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Zhang M, Rottschäfer V, C M de Lange E. The potential impact of CYP and UGT drug-metabolizing enzymes on brain target site drug exposure. Drug Metab Rev 2024; 56:1-30. [PMID: 38126313 DOI: 10.1080/03602532.2023.2297154] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2023] [Accepted: 12/15/2023] [Indexed: 12/23/2023]
Abstract
Drug metabolism is one of the critical determinants of drug disposition throughout the body. While traditionally associated with the liver, recent research has unveiled the presence and functional significance of drug-metabolizing enzymes (DMEs) within the brain. Specifically, cytochrome P-450 enzymes (CYPs) and UDP-glucuronosyltransferases (UGTs) enzymes have emerged as key players in drug biotransformation within the central nervous system (CNS). This comprehensive review explores the cellular and subcellular distribution of CYPs and UGTs within the CNS, emphasizing regional expression and contrasting profiles between the liver and brain, humans and rats. Moreover, we discuss the impact of species and sex differences on CYPs and UGTs within the CNS. This review also provides an overview of methodologies for identifying and quantifying enzyme activities in the brain. Additionally, we present factors influencing CYPs and UGTs activities in the brain, including genetic polymorphisms, physiological variables, pathophysiological conditions, and environmental factors. Examples of CYP- and UGT-mediated drug metabolism within the brain are presented at the end, illustrating the pivotal role of these enzymes in drug therapy and potential toxicity. In conclusion, this review enhances our understanding of drug metabolism's significance in the brain, with a specific focus on CYPs and UGTs. Insights into the expression, activity, and influential factors of these enzymes within the CNS have crucial implications for drug development, the design of safe drug treatment strategies, and the comprehension of drug actions within the CNS. To that end, CNS pharmacokinetic (PK) models can be improved to further advance drug development and personalized therapy.
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Affiliation(s)
- Mengxu Zhang
- Division of Systems Pharmacology and Pharmacy, Predictive Pharmacology Group, Leiden Academic Centre of Drug Research, Leiden University, Leiden, The Netherlands
| | - Vivi Rottschäfer
- Mathematical Institute, Leiden University, Leiden, The Netherlands
- Korteweg-de Vries Institute for Mathematics, University of Amsterdam, Amsterdam, The Netherlands
| | - Elizabeth C M de Lange
- Division of Systems Pharmacology and Pharmacy, Predictive Pharmacology Group, Leiden Academic Centre of Drug Research, Leiden University, Leiden, The Netherlands
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2
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Allam AM, AbuBakr HO, Yassin AM, Abdel-Razek AS, Khattab MS, Gouda EM, Mousa SZ. Potential chemopreventive effects of Broccoli extract supplementation against 7, 12 dimethyl Benz(a)anthracene (DMBA) -induced toxicity in female rats. Sci Rep 2023; 13:17234. [PMID: 37821474 PMCID: PMC10567736 DOI: 10.1038/s41598-023-43629-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2023] [Accepted: 09/26/2023] [Indexed: 10/13/2023] Open
Abstract
Dietary components have recently received rapidly expanding attention for their potential to halt or reverse the development of many oxidative stress-mediated diseases after exposure to environmental toxicants. 7, 12 dimethylbenz(a)anthracene (DMBA) is one of the most common environmental pollutants. The present study aimed to evaluate the chemo-preventive effects of broccoli as a nutritional component against DMBA intoxication in rats. A daily dose of aqueous (1 ml/rat) and methanolic (150 mg/kg) broccoli extracts, respectively, was given to 50-day-old female rats for 26 successive weeks after carcinogen intoxication with a single dose of 20 mg/ml of DMBA. DMBA intoxication resulted in a redox imbalance (a decreased GSH level and an increased MDA level) and increased DNA fragmentation in the liver, kidney, and brain. Besides, it affected the level of expression of the bcl2 gene in the liver, kidney, and brain tissue but didn't affect cfos gene expression accompanied by histopathological changes. The aqueous and methanolic broccoli extract supplements ameliorated the adverse effects by increasing the level of GSH, decreasing the MDA level, and reducing DNA fragmentation. Besides, broccoli extracts decreased the expression of bcl2 in the liver and brain and up-regulated bcl2 expression in the kidney, accompanied by lowering NF-κβ 65 expression in the liver and brain and γ-catenin expression in the liver and kidney. In conclusion, broccoli as a dietary component had a strong chemoprotective effect against oxidative stress, DNA damage, and genotoxicity induced by DMBA intoxication in rats.
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Affiliation(s)
- Aya M Allam
- Department of Biochemistry and Molecular Biology, Faculty of Veterinary Medicine, Cairo University, Giza, 12211, Egypt
| | - Huda O AbuBakr
- Department of Biochemistry and Molecular Biology, Faculty of Veterinary Medicine, Cairo University, Giza, 12211, Egypt.
| | - Aya M Yassin
- Department of Biochemistry and Molecular Biology, Faculty of Veterinary Medicine, Cairo University, Giza, 12211, Egypt
| | - Ahmed S Abdel-Razek
- Department of Microbial Chemistry, Genetic Engineering and Biotechnology Research Division, National Research Centre, Dokki- Giza, Egypt
| | - Marwa S Khattab
- Department of Pathology, Faculty of Veterinary Medicine, Cairo University, Giza, Egypt
| | - Eman M Gouda
- Department of Biochemistry and Molecular Biology, Faculty of Veterinary Medicine, Cairo University, Giza, 12211, Egypt
| | - Said Z Mousa
- Department of Biochemistry and Molecular Biology, Faculty of Veterinary Medicine, Cairo University, Giza, 12211, Egypt
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3
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Stocco MR, Tyndale RF. Cytochrome P450 enzymes and metabolism of drugs and neurotoxins within the mammalian brain. ADVANCES IN PHARMACOLOGY (SAN DIEGO, CALIF.) 2022; 95:73-106. [PMID: 35953164 DOI: 10.1016/bs.apha.2022.04.003] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Cytochrome P450 enzymes (CYPs) that metabolize xenobiotics are expressed and active in the brain. These CYPs contribute to the metabolism of many centrally acting compounds, including clinically used drugs, drugs of abuse, and neurotoxins. Although CYP levels are lower in the brain than in the liver, they may influence central substrate and metabolite concentrations, which could alter resulting centrally-mediated responses to these compounds. Additionally, xenobiotic metabolizing CYPs are highly variable due to genetic polymorphisms and regulation by endogenous and xenobiotic molecules. In the brain, these CYPs are sensitive to xenobiotic induction. As a result, CYPs in the brain vary widely, including among humans, and this CYP variation may influence central metabolism and resulting response to centrally acting compounds. It has been demonstrated, using experimental manipulation of CYP activity in vivo selectively within the brain, that CYP metabolism in the brain alters central substrate and metabolite concentrations, as well as drug response and neurotoxic effects. This suggests that variability in xenobiotic metabolizing CYPs in the human brain may meaningfully contribute to individual differences in response to, and effects of, centrally acting drugs and neurotoxins. This chapter will provide an overview of CYP expression in the brain, endogenous- and xenobiotic-mediated CYP regulation, and the functional impact of CYP-mediated metabolism of drugs and neurotoxins in the brain, with a focus on experimental approaches in mice, rats, and non-human primates, and a discussion regarding the potential role of xenobiotic metabolizing CYPs in the human brain.
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Affiliation(s)
- Marlaina R Stocco
- Department of Psychological and Brain Sciences, University of California, Santa Barbara, Santa Barbara, CA, United States
| | - Rachel F Tyndale
- Department of Pharmacology and Toxicology, University of Toronto, Toronto, ON, Canada; Campbell Family Mental Health Research Institute, CAMH, Toronto, ON, Canada; Department of Psychiatry, University of Toronto, Toronto, ON, Canada.
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4
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Sun A, Wang J. Choroid Plexus and Drug Removal Mechanisms. AAPS JOURNAL 2021; 23:61. [PMID: 33942198 DOI: 10.1208/s12248-021-00587-9] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/05/2021] [Accepted: 03/24/2021] [Indexed: 01/08/2023]
Abstract
Timely and efficient removal of xenobiotics and metabolites from the brain is crucial in maintaining the homeostasis and normal function of the brain. The choroid plexus (CP) forms the blood-cerebrospinal fluid barrier and vitally removes drugs and wastes from the brain through several co-existing clearance mechanisms. The CP epithelial (CPE) cells synthesize and secrete the cerebrospinal fluid (CSF). As the CSF passes through the ventricular and subarachnoid spaces and eventually drains into the general circulation, it collects and removes drugs, toxins, and metabolic wastes from the brain. This bulk flow of the CSF serves as a default and non-selective pathway for the removal of solutes and macromolecules from the brain interstitium. Besides clearance by CSF bulk flow, the CPE cells express several multispecific membrane transporters to actively transport substrates from the CSF side into the blood side. In addition, several phase I and II drug-metabolizing enzymes are expressed in the CPE cells, which enzymatically inactivate a broad spectrum of reactive or toxic substances. This review summarizes our current knowledge of the functional characteristics and key contributors to the various clearance pathways in the CP-CSF system, overviewing recent developments in our understanding of CSF flow dynamics and the functional roles of CP uptake and efflux transporters in influencing CSF drug concentrations.
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Affiliation(s)
- Austin Sun
- Department of Pharmaceutics, University of Washington, Health Science Building Room H-272J, Box 357610, Seattle, Washington, 98195-7610, USA
| | - Joanne Wang
- Department of Pharmaceutics, University of Washington, Health Science Building Room H-272J, Box 357610, Seattle, Washington, 98195-7610, USA.
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5
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Cherif LS, Cao-Lei L, Farinelle S, Muller CP, Turner JD, Schroeder H, Grova N. Assessment of 9-OH- and 7,8-diol-benzo[a]pyrene in Blood as Potent Markers of Cognitive Impairment Related to benzo[a]pyrene Exposure: An Animal Model Study. TOXICS 2021; 9:toxics9030050. [PMID: 33800341 PMCID: PMC7998639 DOI: 10.3390/toxics9030050] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/17/2021] [Revised: 02/14/2021] [Accepted: 03/03/2021] [Indexed: 12/27/2022]
Abstract
The potent neurotoxicity of benzo[a]pyrene (B[a]P) has been suggested to be a susceptibility factor accelerating the onset of brain tumours and the emergence of neurobehavioural disturbances. B[a]P has been shown to be neurotoxic, acting directly on both the central and peripheral nervous systems, as well as indirectly via peripheral organs like liver and gut. By using a realistic B[a]P exposure scenario (0.02-200 mg/kg/day, 10 days) in mice, we elucidated brain-specific B[a]P metabolism and at identified hydroxylated B[a]P metabolites in serum which could be used as markers of cognitive impairment. Repeated oral administration of B[a]P led to, at the doses of 20 and 200 mg/kg/day, significant overexpression of Cyp1a1/Cyp1b1 in 2 out of the 3 brain regions considered, thereby suggesting the ability of the brain to metabolize B[a]P itself. At the same doses, mice exhibited a reduction in anxiety in both the elevated plus maze and the hole board apparatus. Concomitantly, B[a]P triggered dose-dependent changes in Nmda subunit expression (Nr1 and Nr2a/Nr2b) in areas involved in cognition. We detected 9-OH-B[a]P and 7,8-diol-B[a]P in serum at the level for which cognitive impairment was observed. We suggest that these metabolites may, in the future be exploited as potent biomarkers of B[a]P-induced cognitive impairments.
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Affiliation(s)
- Lynda Saber Cherif
- Calbinotox, EA7488, Faculty of Science and Technology, Lorraine University, 54500 Vandoeuvre-lès Nancy, France; (L.S.C.); (L.C.-L.); (H.S.)
| | - Lei Cao-Lei
- Calbinotox, EA7488, Faculty of Science and Technology, Lorraine University, 54500 Vandoeuvre-lès Nancy, France; (L.S.C.); (L.C.-L.); (H.S.)
- Immune Endocrine Epigenetics Research Group, Department of Infection and Immunity, LuxembourgInstitute of Health, L-4354 Esch-sur-Alzette, Luxembourg;
| | - Sophie Farinelle
- Experimental & Molecular Immunology Research Group, Department of Infection and Immunity, Luxembourg Institute of Health, L-4354 Esch-sur-Alzette, Luxembourg;
| | - Claude P. Muller
- Department of Infection and Immunity, Luxembourg Institute of Health, L-4354 Esch-Sur-Alzette, Luxembourg;
- Laboratoire National de Santé, L-3583 Dudelange, Luxembourg
| | - Jonathan D. Turner
- Immune Endocrine Epigenetics Research Group, Department of Infection and Immunity, LuxembourgInstitute of Health, L-4354 Esch-sur-Alzette, Luxembourg;
| | - Henri Schroeder
- Calbinotox, EA7488, Faculty of Science and Technology, Lorraine University, 54500 Vandoeuvre-lès Nancy, France; (L.S.C.); (L.C.-L.); (H.S.)
| | - Nathalie Grova
- Calbinotox, EA7488, Faculty of Science and Technology, Lorraine University, 54500 Vandoeuvre-lès Nancy, France; (L.S.C.); (L.C.-L.); (H.S.)
- Immune Endocrine Epigenetics Research Group, Department of Infection and Immunity, LuxembourgInstitute of Health, L-4354 Esch-sur-Alzette, Luxembourg;
- Correspondence: or ; Tel.: +352-26-970-422
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6
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Gorczyca L, Aleksunes LM. Transcription factor-mediated regulation of the BCRP/ ABCG2 efflux transporter: a review across tissues and species. Expert Opin Drug Metab Toxicol 2020; 16:239-253. [PMID: 32077332 DOI: 10.1080/17425255.2020.1732348] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Introduction: The breast cancer resistance protein (BCRP/ABCG2) is a member of the ATP-binding cassette superfamily of transporters. Using the energy garnered from the hydrolysis of ATP, BCRP actively removes drugs and endogenous molecules from the cell. With broad expression across the liver, kidney, brain, placenta, testes, and small intestines, BCRP can impact the pharmacokinetics and pharmacodynamics of xenobiotics.Areas covered: The purpose of this review is to summarize the transcriptional signaling pathways that regulate BCRP expression across various tissues and mammalian species. We will cover the endobiotic- and xenobiotic-activated transcription factors that regulate the expression and activity of BCRP. These include the estrogen receptor, progesterone receptor, peroxisome proliferator-activated receptor, constitutive androstane receptor, pregnane X receptor, nuclear factor e2-related factor 2, and aryl hydrocarbon receptor.Expert opinion: Key transcription factors regulate BCRP expression and function in response to hormones and xenobiotics. Understanding this regulation provides an opportunity to improve pharmacotherapeutic outcomes by enhancing the efficacy and reducing the toxicity of drugs that are substrates of this efflux transporter.
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Affiliation(s)
- Ludwik Gorczyca
- Department of Pharmacology and Toxicology, Rutgers University Ernest Mario School of Pharmacy, Piscataway, NJ, USA
| | - Lauren M Aleksunes
- Department of Pharmacology and Toxicology, Rutgers University Ernest Mario School of Pharmacy, Piscataway, NJ, USA.,Division of Toxicology, Environmental and Occupational Health Sciences Institute, Piscataway, NJ, USA
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7
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Fleming I. New Lipid Mediators in Retinal Angiogenesis and Retinopathy. Front Pharmacol 2019; 10:739. [PMID: 31333461 PMCID: PMC6624440 DOI: 10.3389/fphar.2019.00739] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2019] [Accepted: 06/07/2019] [Indexed: 12/31/2022] Open
Abstract
Retinal diseases associated with vascular destabilization and the inappropriate proliferation of retinal endothelial cells have major consequences on the retinal vascular network. In extreme cases, the development of hypoxia, the upregulation of growth factors, and the hyper-proliferation of unstable capillaries can result in bleeding and vision loss. While anti-vascular endothelial growth factor therapy and laser retinal photocoagulation can be used to treat the symptoms of late stage disease, there is currently no treatment available that can prevent disease progression. Cytochrome P450 enzymes metabolize endogenous substrates (polyunsaturated fatty acids) to bioactive fatty acid epoxides that demonstrate biological activity with generally protective/anti-inflammatory and insulin-sensitizing effects. These epoxides are further metabolized by the soluble epoxide hydrolase (sEH) to fatty acid diols, high concentrations of which have vascular destabilizing effects. Recent studies have identified increased sEH expression and activity and the subsequent generation of the docosahexaenoic acid-derived diol; 19,20-dihydroxydocosapentaenoic acid, as playing a major role in the development of diabetic retinopathy. This review summarizes current understanding of the roles of cytochrome P450 enzyme and sEH–derived PUFA mediators in retinal disease.
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Affiliation(s)
- Ingrid Fleming
- Institute for Vascular Signalling, Centre for Molecular Medicine, Goethe-University, Frankfurt, Germany.,German Centre for Cardiovascular Research (DZHK) partner site RheinMain, Frankfurt, Germany
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8
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Wang Q, Zuo Z. Impact of transporters and enzymes from blood–cerebrospinal fluid barrier and brain parenchyma on CNS drug uptake. Expert Opin Drug Metab Toxicol 2018; 14:961-972. [DOI: 10.1080/17425255.2018.1513493] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Affiliation(s)
- Qianwen Wang
- School of Pharmacy, The Chinese University of Hong Kong, Hong Kong, P. R. China
| | - Zhong Zuo
- School of Pharmacy, The Chinese University of Hong Kong, Hong Kong, P. R. China
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9
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Saili KS, Zurlinden TJ, Schwab AJ, Silvin A, Baker NC, Hunter ES, Ginhoux F, Knudsen TB. Blood-brain barrier development: Systems modeling and predictive toxicology. Birth Defects Res 2018; 109:1680-1710. [PMID: 29251840 DOI: 10.1002/bdr2.1180] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2017] [Accepted: 11/12/2017] [Indexed: 01/17/2023]
Abstract
The blood-brain barrier (BBB) serves as a gateway for passage of drugs, chemicals, nutrients, metabolites, and hormones between vascular and neural compartments in the brain. Here, we review BBB development with regard to the microphysiology of the neurovascular unit (NVU) and the impact of BBB disruption on brain development. Our focus is on modeling these complex systems. Extant in silico models are available as tools to predict the probability of drug/chemical passage across the BBB; in vitro platforms for high-throughput screening and high-content imaging provide novel data streams for profiling chemical-biological interactions; and engineered human cell-based microphysiological systems provide empirical models with which to investigate the dynamics of NVU function. Computational models are needed that bring together kinetic and dynamic aspects of NVU function across gestation and under various physiological and toxicological scenarios. This integration will inform adverse outcome pathways to reduce uncertainty in translating in vitro data and in silico models for use in risk assessments that aim to protect neurodevelopmental health.
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Affiliation(s)
- Katerine S Saili
- National Center for Computational Toxicology (NCCT); U.S. Environmental Protection Agency, Office of Research and Development, Research Triangle Park, North Carolina 27711
| | - Todd J Zurlinden
- National Center for Computational Toxicology (NCCT); U.S. Environmental Protection Agency, Office of Research and Development, Research Triangle Park, North Carolina 27711
| | - Andrew J Schwab
- National Health and Environmental Effects Research Laboratory (NHEERL), U.S. Environmental Protection Agency, Office of Research and Development, Research Triangle Park, North Carolina 27711
| | - Aymeric Silvin
- Singapore Immunology Network (SIgN), Agency for Science, Technology and Research (A*STAR), 138648, Singapore
| | - Nancy C Baker
- Leidos, contractor to NCCT, Research Triangle Park, North Carolina 27711
| | - E Sidney Hunter
- National Health and Environmental Effects Research Laboratory (NHEERL), U.S. Environmental Protection Agency, Office of Research and Development, Research Triangle Park, North Carolina 27711
| | - Florent Ginhoux
- Singapore Immunology Network (SIgN), Agency for Science, Technology and Research (A*STAR), 138648, Singapore
| | - Thomas B Knudsen
- National Center for Computational Toxicology (NCCT); U.S. Environmental Protection Agency, Office of Research and Development, Research Triangle Park, North Carolina 27711
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Kerdelhué B, Forest C, Coumoul X. Dimethyl-Benz(a)anthracene: A mammary carcinogen and a neuroendocrine disruptor. BIOCHIMIE OPEN 2016; 3:49-55. [PMID: 29450131 PMCID: PMC5801823 DOI: 10.1016/j.biopen.2016.09.003] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/08/2016] [Accepted: 09/30/2016] [Indexed: 12/22/2022]
Abstract
Polycyclic Aromatic Hydrocarbons (PAHs) are potent carcinogens. Among these, dimethylbenz(a)anthracene (DMBA) is well known for its capacity to induce mammary carcinomas in female Sprague-Dawley (SD) rats. Ovariectomy suppresses the susceptibility of this model to DMBA, thus suggesting that the inducible action of the carcinogen depends on ovarian hormones. The promotion of DMBA-induced adenocarcinoma is accompanied by a series of neuroendocrine disruptions of both Hypothalamo-Pituitary-Gonadal (HPG) and Hypothalamo-Pituitary-Adrenal (HPA) axes and of the secretion of melatonin during the latency period of 2 months that precedes the occurrence of the first mammary tumor. The present review analyses the various neuroendocrine disruptions that occur along the HPG and the HPA axes, and the marked inhibitory effect of the carcinogen on melatonin secretion. The possible relationships between the neuroendocrine disruptions, which essentially consist in an increased pre-ovulatory secretion of 17β-estradiol and prolactin, associated with a marked reduction of melatonin secretion, and the decrease in gene expression of the receptors for aryl-hydrocarbons receptor (AhR) and 17β-estradiol (ERα; ERβ) are also discussed. Polycyclic Aromatic Hydrocarbons influence promotion of breast tumorigenesis. Dimethylbenz(a)anthracene (DMBA) alters neuroendocrine axes and melatonin secretion. DMBA modulates the activity of aryl hydrocarbon and 17β-estradiol receptors.
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Key Words
- ACTH, Adrenocorticotropic hormone
- ARNT, AhR nuclear translocator
- AhR, Aryl hydrocarbon Receptor
- CRH, Corticotropin releasing hormone
- CYP, Cytochromes P450
- DMBA, Dimethylbenz(a)anthracene
- Dimethylbenz(a)anthracene
- E2, 17β-estradiol
- ERα and ERβ, Estrogen receptor
- FSH, Folliculo-Stimulating Hormone
- Female rat
- GnRH, Gonadotropin-Releasing Hormone
- HPA, Hypothalamo-Pituitary-Adrenal
- HPG, Hypothalamo-Pituitary-Gonadal
- LH, Luteinizing hormone
- Mammary cancer
- Neuroendocrine disruption
- PAHs, Polycyclic Aromatic Hydrocarbons
- PRL, Prolactin
- SD, Sprague-Dawley
- TCDD, 2,3,7,8-tetrachlorodibenzo-p-dioxin
- XRE, Xenobiotic response elements
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Affiliation(s)
- Bernard Kerdelhué
- CNRS UMR 8601, Chimie et Biochimie Pharmacologiques et Toxicologiques, Université Paris Descartes, Faculté des Sciences Fondamentales et Biomédicales, 45 rue des Saints Pères, 75006 Paris, France
- Corresponding author.
| | - Claude Forest
- INSERM UMR-S 1124, Université Paris Descartes, PRES Sorbonne Paris Cité, Pharmacologie Toxicologie et Signalisation Cellulaire, Faculté des Sciences Fondamentales et Biomédicales, 45 rue des Saints Pères, 75006 Paris, France
| | - Xavier Coumoul
- INSERM UMR-S 1124, Université Paris Descartes, PRES Sorbonne Paris Cité, Pharmacologie Toxicologie et Signalisation Cellulaire, Faculté des Sciences Fondamentales et Biomédicales, 45 rue des Saints Pères, 75006 Paris, France
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11
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Ghosh C, Hossain M, Solanki J, Dadas A, Marchi N, Janigro D. Pathophysiological implications of neurovascular P450 in brain disorders. Drug Discov Today 2016; 21:1609-1619. [PMID: 27312874 DOI: 10.1016/j.drudis.2016.06.004] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2016] [Revised: 04/14/2016] [Accepted: 06/06/2016] [Indexed: 01/12/2023]
Abstract
Over the past decades, the significance of cytochrome P450 (CYP) enzymes has expanded beyond their role as peripheral drug metabolizers in the liver and gut. CYP enzymes are also functionally active at the neurovascular interface. CYP expression is modulated by disease states, impacting cellular functions, detoxification, and reactivity to toxic stimuli and brain drug biotransformation. Unveiling the physiological and molecular complexity of brain P450 enzymes will improve our understanding of the mechanisms underlying brain drug availability, pharmacological efficacy, and neurotoxic adverse effects from pharmacotherapy targeting brain disorders.
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Affiliation(s)
- Chaitali Ghosh
- Cerebrovascular Research, Cleveland Clinic Lerner Research Institute, Cleveland, OH, USA; Department of Biomedical Engineering, Cleveland Clinic Lerner Research Institute, Cleveland, OH, USA; Department of Molecular Medicine, Cleveland Clinic Lerner Research Institute, Cleveland, OH, USA.
| | - Mohammed Hossain
- Cerebrovascular Research, Cleveland Clinic Lerner Research Institute, Cleveland, OH, USA; Department of Biomedical Engineering, Cleveland Clinic Lerner Research Institute, Cleveland, OH, USA
| | | | - Aaron Dadas
- The Ohio State University, Columbus, OH, USA
| | - Nicola Marchi
- Cerebrovascular Mechanisms of Brain Disorders, Department of Neuroscience, Institute of Functional Genomics (CNRS/INSERM), Montpellier, France
| | - Damir Janigro
- Flocel Inc. and Case Western Reserve University, Cleveland, OH, USA
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12
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Wiest EF, Warneke A, Walsh MT, Langsfeld M, Anderson J, Walker MK. Association of serum aryl hydrocarbon receptor activity and RBC omega-3 polyunsaturated fatty acids with flow-mediated dilation in healthy, young Hispanic cigarette smokers. Toxicol Lett 2014; 232:422-8. [PMID: 25482063 DOI: 10.1016/j.toxlet.2014.12.002] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2014] [Revised: 11/24/2014] [Accepted: 12/02/2014] [Indexed: 12/17/2022]
Abstract
Impaired flow-mediated dilation (FMD) occurs prior to clinical disease in young cigarette smokers. We investigated two potential biomarkers of FMD: serum aryl hydrocarbon receptor (AHR) activity and RBC omega-3 polyunsaturated fatty acids in healthy young Hispanic cigarette smokers. We recruited never (n=16) and current (n=16) Hispanic smokers (32 ± 7 years old), excluding individuals with clinical cardiovascular disease. We measured FMD with duplex ultrasound, RBC fatty acids and serum AHR activity using a luciferase reporter assay. FMD was significantly impaired in smokers (5.8 ± 4%) versus never smokers (12.3 ± 7.4%, p=0.001). Serum AHR activity was significantly increased in smokers (1467 ± 358 relative light units (RLU)) versus never smokers (689 ± 251 RLU, p<0.001), and correlated positively with FMD only in smokers (r=0.691, p<0.004). RBC percentage of α-linolenic acid (ALA%) was significantly increased in smokers (0.14 ± 0.03%) versus never smokers (0.11 ± 0.03%, p=0.018), and correlated inversely with FMD only in smokers (r=-0.538, p=0.03). The combination of serum AHR activity, ALA%, and systolic blood pressure significantly correlated with FMD in a multivariable regression model (r=0.802, p<0.008). These results suggest that serum AHR activity and RBC ALA% could serve as biomarkers of FMD in healthy, young Hispanic cigarette smokers.
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Affiliation(s)
- Elani F Wiest
- Department of Pharmaceutical Sciences, College of Pharmacy, University of New Mexico, Albuquerque, NM, USA
| | - Alex Warneke
- Vascular Lab, University of New Mexico Hospital, Albuquerque, NM, USA
| | - Mary T Walsh
- Department of Pharmaceutical Sciences, College of Pharmacy, University of New Mexico, Albuquerque, NM, USA
| | - Mark Langsfeld
- Department of Surgery, University of New Mexico, Albuquerque, NM, USA
| | - Joe Anderson
- Department of Pharmacy Practice and Administrative Sciences, College of Pharmacy, University of New Mexico, Albuquerque, NM, USA
| | - Mary K Walker
- Department of Pharmaceutical Sciences, College of Pharmacy, University of New Mexico, Albuquerque, NM, USA.
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13
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Role of brain cytochrome P450 mono-oxygenases in bilirubin oxidation-specific induction and activity. Arch Toxicol 2014; 90:279-90. [DOI: 10.1007/s00204-014-1394-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2014] [Accepted: 10/16/2014] [Indexed: 01/24/2023]
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Agúndez JAG, Jiménez-Jiménez FJ, Alonso-Navarro H, García-Martín E. Drug and xenobiotic biotransformation in the blood-brain barrier: a neglected issue. Front Cell Neurosci 2014; 8:335. [PMID: 25368552 PMCID: PMC4201098 DOI: 10.3389/fncel.2014.00335] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2014] [Accepted: 09/30/2014] [Indexed: 11/13/2022] Open
Abstract
Drug biotransformation is a crucial mechanism for facilitating the elimination of chemicals from the organism and for decreasing their pharmacological activity. Published evidence suggests that brain drug metabolism may play a role in the development of adverse drug reactions and in the clinical response to drugs and xenobiotics. The blood-brain barrier (BBB) has been regarded mainly as a physical barrier for drugs and xenobiotics, and little attention has been paid to the BBB as a drug-metabolizing barrier. The presence of drug-metabolizing enzymes in the BBB is likely to have functional implications because local metabolism may inactivate drugs or may modify the drug's ability to cross the BBB, thus modifying drug response and the risk of developing adverse drug reactions. In this perspective paper, we discuss the expression of relevant xenobiotic metabolizing enzymes in the brain and in the BBB, and we cover current advances and future directions on the potential role of these BBB drug-metabolizing enzymes as modifiers of drug response.
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Affiliation(s)
- José A G Agúndez
- Department of Pharmacology, University of Extremadura Cáceres, Spain ; ISCIII Research Network of Adverse Reactions to Allergens and Drugs Madrid, Spain
| | | | | | - Elena García-Martín
- ISCIII Research Network of Adverse Reactions to Allergens and Drugs Madrid, Spain ; Department of Biochemistry, Molecular Biology and Genetics, University of Extremadura Cáceres, Spain
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Kratzer I, Liddelow SA, Saunders NR, Dziegielewska KM, Strazielle N, Ghersi-Egea JF. Developmental changes in the transcriptome of the rat choroid plexus in relation to neuroprotection. Fluids Barriers CNS 2013; 10:25. [PMID: 23915922 PMCID: PMC3737068 DOI: 10.1186/2045-8118-10-25] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2013] [Accepted: 07/10/2013] [Indexed: 11/10/2022] Open
Abstract
Background The choroid plexuses are the interface between the blood and the cerebrospinal fluid (CSF) contained within the ventricular spaces of the central nervous system. The tight junctions linking adjacent cells of the choroidal epithelium create a physical barrier to paracellular movement of molecules. Multispecific efflux transporters as well as drug-metabolizing and antioxidant enzymes functioning in these cells contribute to a metabolic barrier. These barrier properties reflect a neuroprotective function of the choroid plexus. The choroid plexuses develop early during embryogenesis and provide pivotal control of the internal environment throughout development when the brain is especially vulnerable to toxic insults. Perinatal injuries like hypoxia and trauma, and exposure to drugs or toxic xenobiotics can have serious consequences on neurogenesis and long-term development. The present study describes the developmental expression pattern of genes involved in the neuroprotective functions of the blood–CSF barrier. Methods The transcriptome of rat lateral ventricular choroid plexuses isolated from fifteen-day-old embryos, nineteen-day old fetuses, two-day old pups, and adults was analyzed by a combination of Affymetrix microarrays, Illumina RNA-Sequencing, and quantitative RT-PCR. Results Genes coding for proteins involved in junction formation are expressed early during development. Overall perinatal expression levels of genes involved in drug metabolism and antioxidant mechanisms are similar to, or higher than levels measured in adults. A similar developmental pattern was observed for multispecific efflux transporter genes of the Abc and Slc superfamilies. Expression of all these genes was more variable in choroid plexus from fifteen-day-old embryos. A large panel of transcription factors involved in the xenobiotic- or cell stress-mediated induction of detoxifying enzymes and transporters is also expressed throughout development. Conclusions This transcriptomic analysis suggests relatively well–established neuroprotective mechanisms at the blood-CSF barrier throughout development of the rat. The expression of many transcription factors early in development raises the possibility of additional protection for the vulnerable developing brain, should the fetus or newborn be exposed to drugs or other xenobiotics.
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Affiliation(s)
- Ingrid Kratzer
- Inserm U1028, Lyon Neuroscience Research Center, Neurooncology & Neuroinflammation Team, Lyon-1 University, Lyon F-69000, France.
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Gazzin S, Strazielle N, Tiribelli C, Ghersi-Egea JF. Transport and metabolism at blood-brain interfaces and in neural cells: relevance to bilirubin-induced encephalopathy. Front Pharmacol 2012; 3:89. [PMID: 22629246 PMCID: PMC3355510 DOI: 10.3389/fphar.2012.00089] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2012] [Accepted: 04/25/2012] [Indexed: 01/16/2023] Open
Abstract
Bilirubin, the end-product of heme catabolism, circulates in non-pathological plasma mostly as a protein-bound species. When bilirubin concentration builds up, the free fraction of the molecule increases. Unbound bilirubin then diffuses across blood-brain interfaces (BBIs) into the brain, where it accumulates and exerts neurotoxic effects. In this classical view of bilirubin neurotoxicity, BBIs act merely as structural barriers impeding the penetration of the pigment-bound carrier protein, and neural cells are considered as passive targets of its toxicity. Yet, the role of BBIs in the occurrence of bilirubin encephalopathy appears more complex than being simple barriers to the diffusion of bilirubin, and neural cells such as astrocytes and neurons can play an active role in controlling the balance between the neuroprotective and neurotoxic effects of bilirubin. This article reviews the emerging in vivo and in vitro data showing that transport and metabolic detoxification mechanisms at the blood-brain and blood-cerebrospinal fluid barriers may modulate bilirubin flux across both cellular interfaces, and that these protective functions can be affected in chronic unconjugated hyperbilirubinemia. Then the in vivo and in vitro arguments in favor of the physiological antioxidant function of intracerebral bilirubin are presented, as well as the potential role of transporters such as ABCC1 and metabolizing enzymes such as cytochromes P-450 in setting the cerebral cell- and structure-specific toxicity of bilirubin following hyperbilirubinemia. The relevance of these data to the pathophysiology of bilirubin-induced neurological diseases is discussed.
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Affiliation(s)
- Silvia Gazzin
- Italian Liver Foundation, AREA Science Park Basovizza Trieste, Italy
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Jacob A, Hartz AM, Potin S, Coumoul X, Yousif S, Scherrmann JM, Bauer B, Declèves X. Aryl hydrocarbon receptor-dependent upregulation of Cyp1b1 by TCDD and diesel exhaust particles in rat brain microvessels. Fluids Barriers CNS 2011; 8:23. [PMID: 21867498 PMCID: PMC3180256 DOI: 10.1186/2045-8118-8-23] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2011] [Accepted: 08/25/2011] [Indexed: 12/14/2022] Open
Abstract
Background AhR activates the transcription of several target genes including CYP1B1. Recently, we showed CYP1B1 as the major cytochrome P450 (CYP) enzyme expressed in human brain microvessels. Here, we studied the effect of AhR activation by environmental pollutants on the expression of Cyp1b1 in rat brain microvessels. Methods Expression of AhR and Cyp1b1 was detected in isolated rat brain microvessels. AhR was immunovisualised in brain microvessel endothelial cells. The effect of AhR ligands on Cyp1b1 expression was studied using isolated brain microvessels after ex vivo and/or in vivo exposure to TCDD, heavy hydrocarbons containing diesel exhaust particles (DEP) or Δ9-tetrahydrocannabinol (Δ9-THC). Results After ex vivo exposure to TCDD (a highly potent AhR ligand) for 3 h, Cyp1b1 expression was significantly increased by 2.3-fold in brain microvessels. A single i.p. dose of TCDD also increased Cyp1b1 transcripts (22-fold) and Cyp1b1 protein (2-fold) in rat brain microvessels at 72 h after TCDD. Likewise, DEP treatment (in vivo and ex vivo) strongly induced Cyp1b1 protein in brain microvessels. DEP-mediated Cyp1b1 induction was inhibited by actinomycin D, cycloheximide, or by an AhR antagonist. In contrast, a sub-chronic in vivo treatment with Δ9-THC once daily for 7 seven days had no effect on Cyp1b1 expression Conclusions Our results show that TCDD and DEP strongly induced Cyp1b1 in rat brain microvessels, likely through AhR activation.
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Affiliation(s)
- Aude Jacob
- Neuropsychopharmacologie des addictions (CNRS UMR 8206), Université Paris Descartes, Sorbonne Paris Cité, Faculté de Pharmacie, Paris, France.
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Gao K, Brandt I, Goldstone JV, Jönsson ME. Cytochrome P450 1A, 1B, and 1C mRNA induction patterns in three-spined stickleback exposed to a transient and a persistent inducer. Comp Biochem Physiol C Toxicol Pharmacol 2011; 154:42-55. [PMID: 21354474 PMCID: PMC3560405 DOI: 10.1016/j.cbpc.2011.02.005] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/24/2010] [Revised: 02/16/2011] [Accepted: 02/17/2011] [Indexed: 11/22/2022]
Abstract
Cytochrome P450 1 (CYP1) mRNA induction patterns in three-spined stickleback (Gasterosteus aculeatus) were explored for use in environmental monitoring of aryl hydrocarbon receptor (AHR) agonists. The cDNAs of stickleback CYP1A, CYP1B1, CYP1C1, and CYP1C2 were cloned and their basal and induced expression patterns were determined in the brain, gill, liver and kidney. Also, their induction time courses were compared after waterborne exposure to a transient (indigo) or a persistent (3,3',4,4',5-pentacholorbiphenyl PCB 126) AHR agonist. The cloned stickleback CYP1s exhibited a high amino acid sequence identity compared with their zebrafish orthologs and their constitutive tissue distribution patterns largely agreed with those reported in other species. PCB 126 (100 nM) induced different CYP1 expression patterns in the four tissues, suggesting tissue-specific regulation. Both indigo (1 nM) and PCB 126 (10 nM) induced a strong CYP1 expression in gills. However, while PCB 126 gave rise to a high and persistent induction in gills and liver, induction by indigo was transient in both organs. The number of putative dioxin response elements found in each CYP1 gene promoter roughly reflected the induction levels of the genes. The high responsiveness of CYP1A, CYP1B1, and CYP1C1 observed in several organs suggests that three-spined stickleback is suitable for monitoring of pollution with AHR agonists.
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Affiliation(s)
- Kai Gao
- Department of Environmental Toxicology, Uppsala University, Norbyvägen 18A, SE-752 36 Uppsala, Sweden
| | - Ingvar Brandt
- Department of Environmental Toxicology, Uppsala University, Norbyvägen 18A, SE-752 36 Uppsala, Sweden
| | - Jared V. Goldstone
- Biology Department, Woods Hole Oceanographic Institution, Woods Hole, MA 02543, USA
| | - Maria E. Jönsson
- Department of Environmental Toxicology, Uppsala University, Norbyvägen 18A, SE-752 36 Uppsala, Sweden
- Corresponding author. Tel.: +46 184712608; fax: +46 184716425.
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Wang X, Hawkins BT, Miller DS. Aryl hydrocarbon receptor-mediated up-regulation of ATP-driven xenobiotic efflux transporters at the blood-brain barrier. FASEB J 2010; 25:644-52. [PMID: 21048045 DOI: 10.1096/fj.10-169227] [Citation(s) in RCA: 81] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Many widespread and persistent organic pollutants, e.g., 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), activate the aryl hydrocarbon receptor (AhR), causing it to translocate to the cell nucleus, where it transactivates target genes. AhR's ability to target the blood-brain barrier is essentially unexplored. We show here that exposing isolated rat brain capillaries to 0.05-0.5 nM TCDD roughly doubled transport activity and protein expression of P-glycoprotein, an ATP-driven drug efflux pump and a critical determinant of drug entry into the CNS. These effects were abolished by actinomycin D or cycloheximide or by the AhR antagonists resveratrol and α-naphthoflavone. Brain capillaries from TCDD-dosed rats (1-5 μg/kg, i.p.) exhibited increased transport activity and protein expression of 3 xenobiotic efflux pumps, P-glycoprotein, multidrug resistance-associated protein 2, and breast cancer resistance polypeptide, as well as expression of Cyp1a1 and Cyp1b1, both AhR target genes. Consistent with increased P-glycoprotein expression in capillaries from TCDD-dosed rats, in situ brain perfusion indicated significantly reduced brain accumulation of verapamil, a P-glycoprotein substrate. These findings suggest a new paradigm for the field of environmental toxicology: toxicants acting through AhR to target xenobiotic efflux transporters at the blood-brain barrier and thus reduce brain accumulation of CNS-acting therapeutic drugs.
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Affiliation(s)
- Xueqian Wang
- Laboratory of Toxicology and Pharmacology, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, NC 27709, USA
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Dutheil F, Jacob A, Dauchy S, Beaune P, Scherrmann JM, Declèves X, Loriot MA. ABC transporters and cytochromes P450 in the human central nervous system: influence on brain pharmacokinetics and contribution to neurodegenerative disorders. Expert Opin Drug Metab Toxicol 2010; 6:1161-74. [DOI: 10.1517/17425255.2010.510832] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
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Effect of β-naphthoflavone on AhR-regulated genes (CYP1A1, 1A2, 1B1, 2S1, Nrf2, and GST) and antioxidant enzymes in various brain regions of pig. Toxicology 2009; 265:69-79. [DOI: 10.1016/j.tox.2009.09.010] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2009] [Revised: 09/16/2009] [Accepted: 09/17/2009] [Indexed: 12/30/2022]
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Andersson H, Helmestam M, Zebrowska A, Olovsson M, Brittebo E. Tamoxifen-Induced Adduct Formation and Cell Stress in Human Endometrial Glands. Drug Metab Dispos 2009; 38:200-7. [DOI: 10.1124/dmd.109.029488] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
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Abstract
Recent studies suggest that the function of the blood-brain barrier (BBB) is not static under normal physiologic conditions and is likely altered in neurodegenerative disease. Prevailing thinking about CNS function, and neurodegenerative disease in particular, is neurocentric excluding the impact of factors outside the CNS. This review challenges this perspective and discusses recent reports suggesting the involvement of peripheral factors including toxins and elements of adaptive immunity that may not only play a role in pathogenesis, but also progression of neurodegenerative diseases. Central to this view is neuroinflammation. Several studies indicate that the neuroinflammatory changes that accompany neurodegeneration affect the BBB or its function by altering transport systems, enhancing immune cell entry, or influencing the BBB's role as a signaling interface. Such changes impair the BBB's normal homeostatic function and affect neural activity. Moreover, recent studies reveal that alterations in BBB and its transporters affect the entry of drugs used to treat neurodegenerative diseases. Incorporating BBB compromise and dysfunction into our view of neurodegenerative disease leads to the inclusion of peripheral mediators in its pathogenesis and progression. In addition, this changing view of the BBB raises interesting new therapeutic possibilities for drug delivery as well as treatment strategies designed to reinstate normal barrier function.
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Affiliation(s)
- Paul M Carvey
- Department of Pharmacology, Rush University Medical Center, Chicago, Illinois 60612, USA.
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Dauchy S, Dutheil F, Weaver RJ, Chassoux F, Daumas-Duport C, Couraud PO, Scherrmann JM, De Waziers I, Declèves X. ABC transporters, cytochromes P450 and their main transcription factors: expression at the human blood-brain barrier. J Neurochem 2008; 107:1518-28. [DOI: 10.1111/j.1471-4159.2008.05720.x] [Citation(s) in RCA: 234] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Dauchy S, Miller F, Couraud PO, Weaver RJ, Weksler B, Romero IA, Scherrmann JM, De Waziers I, Declèves X. Expression and transcriptional regulation of ABC transporters and cytochromes P450 in hCMEC/D3 human cerebral microvascular endothelial cells. Biochem Pharmacol 2008; 77:897-909. [PMID: 19041851 DOI: 10.1016/j.bcp.2008.11.001] [Citation(s) in RCA: 141] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2008] [Revised: 11/02/2008] [Accepted: 11/04/2008] [Indexed: 11/26/2022]
Abstract
We investigated the expression of genes encoding ABC transporters, cytochromes P450 (CYPs) and some transcription factors in the hCMEC/D3 immortalized human cerebral microvascular endothelial cell line, a promising in vitro model of the human BBB, and we compared these expressions to a non-brain endothelial cell line (HUVEC) and freshly human brain microvessels. qRT-PCR showed that the MDR1, BCRP, MRP1, MRP3, MRP4 and MRP5 genes were expressed and that the main CYP gene was CYP2U1 in hCMEC/D3. The pattern of ABC and CYPs gene expression in hCMEC/D3 differed from HUVEC which did not express MDR1. Moreover, expression of P-gp and BCRP was lower in hCMEC/D3 than in human brain microvessels but remain functional as shown by rhodamine 123 efflux assay. The gene encoding the aryl hydrocarbon receptor (AhR), a transcription factor that regulates the expression of some ABC and CYPs was highly expressed in hCMEC/D3 and HUVEC, while the pregnane-X-receptor (PXR) and the constitutive androstane receptor (CAR) were barely detected. We investigated the function of the AhR-mediated regulatory pathway in hCMEC/D3 by treating them with the AhR agonist TCDD. The expressions of two AhR-target genes, CYP1A1 and CYP1B1, were increased 26-fold and 28-fold. But the expressions of ABC transporter genes were not significantly altered. We have thus determined the pattern of expression of the genes encoding ABC transporters, CYPs and three transcription factors in hCMEC/D3 and shown that the AhR pathway might afford an original functional transport and metabolic pattern in cerebral endothelial cells that is different from other peripheral endothelial cells.
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Affiliation(s)
- Sandrine Dauchy
- Neuropsychopharmacologie des addictions (CNRS UMR 7157), Université Paris Descartes, Faculté de Pharmacie, Paris, France
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Ramos KS, Moorthy B. Bioactivation of Polycyclic Aromatic Hydrocarbon Carcinogens within the vascular Wall: Implications for Human Atherogenesis. Drug Metab Rev 2008; 37:595-610. [PMID: 16393887 DOI: 10.1080/03602530500251253] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Atherogenesis is a complex pathogenetic process involving a variety of structural and functional deficits within the arterial wall that culminate in the formation of fibrous atherosclerotic plaques. Cigarette smoking is potentially the most remediable contributor to cardiovascular mortality and morbidity. Among the 4000 plus chemicals present in tobacco and tobacco smoke, polycyclic aromatic hydrocarbons (PAHs) have been firmly implicated in the etiology of atherosclerosis in experimental model systems. However, the molecular mechanisms responsible for PAH-induced vascular injury are not well understood. In this review, we have focused on the mechanisms of bioactivation of PAHs in the vas-culature, and the possible role(s) of cytochrome P4501A and 1B enzymes in the formation of PAH-DNA adducts within the vessel wall, a phenomenon that may contribute to the development of atherosclerotic plaques in humans.
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Affiliation(s)
- Kenneth S Ramos
- Department of Biochemistry and Molecular Biology, University of Louisville School of Medicine, Louisville, Kentucky, USA
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Frampton JP, Shuler ML, Shain W, Hynd MR. Biomedical Technologies for in vitro Screening and Controlled Delivery of Neuroactive Compounds. Cent Nerv Syst Agents Med Chem 2008; 8:203-219. [PMID: 19079777 PMCID: PMC2600660 DOI: 10.2174/187152408785699613] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Cell culture models can provide information pertaining to the effective dose, toxiciology, and kinetics, for a variety of neuroactive compounds. However, many in vitro models fail to adequately predict how such compounds will perform in a living organism. At the systems level, interactions between organs can dramatically affect the properties of a compound by alteration of its biological activity or by elimination of it from the body. At the tissue level, interaction between cell types can alter the transport properties of a particular compound, or can buffer its effects on target cells by uptake, processing, or changes in chemical signaling between cells. In any given tissue, cells exist in a three-dimensional environment bounded on all sides by other cells and components of the extracellular matrix, providing kinetics that are dramatically different from the kinetics in traditional two-dimensional cell culture systems. Cell culture analogs are currently being developed to better model the complex transport and processing that occur prior to drug uptake in the CNS, and to predict blood-brain barrier permeability. These approaches utilize microfluidics, hydrogel matrices, and a variety of cell types (including lung epithelial cells, hepatocytes, adipocytes, glial cells, and neurons) to more accurately model drug transport and biological activity. Similar strategies are also being used to control both the spatial and temporal release of therapeutic compounds for targeted treatment of CNS disease.
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Affiliation(s)
- John P Frampton
- Department of Biomedical Sciences, School of Public Health, University at Albany, Albany, NY, USA
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Sanyal MK, Li YL. Deleterious effects of polynuclear aromatic hydrocarbon on blood vascular system of the rat fetus. ACTA ACUST UNITED AC 2007; 80:367-73. [PMID: 17615575 DOI: 10.1002/bdrb.20122] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
BACKGROUND Polynuclear aromatic hydrocarbons (PAH), benzo[alpha]pyrene (B[alpha]P) and 7,12-dimethylbenz[alpha]anthracene (DMBA) are toxic environmental agents distributed widely. The relative deleterious effects of these agents on growth and blood vasculature of fetus and placental tissues of the rat were studied. METHODS Pregnant rats (Day 1 sperm positive) with implantation sites confirmed by laparotomy were treated intraperitoneally (i.p.) on Pregnancy Days 10, 12, and 14 with these agents dissolved in corn oil at cumulated total doses 50, 100, and 200 mg/kg/rat, and control with corn oil only (3-20 dams/group). Fetal growth, tissue hemorrhage, and placental pathology were evaluated by different parameters on Pregnancy Day (PD) 20 in treated and control rats. RESULTS DMBA was relatively more deleterious compared to B[alpha]P indicated by increased lethality and progressive reduction of body weight of the mother with increasing doses. At 200 mg/kg/rat doses of these agents, maternal survival was 45% and 100% and body weight reduced 24% and 52% of controls, respectively. The fetal survival rates in live mothers were similar to that of controls. They induced marked fetal growth retardation and necrosis of placental tissues. B[alpha]P and DMBA produced significant toxicity to differentiating fetal blood vascular system as exhibited by rupture of blood vessels and hemorrhage, especially in the skin, cranial, and brain tissues. CONCLUSIONS Maternal PAH exposure induced placental toxicity and associated adverse fetal development and hemorrhage in different parts of the fetal body, in particular, marked intradermal and cranial hemorrhage, showing that developing fetal blood vasculature is a target of PAH toxicity.
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Affiliation(s)
- Mrinal K Sanyal
- Department of Obstetrics and Gynecology, Yale University Medical School, New Haven, CT, USA.
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Haining RL, Nichols-Haining M. Cytochrome P450-catalyzed pathways in human brain: Metabolism meets pharmacology or old drugs with new mechanism of action? Pharmacol Ther 2007; 113:537-45. [PMID: 17270273 DOI: 10.1016/j.pharmthera.2006.11.005] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2006] [Accepted: 11/21/2006] [Indexed: 02/02/2023]
Abstract
The true importance of cytochrome P450 enzymes, not just in drug metabolism but also in pharmacology, is only beginning to be appreciated. Though originally discovered through their role in the biotransformation of xenobiotics, the P450 enzyme super family is ubiquitous in nature and necessarily evolved around endogenous pathways. The extent of tissue- and cell-specific expression of individual P450 isoforms has led many investigators to hypothesize localized roles in endogenous biochemical pathways for isoforms traditionally thought of as drug-metabolizing. In some cases, direct evidence from humanized transgenic animal models can confirm the degree to which such enzymes modulate endogenous pathways. However, overlapping P450 substrate specificities may mask genetic or biochemical deficiencies, such that many of these reactions appear nonessential. Nonetheless, the drug-induced alteration of local biochemical concentrations in extrahepatic tissues due to metabolism by and inhibition of P450 isoforms has tremendous potential for introducing unexpected pharmacological effects. Nowhere is this truer than in the CNS. On the other hand, if we can harness the power of in silico modeling to create highly specific inhibitors of identified brain isoforms, a novel avenue for drug design using P450 as drug targets may be at hand. This article highlights some notable examples in which the catalytic state of specific P450 isoforms involved in endogenous biochemical reaction pathways are influenced by pharmacological agents. The implications of inhibition of P450-catalzyed oxidation steps that are known or speculated to influence arachadonic acid, cholesterol, and catecholamine neurotransmitters pathways in human brain will be considered.
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Affiliation(s)
- Robert L Haining
- West Virginia University, Department of Basic Pharmaceutical Sciences, Morgantown, WV 26505, United States.
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Abstract
The specialized cerebral microvascular endothelium interacts with the cellular milieu of the brain and extracellular matrix to form a neurovascular unit, one aspect of which is a regulated interface between the blood and central nervous system (CNS). The concept of this blood-brain barrier (BBB) as a dynamically regulated system rather than a static barrier has wide-ranging implications for pathophysiology of the CNS. While in vitro models of the BBB are useful for screening drugs targeted to the CNS and indispensable for studies of cerebral endothelial cell biology, the complex interactions of the neurovascular unit make animal-based models and methods essential tools for understanding the pathophysiology of the BBB. BBB dysfunction is a complication of neurodegenerative disease and brain injury. Studies on animal models have shown that diseases of the periphery, such as diabetes and inflammatory pain, have deleterious effects on the BBB which may contribute to neurological complications associated with these conditions. Furthermore, genetic and/or epigenetic abnormalities in constituents of the BBB may be significant contributing factors in disease etiology. Research that approaches the BBB as a dynamic system integrated with both the CNS and the periphery is therefore critical to understanding and treating diseases of the CNS. Herein, we review various methodological approaches used to study BBB function in the context of disease. These include measurement of transport between blood and brain, imaging-based technologies, and genomic/proteomic approaches.
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Dallas S, Miller DS, Bendayan R. Multidrug Resistance-Associated Proteins: Expression and Function in the Central Nervous System. Pharmacol Rev 2006; 58:140-61. [PMID: 16714484 DOI: 10.1124/pr.58.2.3] [Citation(s) in RCA: 230] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Drug delivery to the brain is highly restricted, since compounds must cross a series of structural and metabolic barriers to reach their final destination, often a cellular compartment such as neurons, microglia, or astrocytes. The primary barriers to the central nervous system are the blood-brain and blood-cerebrospinal fluid barriers. Through structural modifications, including the presence of tight junctions that greatly limit paracellular transport, the cells that make up these barriers restrict diffusion of many pharmaceutically active compounds. In addition, the cells that comprise the blood-brain and blood-cerebrospinal fluid barriers express multiple ATP-dependent, membrane-bound, efflux transporters, such as members of the multidrug resistance-associated protein (MRP) family, which contribute to lowered drug accumulation. A relatively new concept in brain drug distribution just beginning to be explored is the possibility that cellular components of the brain parenchyma could act as a "second" barrier to brain permeation of pharmacological agents via expression of many of the same transporters. Indeed, efflux transporters expressed in brain parenchyma may facilitate the overall export of xenobiotics from the central nervous system, essentially handing them off to the barrier tissues. We propose that these primary and secondary barriers work in tandem to limit overall accumulation and distribution of xenobiotics in the central nervous system. The present review summarizes recent knowledge in this area and emphasizes the clinical significance of MRP transporter expression in a variety of neurological disorders.
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Affiliation(s)
- Shannon Dallas
- Laboratory of Pharmacology and Chemistry, National Institute of Environmental Health Sciences, NIH, Research Triangle Park, NC, USA
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Song P, Meibohm B, Yates CR. LC/MS/MS in drug development: targeting the brain. Biotechniques 2006; Suppl:19-23. [PMID: 16528912 DOI: 10.2144/05386su03] [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: 11/23/2022] Open
Affiliation(s)
- Pengfei Song
- The University of Tennessee Health Science Center, Memphis, TN 38163, USA
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Garrick RA, Woodin BR, Wilson JY, Middlebrooks BL, Stegeman JJ. Cytochrome P4501A is induced in endothelial cell lines from the kidney and lung of the bottlenose dolphin, Tursiops truncatus. AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2006; 76:295-305. [PMID: 16290286 DOI: 10.1016/j.aquatox.2005.10.005] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/03/2005] [Revised: 10/14/2005] [Accepted: 10/15/2005] [Indexed: 05/05/2023]
Abstract
Marine mammals respond to the presence of polycyclic and planar halogenated aromatic hydrocarbons (PAH or PHAH) with the induced expression in endothelium of cytochrome P4501A1, regulated through the aryl hydrocarbon receptor (AHR) transcription factor. Physiological responses in other animals, such as edema and inflammation indicate that the endothelium may be compromised by exposure to AHR agonists, which are ubiquitous in the marine environment. In other mammals and fish the cellular and molecular consequences of exposure to AHR agonists have been elucidated in cultured endothelial cells. We have cultured and characterized cetacean endothelial cells (EC) and used them in induction studies. Endothelial cells were cultured from the lung and kidney of the bottlenose dolphin, Tursiops truncates, and exposed to the AHR agonists beta-naphthoflavone (betaNF) and 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). betaNF (1-3 microM) induced significant increases in CYP1A1 (O-deethylation of 7-ethoxyresorufin to resorufin; EROD) activity to 3.6 and 0.92 pmol/mg/min in lung and kidney EC, respectively. TCDD was more potent than betaNF, and more efficacious, with maximum induction of CYP1A1 activity of 10.1 and 15.2 pmol/mg/min in lung and kidney EC at 3-10 nM TCDD. The differential response indicates that the lung and kidney endothelial cells in culture retain the ability to respond in a selective manner to specific stimuli. Both the molecular mechanisms of induction and the physiological consequences, especially in the vasculature, of toxicant exposure can be studied in this system.
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Affiliation(s)
- Rita Anne Garrick
- Department of Natural Sciences, Fordham University, New York, NY 10023, USA.
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Bussmann UA, Bussmann LE, Barañao JL. An aryl hydrocarbon receptor agonist amplifies the mitogenic actions of estradiol in granulosa cells: evidence of involvement of the cognate receptors. Biol Reprod 2005; 74:417-26. [PMID: 16237154 DOI: 10.1095/biolreprod.105.043901] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
Abstract
The aryl hydrocarbon receptor (AHR) is a ligand-activated transcription factor that, besides mediating toxic responses, may have a central role in ovarian physiology. Studying the actions of AHR ligands on granulosa cells function, we have found that beta-naphthoflavone amplifies the comitogenic actions of FSH and 17beta-estradiol in a dose-dependent manner. This amplification was even greater in cells that overexpress the AHR and was reversed by cotreatment with the AHR antagonist alpha-naphthoflavone, suggesting that this effect is mediated by the AHR. The estrogen receptor is likewise implicated in this phenomenon, because a pure antiestrogen abolished the described synergism. However, the more traditional inhibitory AHR-estrogen receptor interaction was observed on the estrogen response element-driven transcriptional activity. On the other hand, alpha-naphthoflavone inhibited dose-dependently the mitogenic actions of FSH and 17beta-estradiol. Beta-naphthoflavone induced the expression of Cyp1a1 and Cyp1b1 transcripts, two well-characterized AHR-inducible genes that code for hydroxylases that metabolize estradiol to catecholestrogens. Nevertheless, the positive effect of beta-naphthoflavone on proliferation was not caused by increased metabolism of estradiol to catecholestrogens, because these compounds inhibited the hormonally stimulated DNA synthesis. This latter inhibition exerted by catecholestrogens suggests that these hydroxylases would play a regulatory point in granulosa cell proliferation. Our study indicates that AHR ligands modulate the proliferation of rat granulosa cells, and demonstrates for the first time that an agonist of this receptor is able to amplify the comitogenic action of classical hormones through a mechanism that might implicate a positive cross-talk between the AHR and the estrogen receptor pathways.
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Affiliation(s)
- Ursula A Bussmann
- Instituto de Biologia y Medicina Experimental-CONICET, Universidad de Buenos Aires, 1428 Buenos Aires, Argentina
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Abstract
In recent years, there have been several important advancements in the development of neuropeptide therapeutics. Nevertheless, the targeting of peptide drugs to the CNS remains a formidable obstacle. Delivery of peptide drugs is limited by their poor bioavailability to the brain due to low metabolic stability, high clearance by the liver, and the presence of the blood brain barrier (BBB). Multiple strategies have been devised in an attempt to improve peptide drug delivery to the brain, with variable results. In this review, we discuss several of the strategies that have been used to improve both bioavailability and BBB transport, with an emphasis on antibody based vector delivery, useful for large peptides/small proteins, and glycosylation, useful for small peptides. Further development of these delivery methods may finally enable peptide drugs to be useful for the treatment of neurological disease states.
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Affiliation(s)
- Richard D Egleton
- Department of Medical Pharmacology, University of Arizona College of Medicine, Tucson, Arizona 85724, USA.
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Desaulniers D, Xiao GH, Leingartner K, Chu I, Musicki B, Tsang BK. Comparisons of brain, uterus, and liver mRNA expression for cytochrome p450s, DNA methyltransferase-1, and catechol-o-methyltransferase in prepubertal female Sprague-Dawley rats exposed to a mixture of aryl hydrocarbon receptor agonists. Toxicol Sci 2005; 86:175-84. [PMID: 15858227 DOI: 10.1093/toxsci/kfi178] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Non-ortho polychlorinated biphenyls (PCBs), polychlorinated dibenzodioxins (PCDDs), and polychlorinated dibenzofurans (PCDFs) are ubiquitous environmental contaminants that exert their toxicity mostly through activation of the aryl-hydrocarbon receptor (AhR), and are referred to as AhR agonists. The objective was to study, by real time reverse-transcriptase-polymerase chain reaction (RT-PCR), the effects of postnatal exposure to a reconstituted mixture of AhR agonists present in breast milk (3 non-ortho PCBs, 6 PCDDs, and 7 PCDFs, referred to here-in-after as AhRM) on mRNA expression of estrogen receptor (ERalpha), enzymes involved with the metabolism of estrogens [catechol-o-methyltransferase (Comt), cytochrome P450 (Cyp)1A1, 1B1 and 2B1], and DNA methyltransferase-1 (Dnmt1), in brain areas, liver and uterus of immature female rats. Neonates were exposed by gavage during postnatal day (PND) 1-20 with dosages equivalent to 1, 10, 100, and 1000 times the estimated average human exposure level, and were sacrificed at PND 21. None of the end points were affected in uterine cross-sections, or in samples of uterine tissue layers collected by laser capture microdissection. At 1000x, the AhRM reduced Dnmt1 mRNA abundance to 28% and 32% of control in the liver and hypothalamus, respectively. In the brain, Cyp1A1 was increased (409%) but ERalpha was reduced (66%). Similarly, mRNA abundance for Comt isoforms was reduced in the liver (45%) and brain areas (55-70%). AhRM at 100x, the lowest effective dose, exerted a 220% increase in brain cortex Comt [membrane bound (Mb)], a 219% increase in hepatic Cyp1B1, and a 63% decrease in hepatic Comt (soluble (S)+Mb). These results support the possibility that early exposure to environmental contaminants could lead to effects mediated by changes in DNA methylation and/or estrogen metabolism and signaling.
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Affiliation(s)
- D Desaulniers
- Health Canada, Healthy Environments and Consumer Safety Branch, Environmental & Occupational Toxicology Division, Ottawa, Ontario, Canada K1A 0L2.
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Garrick RA, Woodin BR, Stegeman JJ. CYTOCHROME P4501A INDUCED DIFFERENTIALLY IN ENDOTHELIAL CELLS CULTURED FROM DIFFERENT ORGANS OF ANGUILLA ROSTRATA. ACTA ACUST UNITED AC 2005; 41:57-63. [PMID: 15926861 DOI: 10.1290/0409063.1] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Endothelial cells are a structural barrier and an active regulator of many bodily processes. Cytochrome P4501A (CYP1A) activity is induced in the endothelium of teleosts and mammals exposed to lipophilic xenobiotics, such as polycyclic aromatic hydrocarbons, and can have significant consequences for endothelial functions. We exposed cultures of characterized endothelial cells from the heart, kidney, and rete mirabile of the eel, Anguilla rostrata, to aryl hydrocarbon receptor (AhR) agonists. In heart endothelial cells, the maximum response (based on O-deethylation of 7-ethoxyresorufin to resorufin [EROD] activity) to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), 113 pmol/mg/min, was at 1 nM TCDD and the peak response to beta-napthoflavone (betaNF), 135 pmol/mg/min, was at 3 microM betaNF. The maximum response to TCDD in the kidney endothelial cells is 12 pmol/mg/min at 0.3 nM TCDD. The rete mirabile capillary endothelial cells responded minimally or not at all to exposure to TCDD and betaNF. Both the heart and kidney endothelial cells (but not the rete mirabile capillary cells) have a low level of EROD activity (12.7 and 5.2 pmol/mg/min, respectively) in untreated or dimethylsulfoxide-treated cells. The robust response of the heart endothelial cells to induction and the lack of response in the rete mirabile capillary endothelial cells indicate that these cells are a good resource to use to investigate the physiological consequences of AhR agonist exposure and CYP1A induction in different areas of the vasculature.
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Affiliation(s)
- Rita Anne Garrick
- Department of Natural Sciences, Fordham University, 113 W. 60th Street, New York, New York 10023, USA.
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Egleton RD, Davis TP. Development of neuropeptide drugs that cross the blood-brain barrier. Neurotherapeutics 2005. [DOI: 10.1007/bf03206641] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
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Ma X, Idle JR, Krausz KW, Gonzalez FJ. METABOLISM OF MELATONIN BY HUMAN CYTOCHROMES P450. Drug Metab Dispos 2004; 33:489-94. [PMID: 15616152 DOI: 10.1124/dmd.104.002410] [Citation(s) in RCA: 217] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
In humans, the pineal hormone melatonin (MEL) is principally metabolized to 6-hydroxymelatonin (6-HMEL), which is further conjugated with sulfate and excreted in urine. MEL O-demethylation represents a minor reaction. The exact role of individual human cytochromes P450 (P450s) in these pathways has not been established. We used a panel of 11 recombinant human P450 isozymes to investigate for the first time the 6-hydroxylation and O-demethylation of MEL. CYP1A1, CYP1A2, and CYP1B1 all 6-hydroxylated MEL, with CYP2C19 playing a minor role. These reactions were NADPH-dependent. CYP2C19 and, to some extent CYP1A2, O-demethylated MEL. The K(m) (microM) and V(max) (k(cat), pmol min(-1) pmol(-1) P450) for 6-hydroxylation were estimated as 19.2 +/- 2.01 and 6.46 +/- 0.22 (CYP1A1), 25.9 +/- 2.47 and 10.6 +/- 0.32 (CYP1A2), and 30.9 +/- 3.76 and 5.31 +/- 0.21 (CYP1B1). These findings confirm the suggestion of others that CYP1A2 is probably the foremost hepatic P450 in the 6-hydroxylation of MEL and a single report that CYP1A1 is also able to mediate this reaction. However, this is the first time that CYP1B1 has been shown to 6-hydroxylate MEL. The IC50 for the CYP1B1-selective inhibitor (E)-2,4,3',5'-tetramethoxystilbene was estimated to be 30 nM for MEL 6-hydroxylation by recombinant human CYP1B1. Comparison of brain homogenates from wild-type and cyp1b1-null mice revealed that MEL 6-hydroxylation was clearly mediated to a significant degree by CYP1B1. CYP1B1 is not expressed in the liver but has a ubiquitous extrahepatic distribution, and is found at high levels in tissues that also accumulate either MEL or 6-HMEL, such as intestine and cerebral cortex, where it may assist in regulating levels of MEL and 6-HMEL.
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Affiliation(s)
- Xiaochao Ma
- Laboratory of Metabolism, Center for Cancer Research, National Cancer Institute, Bethesda, MD 20892, USA
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Filbrandt CR, Wu Z, Zlokovic B, Opanashuk L, Gasiewicz TA. Presence and functional activity of the aryl hydrocarbon receptor in isolated murine cerebral vascular endothelial cells and astrocytes. Neurotoxicology 2004; 25:605-16. [PMID: 15183014 DOI: 10.1016/j.neuro.2003.08.007] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2003] [Accepted: 07/11/2003] [Indexed: 10/27/2022]
Abstract
Numerous functions regulated by the central nervous system (CNS) are targeted by 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD); however, the cell specific targets and mechanisms of toxicity are unknown. Outside of the brain, the peripheral vascular endothelium has been identified as a significant cellular target of TCDD toxicity resulting in apoptosis, edema, hemorrhaging and vascular dysfunction. Possible effects of TCDD in the vascular endothelium of the CNS have not been examined. Cellular dysfunction in this endothelium may disrupt function of the blood-brain barrier (BBB), which could severely compromise neuronal homeostasis and potentiate neurotoxicity. TCDD toxicity is mediated primarily by the aryl hydrocarbon receptor (AhR), a ligand activated transcription factor that modulates the expression of a large battery of genes. This study examined the presence and functional activity of the AhR in response to TCDD in endothelial cells and astrocytes, the two primary components of the BBB. Primary mouse cortical endothelial cells and astrocytes express the AhR, as shown by immunocytochemical and western blot analyses. AhR activity was assessed by time- and concentration-dependent analyses of CYP1A1 and CYP1B1 protein expression following TCDD treatment. Both CYP1A1 and CYP1B1 proteins were induced in endothelial cells after 4 and 8h, respectively, while only CYP1B1 protein induction was detected in astrocytes after 16h. The CYP450 protein induction was sustained for greater than 72h in both cell types. These changes in protein expression were dependent on AhR activity as indicated by the inhibition of these responses by a receptor antagonist. Together these data indicate endothelial cells and astrocytes are responsive to TCDD through the AhR-mediated pathway and therefore could be targets of toxicity.
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Affiliation(s)
- Carissa R Filbrandt
- Department of Environmental Medicine, University of Rochester School of Medicine and Dentistry, Box EHSC, 575 Elmwood Avenue, Rochester, NY 14642, USA
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Sturk LM, Brock JL, Bagnell CR, Hall JE, Tidwell RR. Distribution and quantitation of the anti-trypanosomal diamidine 2,5-bis(4-amidinophenyl)furan (DB75) and its N-methoxy prodrug DB289 in murine brain tissue. Acta Trop 2004; 91:131-43. [PMID: 15234662 DOI: 10.1016/j.actatropica.2004.03.010] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2004] [Revised: 03/16/2004] [Accepted: 03/24/2004] [Indexed: 11/15/2022]
Abstract
The current epidemic of sleeping sickness, also known as human African trypanosomiasis in sub-Saharan Africa places nearly 60 million people at risk for developing this life threatening infection. Although effective treatments for early-stage sleeping sickness exist, these drugs usually require extended dosing schedules and intravenous administration. New treatments are also needed for cerebral (late) stage trypanosomiasis. 2,5-Bis(4-amidinophenyl)furan (DB75), a pentamidine analog, has potent in vitro and in vivo anti-trypanosomal activity. However, DB75 does not exhibit significant oral bioavailability and has proved to be ineffective against mouse models of late-stage sleeping sickness regardless of administration route. To circumvent the limited oral bioavailability of DB75, an N-methoxy prodrug 2,5-bis(4-amidinophenyl)furan-bis-O-methylamidoxime (DB289) was designed and developed initially as a compound to treat AIDS-related Pneumocystis carinii pneumonia (PCP). Despite excellent oral activity against early-stage sleeping sickness, oral administration of DB289 exhibited limited efficacy in mouse models of late-stage disease. DB289 has recently entered Phase II(b) clinical trials to treat primary-stage sleeping sickness in Central Africa. The current study takes advantage of the innate fluorescence of DB75 and DB289 along with specific and sensitive quantitative analyses to examine plasma and brain distribution of these compounds. Animals were dosed with intravenous DB75, oral DB289, and intravenous DB289. Following intravenous administration, DB75 was readily detectable in whole brain extracts and persisted for long periods. Fluorescence microscopy revealed that DB75 did not penetrate into brain parenchyma, however, but was sequestered within cells lining the blood-brain and blood-cerebrospinal fluid barriers. In contrast, brain tissue of mice treated with oral DB289 exhibited diffuse fluorescence within the brain parenchyma, suggesting that the prodrug was not trapped within blood-brain barrier cells (BBB). However, maximal brain concentrations of the active compound DB75 were very low (13 nmol/mg of tissue at 24 h). Intravenous administration of DB289 resulted in a qualitatively similar fluorescence pattern to oral DB289, indicating again that DB289 and DB75 were present within brain parenchyma, not only in barrier regions. Furthermore, peak DB75 tissue levels were higher (61 nmol/mg of tissue at 24 h) than with oral prodrug. The near five-fold increase in brain levels of DB289 combined with parenchymal localization of compound fluorescence after intravenous administration suggest that the unaltered prodrug penetrates the blood-brain barrier, and may be subject to in situ biotransformation. Intravenous administration of DB289 should be evaluated in mouse models of late-stage sleeping sickness.
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Affiliation(s)
- Lisa M Sturk
- Department of Pathology and Lab. Medicine, CB# 7545, Room 805, Brinkhous-Bullitt Building, School of Medicine, Chapel Hill, NC 27599, USA
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