer HeLa cells. The first transfected cell line, HG5LN, contained an integrated luciferase reporter gene under the control of a GAL4 yeast transcription factor-binding site. The second cell line HGPXR was derived from HG5LN and stably expressed hPXR ligand-binding domain fused to GAL4 DNA-binding domain (DBD). The HG5LN cells were used as a control to detect nonspecific activities. Pesticides from various chemical classes were demonstrated, for the first time, to be hPXR activators: (1) herbicides: pretilachlor, metolachlor, and alachlor chloracetanilides, oxadiazon oxiconazole, and isoproturon urea; (2) fungicides: bupirimate and fenarimol pyrimidines, propiconazole, fenbuconazole, prochloraz conazoles, and imazalil triazole; and (3) insecticides: toxaphene organochlorine, permethrin pyrethroid, fipronil pyrazole, and diflubenzuron urea. Pretilachlor, metolachlor, bupirimate, and oxadiazon had an affinity for hPXR equal to or greater than the positive control rifampicin. Some of the newly identified hPXR activators were also checked for their ability to induce cytochrome P450 3A4 expression in a primary culture of human hepatocytes. HGPXR, with HG5LN as a reference, was grafted onto nude mice to assess compound bioavailability through in vivo quantification of hPXR activation. Altogether, our data indicate that HGPXR cells are an efficient tool for identifying hPXR ligands and establishing pesticides as hPXR activators.
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Ottobrini L, Ciana P, Biserni A, Lucignani G, Maggi A. Molecular imaging: a new way to study molecular processes in vivo. Mol Cell Endocrinol 2006; 246:69-75. [PMID: 16388894 DOI: 10.1016/j.mce.2005.11.013] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Non-invasive imaging of reporter gene expression using different imaging modalities is increasing its role for the in vivo assessment of molecular processes. Multimodality imaging protocols overcome limitations to a single imaging modality and provide a thorough view of specific processes, often allowing a quantitative measurement and direct visualization of the process in a specific target organ or tissue. The use of the right reporter gene for the development of animal models and the characterization of its expression in different conditions and tissues is fundamental for basic, translational and future pharmacological applications of a given model. This paper summarizes the major steps in the development and evaluation of a specific animal model for in vivo molecular imaging studies and describes the first example of an animal model designed for the in vivo assessment of a specific receptor activity and its possible evolution towards multimodality imaging analysis.
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Affiliation(s)
- L Ottobrini
- Center of Excellence on Neurodegenerative Diseases, Department of Pharmacological Sciences, University of Milan, Via Balzaretti 9, 20133 Milan, Italy
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42
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Siman-Tov T, Meiner V, Gadoth N. Could steroids mask the diagnosis of cerebrotendinous xanthomatosis? J Neurol Sci 2006; 243:83-6. [PMID: 16445943 DOI: 10.1016/j.jns.2005.10.019] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2005] [Revised: 10/18/2005] [Accepted: 10/18/2005] [Indexed: 10/25/2022]
Abstract
Cerebrotendinous xanthomatosis (CTX) is a rare autosomal recessive disorder of bile acid synthesis, caused by impaired hydroxylation of cholesterol side chains due to deficiency of the mitochondrial enzyme sterol 27-hydroxylase (CYP27A1), leading to accumulation of cholestanol and cholesterol in brain and other tissues. Elevated plasma cholestanol serves as a key marker for the clinical diagnosis of CTX. In the present report we describe a young man with CTX who was on high dose steroids for a misdiagnosed chronic inflammatory demyelinating polyneuropathy (CIDP) and had normal level of serum cholestanol. When steroids were discontinued, markedly elevated serum cholestanol was measured concomitant with marked clinical worsening. This observation may imply that steroids can lower plasma cholestanol, possibly by directly inducing residual CYP27A1 activity or by inducing alternative pathways for cholestanol elimination.
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Affiliation(s)
- Tali Siman-Tov
- Department of Neurology, Meir General Hospital Kfar-Saba, and the Sackler Faculty of Medicine, Tel-Aviv University, Israel
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43
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Nishimura M, Yoshitsugu H, Yokoi T, Tateno C, Kataoka M, Horie T, Yoshizato K, Naito S. Evaluation of mRNA expression of human drug-metabolizing enzymes and transporters in chimeric mouse with humanized liver. Xenobiotica 2006; 35:877-90. [PMID: 16308282 DOI: 10.1080/00498250500307251] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
The hepatic mRNA expression of human drug-metabolizing enzymes and transporters in chimeric mise with almost-completely humanized liver (replacement index: 71-89%) was investigated. The mRNAs of 58 human phase I enzymes, 26 human phase II enzymes, 23 human transporters, and five mouse Cyps were measured in the chimeric mice with humanized liver generated using hepatocytes from a Japanese donor. The mRNA expression of 52 human phase I enzymes, which includes 20 human CYPs, 26 human phase II enzymes and 21 human transporters was ascertained in the chimeric mouse liver. Among them, the expression of the target mRNAs vital for liver function such as the metabolism and secretion of endogenous compounds appeared to be maintained. The central value for the expression ratio in all target genes in chimeric mouse liver to the donor liver was 0.46, which was lower than the substitution rate of chimeric mouse liver by donor liver. The ratio of mouse Cyp mRNA expression of chimeric mouse liver to that of control mouse liver was 0.19 or less, except for that of Cyp2b10. There were good correlations between the mRNA expression levels of human hepatic albumin gene, the values of the rate of replacement of mouse liver by human liver, and the human blood albumin concentration in the chimeric mice. The chimeric mice with humanized liver may be a useful tool for the evaluation of drug-drug interactions such as the inhibition and induction of drug-metabolizing enzymes and transporters.
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Affiliation(s)
- M Nishimura
- Division of Pharmacology, Drug Safety and Metabolism, Otsuka Pharmaceutical Factory, Inc., Naruto, Tokushima, Japan
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44
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Abstract
Luciferase enzymes catalyze the emission of light from a substrate -- a phenomenon known as bioluminescence -- and have been employed as reporters of many biological functions. Luminescent reporters are much dimmer than fluorescent reporters, and therefore provide relatively modest spatial and temporal resolution. Yet, they are generally more sensitive and less toxic, making them particularly useful for long-term longitudinal studies of living cells, tissues and whole animals. Bioluminescence imaging has proven useful for detecting protein-protein interactions, for tracking cells in vivo, and for monitoring the transcriptional and post-transcriptional regulation of specific genes. Recent applications have included longitudinal monitoring of tumor progression in vivo, and monitoring circadian rhythms with single-cell resolution.
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Affiliation(s)
- David K Welsh
- Department of Cell Biology, The Scripps Research Institute, La Jolla, CA 92037, USA
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45
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Katoh M, Matsui T, Nakajima M, Tateno C, Soeno Y, Horie T, Iwasaki K, Yoshizato K, Yokoi T. In vivo induction of human cytochrome P450 enzymes expressed in chimeric mice with humanized liver. Drug Metab Dispos 2005; 33:754-63. [PMID: 15769886 DOI: 10.1124/dmd.104.002600] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
The induction and inhibition of human cytochrome P450 (P450) enzymes are clinically responsible for drug interactions. Although the induction of P450s is investigated using human hepatocytes in the drug development process, there are some disadvantages, such as the decline of the enzyme activity during culture. In the present study, we examined the in vivo induction potency in chimeric mice with humanized liver, which was recently established in Japan to clarify whether this chimeric mouse model would be more suitable for human induction studies. Rifampicin and 3-methylcholanthrene (3-MC) were used in vivo as typical P450 inducers in the chimeric mice. The expression levels of human CYP3A4 mRNA and CYP3A4 protein and dexamethasone 6-hydroxylase activity, specific for human CYP3A4, were increased 8- to 22-, 3- to 10-, and 5- to 12-fold, respectively, by treatment with rifampicin. In addition, the expression levels of human CYP1A2 mRNA and CYP1A2 protein were also increased 2- to 9- and 5-fold, respectively, by treatment with 3-MC. Although other human P450s are expressed in the chimeric mice, there were few effects by the treatment of rifampicin and 3-MC on the mRNA, protein, and enzyme activity of those P450s. It was demonstrated that human P450s expressed in the chimeric mice with humanized liver were induced by rifampicin and 3-MC. This chimeric mouse model may be a useful animal model to estimate and predict the in vivo induction of P450s in humans.
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Affiliation(s)
- Miki Katoh
- Division of Pharmaceutical Sciences, Graduate School of Medical Science, Kanazawa University, Kanazawa 920-1192, Japan
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46
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Abstract
Genetically encoded imaging reporters introduced into cells and transgenic animals enable noninvasive, longitudinal studies of dynamic biological processes in vivo. The most common reporters include firefly luciferase (bioluminescence imaging), green fluorescence protein (fluorescence imaging), herpes simplex virus-1 thymidine kinase (positron emission tomography), and variants with enhanced spectral and kinetic properties. When cloned into promoter/enhancer sequences or engineered into fusion proteins, imaging reporters allow transcriptional regulation, signal transduction, protein-protein interactions, oncogenic transformation, cell trafficking, and targeted drug action to be spatiotemporally resolved in vivo. Spying on cancer with genetically encoded imaging reporters provides insight into cancer-specific molecular machinery within the context of the whole animal.
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Affiliation(s)
- Shimon Gross
- Molecular Imaging Center, Mallinckrodt Institute of Radiology, Department of Molecular Biology and Pharmacology, Washington University Medical School, St. Louis, Missouri 63110, USA
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47
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Heine HL, Leong HS, Rossi FMV, McManus BM, Podor TJ. Strategies of Conditional Gene Expression in Myocardium. MOLECULAR CARDIOLOGY 2005; 112:109-54. [PMID: 16010014 DOI: 10.1007/978-1-59259-879-3_8] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
The use of specialized reporter genes to monitor real-time, tissue-specific transgene expression in animal models offers an opportunity to circumvent current limitations associated with the establishment of transgenic mouse models. The Cre-loxP and the tetracycline (Tet)-inducible systems are useful methods of conditional gene expression that allow spatial (cell-type-specific) and temporal (inducer-dependent) control. Most often, the alpha-myosin heavy chain (alpha-MHC) promoter is used in these inducible systems to restrict expression of reporter genes and transgenes to the myocardium. An overview of each inducible system is described, along with suggested reporter genes for real-time, noninvasive imaging in the myocardium. Effective gene delivery of the inducible gene expression system is carried out by lentiviral vectors, which offer high transduction efficiency, long-term transgene expression, and low immunogenicity. This chapter outlines the packaging of myocardium-specific inducible expression systems into lentiviral vectors, in which a transgene and a reporter gene are transduced into cardiomyocytes. In doing so, transgene and reporter expression can be monitored/tracked with bioluminescence imaging (BLI) and positron emission tomography (PET).
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Affiliation(s)
- Heather L Heine
- The James Hogg iCAPTURE Center for Cardiovascular and Pulmonary Research/MRL, University of British Columbia, St. Paul's Hospital, Vancouver, Canada
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48
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Katoh M, Matsui T, Nakajima M, Tateno C, Kataoka M, Soeno Y, Horie T, Iwasaki K, Yoshizato K, Yokoi T. Expression of human cytochromes P450 in chimeric mice with humanized liver. Drug Metab Dispos 2004; 32:1402-10. [PMID: 15383493 DOI: 10.1124/dmd.104.001347] [Citation(s) in RCA: 97] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Recently, a chimeric mouse line in which the liver could be replaced by more than 80% with human hepatocytes was established in Japan. Because the chimeric mouse produces human albumin (hAlb), replacement by human hepatocytes could be estimated by the hAlb concentration in the blood of chimeric mice. In this study, we investigated human major cytochrome P450 (P450) in the livers of chimeric mice by mRNA, protein, and enzyme activity using real-time polymerase chain reaction, Western blot analysis, and high-performance liquid chromatography, respectively. Chimeric mice with humanized liver generated using hepatocytes from a Japanese and white donor were used. Human P450 mRNAs were expressed in the liver of chimeric mice, and major human P450 proteins such as CYP1A2, CYP2C9, and CYP3A4 were detected. The expression of P450 mRNA and protein was correlated with the hAlb concentration in the blood. The enzyme activities such as diclofenac 4'-hydroxylase activity, dexamethasone 6-hydroxylase activity, and coumarin 7-hydroxylase activity, activities that are specific to human P450 but not to murine P450, were increased in a hAlb concentration-dependent manner. The chimeric mice with nearly 90% replacement by human hepatocytes demonstrated almost the same protein contents of human P450s and drug-metabolizing enzyme activity as those of the donor. It was confirmed that genomic DNA from the livers of the chimeric mice and that from the liver of the donor exhibited the same genotype. In conclusion, the chimeric mice exhibited a similarly efficient capacity of drug metabolism as humans, suggesting that they could be a useful animal model for drug development.
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Affiliation(s)
- Miki Katoh
- Division of Pharmaceutical Sciences, Graduate School of Medical Science, Kanazawa University, Kakuma-machi, Kanazawa 920-1192, Japan
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49
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Maggi A, Ottobrini L, Biserni A, Lucignani G, Ciana P. Techniques: Reporter mice – a new way to look at drug action. Trends Pharmacol Sci 2004; 25:337-42. [PMID: 15165750 DOI: 10.1016/j.tips.2004.04.007] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
During the past decade remarkable progress in molecular genetics and the possibility of manipulating cells so that the expression of genes can directly 'report' on drug activity has produced major changes in drug development strategies. The recent description and pharmacological validation of reporter mice for in vivo analysis of hormone receptor activity opens new horizons for drug discovery. These novel animal models, in association with in vivo imaging technologies, provide a global view of the target tissues of drug action following acute and repeated drug treatment, thus enabling the prediction of potential side-effects in the early phase of preclinical studies. It is anticipated that further improvements of transgene architecture will lead to models that combine pharmacokinetic, pharmacodynamic and toxicological studies in a single step, which should provide a tremendous saving in time and, paradoxically, the number of animals to be sacrificed in the development of novel pharmacologically active molecules.
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Affiliation(s)
- Adriana Maggi
- Center of Excellence on Neurodegenerative Diseases and Department of Pharmacological Sciences, University of Milan, Via Balzaretti 9, 20133 Milan, Italy.
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50
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Zhang W, Purchio AF, Coffee R, West DB. Differential regulation of the human CYP3A4 promoter in transgenic mice and rats. Drug Metab Dispos 2004; 32:163-7. [PMID: 14744936 DOI: 10.1124/dmd.32.2.163] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Previously we described a transgenic mouse model [FVB/NTg(CYP3A4-luc)Xen] using a reporter construct consisting of 13 kilobases of the human CYP3A4 promoter driving the firefly luciferase gene in the inbred FVB/N mouse strain. Here we report regulation of the same CYP3A4-luc reporter gene in a transgenic outbred mouse strain (CD-1) and in a transgenic rat (Sprague-Dawley). Basal reporter expression and responses to several xenobiotics in the transgenic CD-1 mice [CD-1/Crl-Tg(CYP3A4-luc)Xen] were similar to those in the transgenic FVB/N mice. In both mouse backgrounds, the basal levels of the reporter were higher in male compared with female, and in the FVB/N strain there was greater induction for all drugs in male compared with female; however, in the CD-1 background this gender difference for induction was not obvious. In contrast with transgenic mice, transgenic rats [SD/Tac-Tg(CYP3A4-luc)Xen] expressed the luciferase reporter at higher basal levels in female compared with male rats. Responses to some compounds were much greater in rats than in mice, and the kinetics of induction was different with peak induction occurring later in the rat compared with the mouse. Our results suggest that the human CYP3A4 promoter is regulated differently in transgenic mice and rats in some aspects.
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Affiliation(s)
- Weisheng Zhang
- Xenogen Corporation, 860 Atlantic Avenue, Alameda, CA 94501, USA.
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