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Canlas J, Myers AL. Interactions of Betel Quid Constituents with Drug Disposition Pathways: An Overview. Curr Drug Metab 2023; 24:92-105. [PMID: 36852799 PMCID: PMC11271041 DOI: 10.2174/1389200224666230228142052] [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: 07/18/2022] [Revised: 01/10/2023] [Accepted: 01/25/2023] [Indexed: 03/01/2023]
Abstract
Global estimates indicate that over 600 million individuals worldwide consume the areca (betel) nut in some form. Nonetheless, its consumption is associated with a myriad of oral and systemic ailments, such as precancerous oral lesions, oropharyngeal cancers, liver toxicity and hepatic carcinoma, cardiovascular distress, and addiction. Users commonly chew slivers of areca nut in a complex consumable preparation called betel quid (BQ). Consequently, the user is exposed to a wide array of chemicals with diverse pharmacokinetic behavior in the body. However, a comprehensive understanding of the metabolic pathways significant to BQ chemicals is lacking. Henceforth, we performed a literature search to identify prominent BQ constituents and examine each chemical's interplay with drug disposition proteins. In total, we uncovered over 20 major chemicals (e.g., arecoline, nicotine, menthol, quercetin, tannic acid) present in the BQ mixture that were substrates, inhibitors, and/or inducers of various phase I (e.g., CYP, FMO, hydrolases) and phase II (e.g., GST, UGT, SULT) drug metabolizing enzymes, along with several transporters (e.g., P-gp, BCRP, MRP). Altogether, over 80 potential interactivities were found. Utilizing this new information, we generated theoretical predictions of drug interactions precipitated by BQ consumption. Data suggests that BQ consumers are at risk for drug interactions (and possible adverse effects) when co-ingesting other substances (multiple therapeutic classes) with overlapping elimination mechanisms. Until now, prediction about interactions is not widely known among BQ consumers and their clinicians. Further research is necessary based on our speculations to elucidate the biological ramifications of specific BQ-induced interactions and to take measures that improve the health of BQ consumers.
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Affiliation(s)
- Jasmine Canlas
- Department of Pharmaceutical & Biomedical Sciences, The University of Georgia, Athens, GA 30602, United States
| | - Alan L. Myers
- Department of Diagnostic & Biomedical Sciences, School of Dentistry, The University of Texas Health Science Center at Houston, Houston, TX, 77030, United States
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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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3
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Abstract
The regulation of brain cytochrome P450 enzymes (CYPs) is different compared with respective hepatic enzymes. This may result from anatomical bases and physiological functions of the two organs. The brain is composed of a variety of functional structures built of different interconnected cell types endowed with specific receptors that receive various neuronal signals from other brain regions. Those signals activate transcription factors or alter functioning of enzyme proteins. Moreover, the blood-brain barrier (BBB) does not allow free penetration of all substances from the periphery into the brain. Differences in neurotransmitter signaling, availability to endogenous and exogenous active substances, and levels of transcription factors between neuronal and hepatic cells lead to differentiated expression and susceptibility to the regulation of CYP genes in the brain and liver. Herein, we briefly describe the CYP enzymes of CYP1-3 families, their distribution in the brain, and discuss brain-specific regulation of CYP genes. In parallel, a comparison to liver CYP regulation is presented. CYP enzymes play an essential role in maintaining the levels of bioactive molecules within normal ranges. These enzymes modulate the metabolism of endogenous neurochemicals, such as neurosteroids, dopamine, serotonin, melatonin, anandamide, and exogenous substances, including psychotropics, drugs of abuse, neurotoxins, and carcinogens. The role of these enzymes is not restricted to xenobiotic-induced neurotoxicity, but they are also involved in brain physiology. Therefore, it is crucial to recognize the function and regulation of CYP enzymes in the brain to build a foundation for future medicine and neuroprotection and for personalized treatment of brain diseases.
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Affiliation(s)
- Wojciech Kuban
- Department of Pharmacokinetics and Drug Metabolism, Maj Institute of Pharmacology, Polish Academy of Sciences, Kraków, Poland
| | - Władysława Anna Daniel
- Department of Pharmacokinetics and Drug Metabolism, Maj Institute of Pharmacology, Polish Academy of Sciences, Kraków, Poland
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Bhattacharya C, Kirby D, Van Stipdonk M, Stratford RE. Comparison of In Vitro Stereoselective Metabolism of Bupropion in Human, Monkey, Rat, and Mouse Liver Microsomes. Eur J Drug Metab Pharmacokinet 2019; 44:261-274. [PMID: 30298475 DOI: 10.1007/s13318-018-0516-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
BACKGROUND AND OBJECTIVES Bupropion is an atypical antidepressant and smoking cessation aid associated with wide intersubject variability. This study compared the formation kinetics of three phase I metabolites (hydroxybupropion, threohydrobupropion, and erythrohydrobupropion) in human, marmoset, rat, and mouse liver microsomes. The objective was to establish suitability and limitations for subsequent use of nonclinical species to model bupropion central nervous system (CNS) disposition in humans. METHODS Hepatic microsomal incubations were conducted separately for the R- and S-bupropion enantiomers, and the formation of enantiomer-specific metabolites was determined using LC-MS/MS. Intrinsic formation clearance (CLint) of metabolites across the four species was determined from the formation rate versus substrate concentration relationship. RESULTS The total clearance of S-bupropion was higher than that of R-bupropion in monkey and human liver microsomes. The contribution of hydroxybupropion to the total racemic bupropion clearance was 38%, 62%, 17%, and 96% in human, monkey, rat, and mouse, respectively. In the same species order, threohydrobupropion contributed 53%, 23%, 17%, and 3%, and erythrohydrobupropion contributed 9%, 14%, 66%, and 1.3%, respectively, to racemic bupropion clearance. CONCLUSION The results demonstrate that phase I metabolism in monkeys best approximates that observed in humans, and support the preferred use of this species to investigate possible pharmacokinetic factors that influence the CNS disposition of bupropion and contribute to its high intersubject variability.
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Affiliation(s)
- Chandrali Bhattacharya
- Graduate School of Pharmaceutical Sciences, Duquesne University, 600 Forbes Avenue, Pittsburgh, PA, 15282, USA.,Department of Pharmacy Practice, Purdue University, Indianapolis, IN, 46202, USA
| | - Danielle Kirby
- Department of Chemistry and Biochemistry, Duquesne University, 600 Forbes Avenue, Pittsburgh, PA, 15282, USA
| | - Michael Van Stipdonk
- Department of Chemistry and Biochemistry, Duquesne University, 600 Forbes Avenue, Pittsburgh, PA, 15282, USA
| | - Robert E Stratford
- Graduate School of Pharmaceutical Sciences, Duquesne University, 600 Forbes Avenue, Pittsburgh, PA, 15282, USA. .,Indiana University School of Medicine, Research II, Suite 480, 950 W. Walnut St, Indianapolis, IN, 46202-5188, USA. .,Division of Clinical Pharmacology, Department of Medicine, Indiana University School of Medicine, Indianapolis, IN, 46202, USA.
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McMillan DM, Tyndale RF. CYP-mediated drug metabolism in the brain impacts drug response. Pharmacol Ther 2018; 184:189-200. [DOI: 10.1016/j.pharmthera.2017.10.008] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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Garcia KLP, Lê AD, Tyndale RF. Brain CYP2B induction can decrease nicotine levels in the brain. Addict Biol 2017; 22:1257-1266. [PMID: 27230546 DOI: 10.1111/adb.12411] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2016] [Revised: 03/20/2016] [Accepted: 04/21/2016] [Indexed: 01/07/2023]
Abstract
Nicotine can be metabolized by the enzyme CYP2B; brain CYP2B is higher in rats and monkeys treated with nicotine, and in human smokers. A 7-day nicotine treatment increased CYP2B expression in rat brain but not liver, and decreased the behavioral response and brain levels (ex vivo) to the CYP2B substrate propofol. However, the effect of CYP2B induction on the time course and levels of circulating brain nicotine in vivo has not been demonstrated. Using brain microdialysis, nicotine levels following a subcutaneous nicotine injection were measured on day one and after a 7-day nicotine treatment. There was a significant time x treatment interaction (p = 0.01); peak nicotine levels (15-45 minutes post-injection) were lower after treatment (p = 0.04) consistent with CYP2B induction. Following a two-week washout period, brain nicotine levels increased to day one levels (p = 0.02), consistent with brain CYP2B levels returning to baseline. Brain pretreatment of the CYP2B inhibitor, C8-xanthate, increased brain nicotine levels acutely and after 7-day nicotine treatment, indicating the alterations in brain nicotine levels were due to changes in brain CYP2B activity. Plasma nicotine levels were not altered for any time or treatment sampled, confirming no effect on peripheral nicotine metabolism. These results demonstrate that chronic nicotine, by increasing brain CYP2B activity, reduces brain nicotine levels, which could alter nicotine's reinforcing effects. Higher brain CYP2B levels in smokers could lower brain nicotine levels; as this induction would occur following continued nicotine exposure it could increase withdrawal symptoms and contribute to sustaining smoking behavior.
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Affiliation(s)
- Kristine L. P. Garcia
- Departments of Pharmacology and Toxicology and Psychiatry; Toronto Ontario Canada
- Campbell Family Mental Health Research Institute; Centre for Addiction and Mental Health; Toronto Ontario Canada
| | - Anh Dzung Lê
- Departments of Pharmacology and Toxicology and Psychiatry; Toronto Ontario Canada
- Campbell Family Mental Health Research Institute; Centre for Addiction and Mental Health; Toronto Ontario Canada
| | - Rachel F. Tyndale
- Departments of Pharmacology and Toxicology and Psychiatry; Toronto Ontario Canada
- Campbell Family Mental Health Research Institute; Centre for Addiction and Mental Health; Toronto Ontario Canada
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Subacute nicotine co-exposure has no effect on 2,2',3,5',6- pentachlorobiphenyl disposition but alters hepatic cytochrome P450 expression in the male rat. Toxicology 2015; 338:59-68. [PMID: 26463278 DOI: 10.1016/j.tox.2015.10.002] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2015] [Revised: 09/30/2015] [Accepted: 10/06/2015] [Indexed: 01/09/2023]
Abstract
Polychlorinated biphenyls (PCBs) are metabolized by cytochrome P450 2B enzymes (CYP2B) and nicotine is reported to alter CYP2B activity in the brain and liver. To test the hypothesis that nicotine influences PCB disposition, 2,2',3,5',6-pentachlorobiphenyl (PCB 95) and its metabolites were quantified in tissues of adult male Wistar rats exposed to PCB 95 (6mg/kg/d, p.o.) in the absence or presence of nicotine (1.0mg/kg/d of the tartrate salt, s.c.) for 7 consecutive days. PCB 95 was enantioselectively metabolized to hydroxylated (OH-) PCB metabolites, resulting in a pronounced enrichment of E1-PCB 95 in all tissues investigated. OH-PCBs were detected in blood and liver tissue, but were below the detection limit in adipose, brain and muscle tissues. Co-exposure to nicotine did not change PCB 95 disposition. CYP2B1 mRNA and CYP2B protein were not detected in brain tissues but were detected in liver. Co-exposure to nicotine and PCB 95 increased hepatic CYP2B1 mRNA but did not change CYP2B protein levels relative to vehicle control animals. However, hepatic CYP2B protein in animals co-exposed to PCB 95 and nicotine were reduced compared to animals that received only nicotine. Quantification of CYP2B3, CYP3A2 and CYP1A2 mRNA identified significant effects of nicotine and PCB 95 co-exposure on hepatic CYP3A2 and hippocampal CYP1A2 transcripts. Our findings suggest that nicotine co-exposure does not significantly influence PCB 95 disposition in the rat. However, these studies suggest a novel influence of PCB 95 and nicotine co-exposure on hepatic cytochrome P450 (P450) expression that may warrant further attention due to the increasing use of e-cigarettes and related products.
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Foti RS, Tyndale RF, Garcia KLP, Sweet DH, Nagar S, Sharan S, Rock DA. "Target-Site" Drug Metabolism and Transport. Drug Metab Dispos 2015; 43:1156-68. [PMID: 25986849 PMCID: PMC11024933 DOI: 10.1124/dmd.115.064576] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2015] [Accepted: 05/18/2015] [Indexed: 04/20/2024] Open
Abstract
The recent symposium on "Target-Site" Drug Metabolism and Transport that was sponsored by the American Society for Pharmacology and Experimental Therapeutics at the 2014 Experimental Biology meeting in San Diego is summarized in this report. Emerging evidence has demonstrated that drug-metabolizing enzyme and transporter activity at the site of therapeutic action can affect the efficacy, safety, and metabolic properties of a given drug, with potential outcomes including altered dosing regimens, stricter exclusion criteria, or even the failure of a new chemical entity in clinical trials. Drug metabolism within the brain, for example, can contribute to metabolic activation of therapeutic drugs such as codeine as well as the elimination of potential neurotoxins in the brain. Similarly, the activity of oxidative and conjugative drug-metabolizing enzymes in the lung can have an effect on the efficacy of compounds such as resveratrol. In addition to metabolism, the active transport of compounds into or away from the site of action can also influence the outcome of a given therapeutic regimen or disease progression. For example, organic anion transporter 3 is involved in the initiation of pancreatic β-cell dysfunction and may have a role in how uremic toxins enter pancreatic β-cells and ultimately contribute to the pathogenesis of gestational diabetes. Finally, it is likely that a combination of target-specific metabolism and cellular internalization may have a significant role in determining the pharmacokinetics and efficacy of antibody-drug conjugates, a finding which has resulted in the development of a host of new analytical methods that are now used for characterizing the metabolism and disposition of antibody-drug conjugates. Taken together, the research summarized herein can provide for an increased understanding of potential barriers to drug efficacy and allow for a more rational approach for developing safe and effective therapeutics.
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Affiliation(s)
- Robert S Foti
- Amgen Pharmacokinetics and Drug Metabolism, Seattle, Washington (R.S.F., D.A.R.); Departments of Pharmacology and Toxicology and Psychiatry, Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, University of Toronto, Toronto, Ontario, Canada (R.F.T., K.L.P.G.); Department of Pharmaceutics, School of Pharmacy, Virginia Commonwealth University, Richmond, Virginia (D.H.S.); School of Pharmacy, Temple University, Philadelphia, Pennsylvania (S.N.); and College of Pharmacy, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma (S.S.)
| | - Rachel F Tyndale
- Amgen Pharmacokinetics and Drug Metabolism, Seattle, Washington (R.S.F., D.A.R.); Departments of Pharmacology and Toxicology and Psychiatry, Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, University of Toronto, Toronto, Ontario, Canada (R.F.T., K.L.P.G.); Department of Pharmaceutics, School of Pharmacy, Virginia Commonwealth University, Richmond, Virginia (D.H.S.); School of Pharmacy, Temple University, Philadelphia, Pennsylvania (S.N.); and College of Pharmacy, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma (S.S.)
| | - Kristine L P Garcia
- Amgen Pharmacokinetics and Drug Metabolism, Seattle, Washington (R.S.F., D.A.R.); Departments of Pharmacology and Toxicology and Psychiatry, Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, University of Toronto, Toronto, Ontario, Canada (R.F.T., K.L.P.G.); Department of Pharmaceutics, School of Pharmacy, Virginia Commonwealth University, Richmond, Virginia (D.H.S.); School of Pharmacy, Temple University, Philadelphia, Pennsylvania (S.N.); and College of Pharmacy, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma (S.S.)
| | - Douglas H Sweet
- Amgen Pharmacokinetics and Drug Metabolism, Seattle, Washington (R.S.F., D.A.R.); Departments of Pharmacology and Toxicology and Psychiatry, Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, University of Toronto, Toronto, Ontario, Canada (R.F.T., K.L.P.G.); Department of Pharmaceutics, School of Pharmacy, Virginia Commonwealth University, Richmond, Virginia (D.H.S.); School of Pharmacy, Temple University, Philadelphia, Pennsylvania (S.N.); and College of Pharmacy, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma (S.S.)
| | - Swati Nagar
- Amgen Pharmacokinetics and Drug Metabolism, Seattle, Washington (R.S.F., D.A.R.); Departments of Pharmacology and Toxicology and Psychiatry, Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, University of Toronto, Toronto, Ontario, Canada (R.F.T., K.L.P.G.); Department of Pharmaceutics, School of Pharmacy, Virginia Commonwealth University, Richmond, Virginia (D.H.S.); School of Pharmacy, Temple University, Philadelphia, Pennsylvania (S.N.); and College of Pharmacy, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma (S.S.)
| | - Satish Sharan
- Amgen Pharmacokinetics and Drug Metabolism, Seattle, Washington (R.S.F., D.A.R.); Departments of Pharmacology and Toxicology and Psychiatry, Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, University of Toronto, Toronto, Ontario, Canada (R.F.T., K.L.P.G.); Department of Pharmaceutics, School of Pharmacy, Virginia Commonwealth University, Richmond, Virginia (D.H.S.); School of Pharmacy, Temple University, Philadelphia, Pennsylvania (S.N.); and College of Pharmacy, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma (S.S.)
| | - Dan A Rock
- Amgen Pharmacokinetics and Drug Metabolism, Seattle, Washington (R.S.F., D.A.R.); Departments of Pharmacology and Toxicology and Psychiatry, Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, University of Toronto, Toronto, Ontario, Canada (R.F.T., K.L.P.G.); Department of Pharmaceutics, School of Pharmacy, Virginia Commonwealth University, Richmond, Virginia (D.H.S.); School of Pharmacy, Temple University, Philadelphia, Pennsylvania (S.N.); and College of Pharmacy, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma (S.S.)
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Vichi S, Sandström von Tobel J, Gemma S, Stanzel S, Kopp-Schneider A, Monnet-Tschudi F, Testai E, Zurich MG. Cell type-specific expression and localization of cytochrome P450 isoforms in tridimensional aggregating rat brain cell cultures. Toxicol In Vitro 2015; 30:176-84. [PMID: 25795400 DOI: 10.1016/j.tiv.2015.03.005] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2014] [Revised: 02/04/2015] [Accepted: 03/06/2015] [Indexed: 02/05/2023]
Abstract
Within the Predict-IV FP7 project a strategy for measurement of in vitro biokinetics was developed, requiring the characterization of the cellular model used, especially regarding biotransformation, which frequently depends on cytochrome P450 (CYP) activity. The extrahepatic in situ CYP-mediated metabolism is especially relevant in target organ toxicity. In this study, the constitutive mRNA levels and protein localization of different CYP isoforms were investigated in 3D aggregating brain cell cultures. CYP1A1, CYP2B1/B2, CYP2D2/4, CYP2E1 and CYP3A were expressed; CYP1A1 and 2B1 represented almost 80% of the total mRNA content. Double-immunolabeling revealed their presence in astrocytes, in neurons, and to a minor extent in oligodendrocytes, confirming the cell-specific localization of CYPs in the brain. These results together with the recently reported formation of an amiodarone metabolite following repeated exposure suggest that this cell culture system possesses some metabolic potential, most likely contributing to its high performance in neurotoxicological studies and support the use of this model in studying brain neurotoxicity involving mechanisms of toxication/detoxication.
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Affiliation(s)
- S Vichi
- Istituto Superiore di Sanità, Environment and Primary Prevention Department, Mechanisms of Toxicity Unit, Rome, Italy.
| | - J Sandström von Tobel
- Department of Physiology, University of Lausanne, Lausanne, Switzerland; Swiss Center for Applied Human Toxicology (SCAHT), Switzerland
| | - S Gemma
- Istituto Superiore di Sanità, Environment and Primary Prevention Department, Mechanisms of Toxicity Unit, Rome, Italy
| | - S Stanzel
- Department of Biostatistics, German Cancer Research Center, Heidelberg, Germany
| | - A Kopp-Schneider
- Department of Biostatistics, German Cancer Research Center, Heidelberg, Germany
| | - F Monnet-Tschudi
- Department of Physiology, University of Lausanne, Lausanne, Switzerland; Swiss Center for Applied Human Toxicology (SCAHT), Switzerland
| | - E Testai
- Istituto Superiore di Sanità, Environment and Primary Prevention Department, Mechanisms of Toxicity Unit, Rome, Italy
| | - M G Zurich
- Department of Physiology, University of Lausanne, Lausanne, Switzerland; Swiss Center for Applied Human Toxicology (SCAHT), Switzerland
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Khokhar JY, Tyndale RF. Intracerebroventricularly and Systemically Delivered Inhibitor of Brain CYP2B (C8-Xanthate), Even Following Chlorpyrifos Exposure, Reduces Chlorpyrifos Activation and Toxicity in Male Rats. Toxicol Sci 2014; 140:49-60. [DOI: 10.1093/toxsci/kfu075] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Ande A, McArthur C, Kumar A, Kumar S. Tobacco smoking effect on HIV-1 pathogenesis: role of cytochrome P450 isozymes. Expert Opin Drug Metab Toxicol 2013; 9:1453-64. [PMID: 23822755 PMCID: PMC4007120 DOI: 10.1517/17425255.2013.816285] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
INTRODUCTION Tobacco smoking is highly prevalent among the HIV-1-infected population. In addition to diminished immune response, smoking has been shown to increase HIV-1 replication and decrease response to antiretroviral therapy, perhaps through drug-drug interaction. However, the mechanism by which tobacco/nicotine increases HIV-1 replication and mediates drug-drug interaction is poorly understood. AREAS COVERED In this review, the authors discuss the effects of smoking on HIV-1 pathogenesis. Since they propose a role for the cytochrome P450 (CYP) pathway in smoking-mediated HIV-1 pathogenesis, the authors briefly converse the role of CYP enzymes in tobacco-mediated oxidative stress and toxicity. Finally, the authors focus on the role of CYP enzymes, especially CYP2A6, in tobacco/nicotine metabolism and oxidative stress in HIV-1 model systems monocytes/macrophages, lymphocytes, astrocytes and neurons, which may be responsible for HIV-1 pathogenesis. EXPERT OPINION Recent findings suggest that CYP-mediated oxidative stress is a novel pathway that may be involved in smoking-mediated HIV-1 pathogenesis, including HIV-1 replication and drug-drug interaction. Thus, CYP and CYP-associated oxidative stress pathways may be potential targets to develop novel pharmaceuticals for HIV-1-infected smokers. Since HIV-1/TB co-infections are common, future study involving interactions between antiretroviral and antituberculosis drugs that involve CYP pathways would also help treat HIV-1/TB co-infected smokers effectively.
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Affiliation(s)
- Anusha Ande
- University of Missouri Kansas City, School of Pharmacy, Division of Pharmacology & Toxicology, Kansas City, MO 64108, USA
| | - Carole McArthur
- Professor, University of Missouri Kansas City, School of Dentistry, Department of Oral Biology, Kansas City, MO 64108, USA
| | - Anil Kumar
- Professor and Chair, University of Missouri Kansas City, School of Pharmacy, Division of Pharmacology & Toxicology, Kansas City, MO 64108, USA
| | - Santosh Kumar
- Assistant Professor, University of Missouri Kansas City, School of Pharmacy, Division of Pharmacology & Toxicology, 2464 Charlotte St. Kansas City, MO 64108, USA Tel: +1 816 235 5494 (Off); Fax: +1 816 235 1776;
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12
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Abstract
Cytochrome P450 enzymes (CYPs) metabolize many drugs that act on the central nervous system (CNS), such as antidepressants and antipsychotics; drugs of abuse; endogenous neurochemicals, such as serotonin and dopamine; neurotoxins; and carcinogens. This takes place primarily in the liver, but metabolism can also occur in extrahepatic organs, including the brain. This is important for CNS-acting drugs, as variation in brain CYP-mediated metabolism may be a contributing factor when plasma levels do not predict drug response. This review summarizes the characterization of CYPs in the brain, using examples from the CYP2 subfamily, and discusses sources of variation in brain CYP levels and metabolism. Some recent experiments are described that demonstrate how changes in brain CYP metabolism can influence drug response, toxicity and drug-induced behaviours. Advancing knowledge of brain CYP-mediated metabolism may help us understand why patients respond differently to drugs used in psychiatry and predict risk for psychiatric disorders, including neurodegenerative diseases and substance abuse.
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Affiliation(s)
| | - Rachel F. Tyndale
- Correspondence to: R.F. Tyndale, Department of Pharmacology and Toxicology, 1 King’s College Circle, Toronto ON M5S 1A8;
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13
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Ande A, Earla R, Jin M, Silverstein PS, Mitra AK, Kumar A, Kumar S. An LC-MS/MS method for concurrent determination of nicotine metabolites and the role of CYP2A6 in nicotine metabolite-mediated oxidative stress in SVGA astrocytes. Drug Alcohol Depend 2012; 125:49-59. [PMID: 22498344 PMCID: PMC3413753 DOI: 10.1016/j.drugalcdep.2012.03.015] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/04/2011] [Revised: 03/15/2012] [Accepted: 03/16/2012] [Indexed: 11/28/2022]
Abstract
BACKGROUND Nicotine is known to generate oxidative stress through cytochrome P450 2A6 (CYP2A6)-mediated metabolism in the liver and other organs, including macrophages. This study has been designed to examine the role of CYP2A6 in nicotine metabolism and oxidative stress in SVGA cells, an immortalized human astrocyte cell line. METHODS SVGA astrocytes were treated with 1 μM nicotine, followed by determination of mRNA and protein levels of several CYPs using quantitative RT-PCR and western blot analyses, respectively. Quantitation of nicotine and the nicotine metabolites, cotinine and nicotine-derived nitrosamine ketones (NNK), was performed using an LC-MS/MS method. The generation of reactive oxygen species (ROS) was measured using flow cytometry. RESULTS Nicotine significantly upregulated mRNA and protein expression of the most abundantly expressed CYPs in SVGA astrocytes, CYP2A6 and CYP1A1. To characterize the metabolism of nicotine in astrocytes, a highly sensitive LC-MS/MS method was developed which is capable of quantifying very low concentrations of nicotine (0.3 ng/mL), cotinine and NNK (0.11 ng/mL). The LC-MS/MS results showed that nicotine is steadily metabolized to cotinine and NNK from 0.5 to 4h. Finally, we showed that nicotine initially causes an increase in ROS formation which is then gradually decreased, perhaps due to the increase in superoxide dismutase level. Nicotine metabolism and ROS formation by CYP2A6 were further confirmed by using tryptamine, a selective inhibitor of CYP2A6, which significantly lowered the levels of cotinine and NNK and inhibited ROS formation. CONCLUSIONS CYP2A6 plays a key role in nicotine metabolism and oxidative stress in astrocytes, and this has implications in nicotine-associated brain toxicity.
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Affiliation(s)
- Anusha Ande
- Pharmacology and Toxicology, School of Pharmacy, 3253 Health Sciences Building, University of Missouri-Kansas City, 2464 Charlotte Street, Kansas City, MO 64108, USA
| | - Ravinder Earla
- Pharmaceutical Sciences, School of Pharmacy, 5258 Health Sciences Building, University of Missouri-Kansas City, 2464 Charlotte Street, Kansas City, MO 64108, USA
| | - Mengyao Jin
- Pharmacology and Toxicology, School of Pharmacy, 3253 Health Sciences Building, University of Missouri-Kansas City, 2464 Charlotte Street, Kansas City, MO 64108, USA
| | - Peter S Silverstein
- Pharmacology and Toxicology, School of Pharmacy, 3253 Health Sciences Building, University of Missouri-Kansas City, 2464 Charlotte Street, Kansas City, MO 64108, USA
| | - Ashim K Mitra
- Pharmaceutical Sciences, School of Pharmacy, 5258 Health Sciences Building, University of Missouri-Kansas City, 2464 Charlotte Street, Kansas City, MO 64108, USA
| | - Anil Kumar
- Pharmacology and Toxicology, School of Pharmacy, 3253 Health Sciences Building, University of Missouri-Kansas City, 2464 Charlotte Street, Kansas City, MO 64108, USA
| | - Santosh Kumar
- Pharmacology and Toxicology, School of Pharmacy, 3253 Health Sciences Building, University of Missouri-Kansas City, 2464 Charlotte Street, Kansas City, MO 64108, USA,Corresponding author: Division of Pharmacology and Toxicology, School of Pharmacy, University of Missouri-Kansas City, 2464 Charlotte St. Kansas City, MO 64108, USA Phone: 816-235-5494, Fax: 816-235-1776,
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14
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Beltrán-Ramírez O, Pérez RM, Sierra-Santoyo A, Villa-Treviño S. Cancer Prevention Mediated by Caffeic Acid Phenethyl Ester Involves Cyp2b1/2 Modulation in Hepatocarcinogenesis. Toxicol Pathol 2012; 40:466-72. [DOI: 10.1177/0192623311431947] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Affiliation(s)
- Olga Beltrán-Ramírez
- Dirección de Investigación, Hospital Juárez de México, México City, Distrito Federal, México
| | - Roberto Macías Pérez
- Departamento de Biología Celular, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional (CINVESTAV), San Pedro Zacatenco, México
| | - Adolfo Sierra-Santoyo
- Departamento de Toxicología, Centro de Investigación y de Estudios Avanzados del IPN (CINVESTAV). San Pedro Zacatenco, México
| | - Saúl Villa-Treviño
- Departamento de Biología Celular, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional (CINVESTAV), San Pedro Zacatenco, México
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15
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Khokhar JY, Tyndale RF. Rat Brain CYP2B-Enzymatic Activation of Chlorpyrifos to the Oxon Mediates Cholinergic Neurotoxicity. Toxicol Sci 2012; 126:325-35. [DOI: 10.1093/toxsci/kfs029] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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16
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Khokhar JY, Tyndale RF. Drug metabolism within the brain changes drug response: selective manipulation of brain CYP2B alters propofol effects. Neuropsychopharmacology 2011; 36:692-700. [PMID: 21107310 PMCID: PMC3055692 DOI: 10.1038/npp.2010.202] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Drug-metabolizing cytochrome P450 (CYPs) enzymes are expressed in the liver, as well as in extrahepatic tissues such as the brain. Here we show for the first time that drug metabolism by a CYP within the brain, illustrated using CYP2B and the anesthetic propofol (2, 6-diisopropylphenol, Diprivan), can meaningfully alter the pharmacological response to a CNS acting drug. CYP2B is expressed in the brains of animals and humans, and this CYP isoform is able to metabolize centrally acting substrates such as propofol, ecstasy, and serotonin. Rats were given intracerebroventricularly (i.c.v.) injections of vehicle, C8-xanthate, or 8-methoxypsoralen (CYP2B mechanism-based inhibitors) and then tested for sleep time following propofol (80 mg/kg intraperitoneally). Both inhibitors significantly increased sleep-time (1.8- to 2-fold) and brain propofol levels, while having no effect on plasma propofol levels. Seven days of nicotine treatment can induce the expression of brain, but not hepatic, CYP2B, and this induction reduced propofol sleep times by 2.5-fold. This reduction was reversed in a dose-dependent manner by i.c.v. injections of inhibitor. Sleep times correlated with brain (r=0.76, P=0.0009), but not plasma (r=0.24, P=0.39) propofol concentrations. Inhibitor treatments increased brain, but not plasma, propofol levels, and had no effect on hepatic enzyme activity. These data indicate that brain CYP2B can metabolize neuroactive substrates (eg, propofol) and can alter their pharmacological response. This has wider implications for localized CYP-mediated metabolism of drugs, neurotransmitters, and neurotoxins within the brain by this highly variable enzyme family and other CYP subfamilies expressed in the brain.
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Affiliation(s)
- Jibran Y Khokhar
- Centre for Addiction and Mental Health (CAMH) and Departments of Pharmacology and Toxicology and Psychiatry, University of Toronto, Toronto, Ontario, Canada
| | - Rachel F Tyndale
- Centre for Addiction and Mental Health (CAMH) and Departments of Pharmacology and Toxicology and Psychiatry, University of Toronto, Toronto, Ontario, Canada,Department of Pharmacology and Toxicology, 1 King's College Circle, University of Toronto, Medical Sciences Building, Room 4326, Toronto, Ontario M5S 1A8, Canada, Tel: +1 416 978 6374, Fax: +1 416 978 6395, E-mail:
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