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Nkoy FL, Stone BL, Deering-Rice CE, Zhu A, Lamb JG, Rower JE, Reilly CA. Impact of CYP3A5 Polymorphisms on Pediatric Asthma Outcomes. Int J Mol Sci 2024; 25:6548. [PMID: 38928254 PMCID: PMC11203737 DOI: 10.3390/ijms25126548] [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: 04/17/2024] [Revised: 06/03/2024] [Accepted: 06/11/2024] [Indexed: 06/28/2024] Open
Abstract
Genetic variation among inhaled corticosteroid (ICS)-metabolizing enzymes may affect asthma control, but evidence is limited. This study tested the hypothesis that single-nucleotide polymorphisms (SNPs) in Cytochrome P450 3A5 (CYP3A5) would affect asthma outcomes. Patients aged 2-18 years with persistent asthma were recruited to use the electronic AsthmaTracker (e-AT), a self-monitoring tool that records weekly asthma control, medication use, and asthma outcomes. A subset of patients provided saliva samples for SNP analysis and participated in a pharmacokinetic study. Multivariable regression analysis adjusted for age, sex, race, and ethnicity was used to evaluate the impact of CYP3A5 SNPs on asthma outcomes, including asthma control (measured using the asthma symptom tracker, a modified version of the asthma control test or ACT), exacerbations, and hospital admissions. Plasma corticosteroid and cortisol concentrations post-ICS dosing were also assayed using liquid chromatography-tandem mass spectrometry. Of the 751 patients using the e-AT, 166 (22.1%) provided saliva samples and 16 completed the PK study. The e-AT cohort was 65.1% male, and 89.6% White, 6.0% Native Hawaiian, 1.2% Black, 1.2% Native American, 1.8% of unknown race, and 15.7% Hispanic/Latino; the median age was 8.35 (IQR: 5.51-11.3) years. CYP3A5*3/*3 frequency was 75.8% in White subjects, 50% in Native Hawaiians and 76.9% in Hispanic/Latino subjects. Compared with CYP3A5*3/*3, the CYP3A5*1/*x genotype was associated with reduced weekly asthma control (OR: 0.98; 95% CI: 0.97-0.98; p < 0.001), increased exacerbations (OR: 6.43; 95% CI: 4.56-9.07; p < 0.001), and increased asthma hospitalizations (OR: 1.66; 95% CI: 1.43-1.93; p < 0.001); analysis of 3/*3, *1/*1 and *1/*3 separately showed an allelic copy effect. Finally, PK analysis post-ICS dosing suggested muted changes in cortisol concentrations for patients with the CYP3A5*3/*3 genotype, as opposed to an effect on ICS PK. Detection of CYP3A5*3/3, CYPA35*1/*3, and CYP3A5*1/*1 could impact inhaled steroid treatment strategies for asthma in the future.
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Affiliation(s)
- Flory L. Nkoy
- Department of Pediatrics, University of Utah School of Medicine, 100 N. Mario Capecchi Drive, Salt Lake City, UT 84113, USA; (F.L.N.); (B.L.S.); (A.Z.)
| | - Bryan L. Stone
- Department of Pediatrics, University of Utah School of Medicine, 100 N. Mario Capecchi Drive, Salt Lake City, UT 84113, USA; (F.L.N.); (B.L.S.); (A.Z.)
| | - Cassandra E. Deering-Rice
- Department of Pharmacology and Toxicology, Center for Human Toxicology, University of Utah, 30 S 2000 E, Room 201 Skaggs Hall, Salt Lake City, UT 84112, USA; (C.E.D.-R.); (J.G.L.); (J.E.R.)
| | - Angela Zhu
- Department of Pediatrics, University of Utah School of Medicine, 100 N. Mario Capecchi Drive, Salt Lake City, UT 84113, USA; (F.L.N.); (B.L.S.); (A.Z.)
| | - John G. Lamb
- Department of Pharmacology and Toxicology, Center for Human Toxicology, University of Utah, 30 S 2000 E, Room 201 Skaggs Hall, Salt Lake City, UT 84112, USA; (C.E.D.-R.); (J.G.L.); (J.E.R.)
| | - Joseph E. Rower
- Department of Pharmacology and Toxicology, Center for Human Toxicology, University of Utah, 30 S 2000 E, Room 201 Skaggs Hall, Salt Lake City, UT 84112, USA; (C.E.D.-R.); (J.G.L.); (J.E.R.)
| | - Christopher A. Reilly
- Department of Pharmacology and Toxicology, Center for Human Toxicology, University of Utah, 30 S 2000 E, Room 201 Skaggs Hall, Salt Lake City, UT 84112, USA; (C.E.D.-R.); (J.G.L.); (J.E.R.)
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2
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Wang G, Xiao B, Deng J, Gong L, Li Y, Li J, Zhong Y. The Role of Cytochrome P450 Enzymes in COVID-19 Pathogenesis and Therapy. Front Pharmacol 2022; 13:791922. [PMID: 35185562 PMCID: PMC8847594 DOI: 10.3389/fphar.2022.791922] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2021] [Accepted: 01/05/2022] [Indexed: 12/15/2022] Open
Abstract
Coronavirus disease 2019 (COVID-19) has become a new public health crisis threatening the world. Dysregulated immune responses are the most striking pathophysiological features of patients with severe COVID-19, which can result in multiple-organ failure and death. The cytochrome P450 (CYP) system is the most important drug metabolizing enzyme family, which plays a significant role in the metabolism of endogenous or exogenous substances. Endogenous CYPs participate in the biosynthesis or catabolism of endogenous substances, including steroids, vitamins, eicosanoids, and fatty acids, whilst xenobiotic CYPs are associated with the metabolism of environmental toxins, drugs, and carcinogens. CYP expression and activity are greatly affected by immune response. However, changes in CYP expression and/or function in COVID-19 and their impact on COVID-19 pathophysiology and the metabolism of therapeutic agents in COVID-19, remain unclear. In this analysis, we review current evidence predominantly in the following areas: firstly, the possible changes in CYP expression and/or function in COVID-19; secondly, the effects of CYPs on the metabolism of arachidonic acid, vitamins, and steroid hormones in COVID-19; and thirdly, the effects of CYPs on the metabolism of therapeutic COVID-19 drugs.
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Affiliation(s)
- Guyi Wang
- Department of Critical Care Medicine, The Second Xiangya Hospital, Central South University, Changsha, China
| | - Bing Xiao
- Department of Emergency, The Second Xiangya Hospital, Central South University, Changsha, China
| | - Jiayi Deng
- Department of Critical Care Medicine, The Second Xiangya Hospital, Central South University, Changsha, China
| | - Linmei Gong
- Department of Critical Care Medicine, The Second Xiangya Hospital, Central South University, Changsha, China
| | - Yi Li
- Department of Cardiology, The Second Xiangya Hospital, Central South University, Changsha, China
| | - Jinxiu Li
- Department of Critical Care Medicine, The Second Xiangya Hospital, Central South University, Changsha, China
| | - Yanjun Zhong
- Department of Critical Care Medicine, The Second Xiangya Hospital, Central South University, Changsha, China
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3
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Skauby RH, Bergan S, Andersen AM, Vethe NT, Christensen H. In vitro assessments predict that CYP3A4 contributes to a greater extent than CYP3A5 to prednisolone clearance. Basic Clin Pharmacol Toxicol 2021; 129:427-436. [PMID: 34396687 DOI: 10.1111/bcpt.13645] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2021] [Revised: 07/15/2021] [Accepted: 08/11/2021] [Indexed: 11/28/2022]
Abstract
Because several steroid hormones are metabolized to their respective 6β-hydroxy forms by CYP3A4 and CYP3A5, these isoenzymes have been assumed to metabolize the immunosuppressive drug prednisolone, with conflicting results in the literature with respect to their relative importance. A direct study of the metabolism of prednisolone by microsomal CYP3A4 and CYP3A5 is missing. The aim of this in vitro study was to investigate the relative importance of recombinant CYP3A4 and recombinant CYP3A5 in the metabolism of prednisolone and to compare the extent of formation of 6β-OH-prednisolone by the two enzymes. Through in vitro incubations using rCYP3A4 and rCYP3A5 enzymes, intrinsic clearance (CLint ) of prednisolone was determined by the substrate depletion approach. Formation of the metabolite 6β-OH-prednisolone by rCYP3A4 and rCYP3A5, respectively, were compared. Prednisolone concentrations were measured and its metabolite 6β-OH-prednisolone was identified using a HPLC-MS/MS in-house method. CLint for prednisolone by rCYP3A5 was less than 26% relative to rCYP3A4. Formation of 6β -OH-prednisolone by rCYP3A5 was less than 11% relative to rCYP3A4. The study indicates that 6β-hydroxylation of prednisolone assessed in vitro in recombinant CYP enzymes depends on rCYP3A4 rather than rCYP3A5, and that CYP3A5 may be responsible for the formation of other prednisolone metabolite(s) in addition to 6β-OH-prednisolone.
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Affiliation(s)
- Ragnhild Heier Skauby
- Department of Pharmacology, Oslo University Hospital, Norway.,Department of Medical Biochemistry, Oslo University Hospital, Norway.,Faculty of Medicine, Institute of Clinical Medicine, University of Oslo, Norway
| | - Stein Bergan
- Department of Pharmacology, Oslo University Hospital, Norway.,Section for Pharmacology and Pharmaceutical Biosciences, Department of Pharmacy, University of Oslo, Norway
| | | | - Nils Tore Vethe
- Department of Pharmacology, Oslo University Hospital, Norway
| | - Hege Christensen
- Section for Pharmacology and Pharmaceutical Biosciences, Department of Pharmacy, University of Oslo, Norway
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4
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Enlo-Scott Z, Bäckström E, Mudway I, Forbes B. Drug metabolism in the lungs: opportunities for optimising inhaled medicines. Expert Opin Drug Metab Toxicol 2021; 17:611-625. [DOI: 10.1080/17425255.2021.1908262] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Affiliation(s)
- Zachary Enlo-Scott
- Institute of Pharmaceutical Science, Faculty of Life Sciences and Medicine, King’s College London, London, UK
| | - Erica Bäckström
- Drug Metabolism and Pharmacokinetics, Research and Early Development, Respiratory and Immunology (R&I), BioPharmaceuticals R&D, AstraZeneca, Gothenburg, Sweden
| | - Ian Mudway
- MRC Centre for Environment and Health, School of Population Health & Environmental Sciences, Imperial College London, London, United Kingdom; National Institute for Health Research, Health Protection Research Units in Chemical and Radiation Threats and Hazards and Environmental Exposures and Health, Imperial College London, London, UK
| | - Ben Forbes
- Institute of Pharmaceutical Science, Faculty of Life Sciences and Medicine, King’s College London, London, UK
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Brovkina AF, Sychev DA, Toropova OS. [Influence of CYP3A4, CYP3A5, and NR3C1 genes polymorphism on the effectiveness of glucocorticoid therapy in patients with endocrine ophthalmopathy]. Vestn Oftalmol 2020; 136:125-132. [PMID: 33371640 DOI: 10.17116/oftalma2020136062125] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
For more than 60 years, glucocorticoid therapy has been practically the only method for treating patients with endocrine ophthalmopathy - non-specific autoimmune inflammation of the soft tissues of the orbit. Steroid-resistant forms of this disease are known to exist. The reasons for the formation of glucocorticoid resistance are not fully understood yet. PURPOSE To study the possibilities of pharmacogenetic testing for the polymorphism of the glucocorticoid receptor gene NR3C1 and cytochrome P450 in predicting the effectiveness of glucocorticoid therapy in patients with edematous exophthalmos - one of the clinical forms of endocrine ophthalmopathy. MATERIAL AND METHODS The results of glucocorticoid therapy were analyzed in 75 patients with different clinical forms of endocrine ophthalmopathy aged 27 to 84 years. All patients underwent standard ophthalmological examination, external examination of the eye with assessment of the state of periorbital tissues, determination of the shape and size of the palpebral fissure (vertical size), position of the eye in orbit, Hertel exophthalmometry, ultrasound scanning and computed tomography of the orbits. Genetic analysis of the polymorphism of the studied genes was carried out using real-time polymerase chain reaction (real-time PCR). RESULTS The study did not find patterns in the distribution of homo- and heterozygous genotypes of A6986G polymorphic markers of the CYP3A5 gene, 6 C>T intron of the CYP3A4 gene and rs6190 of the NR3C1 gene in patients with endocrine ophthalmopathy and their effect on the glucocorticoid response (p>0.05). CONCLUSION Results of pharmacogenetic testing of the gene for the glucocorticoid receptor NR3C1 and cytochrome P450 do not provide a reliable confirmation of the influence of the polymorphism of the studied genes on the effectiveness of glucocorticoid therapy in patients with endocrine ophthalmopathy.
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Affiliation(s)
- A F Brovkina
- Russian Medical Academy of Continuous Professional Education, Moscow, Russia
| | - D A Sychev
- Russian Medical Academy of Continuous Professional Education, Moscow, Russia
| | - O S Toropova
- Russian Medical Academy of Continuous Professional Education, Moscow, Russia
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Papi A, Mansur AH, Pertseva T, Kaiser K, McIver T, Grothe B, Dissanayake S. Long-Term Fluticasone Propionate/Formoterol Fumarate Combination Therapy Is Associated with a Low Incidence of Severe Asthma Exacerbations. J Aerosol Med Pulm Drug Deliv 2016; 29:346-61. [PMID: 27104231 PMCID: PMC4965704 DOI: 10.1089/jamp.2015.1255] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2015] [Accepted: 01/21/2016] [Indexed: 01/14/2023] Open
Abstract
BACKGROUND A primary goal of asthma management is the reduction of exacerbation risk. We assessed the occurrence of oral corticosteroid-requiring exacerbations (OCS exacerbations) with long-term fluticasone/formoterol therapy, and compared it with the occurrence of similar events reported with other inhaled corticosteroid/long acting β2-agonist (ICS/LABA) combinations. METHODS The occurrence of OCS exacerbations was assessed in two open-label trials of fixed-dose fluticasone/formoterol administered for between 26 to 60 weeks in adults and adolescents with asthma. The incidence of OCS exacerbations with fluticasone/formoterol was compared with those reported in three recent Cochrane meta-analyses of other ICS/LABAs. RESULTS The pooled incidence of OCS exacerbations with long-term fluticasone/formoterol was 2.1% (95% CI: 1.1, 3.2%, n/N = 16/752). In only two of the nineteen treatment arms summarized by Cochrane did OCS exacerbation incidence approximate that seen in the two fluticasone/formoterol trials (single-inhaler fluticasone/salmeterol [2.9%]; separate inhaler budesonide, beclometasone, or flunisolide plus formoterol [3.4%]). In Lasserson's review the pooled incidence of OCS exacerbations for single-inhaler combinations was 9.5% (95% CI: 8.4, 10.6%; n/N = 239/2516) for fluticasone/salmeterol, and 10.6% (95% CI: 9.3, 11.8%; n/N = 257/2433) for budesonide/formoterol. In Ducharme's and Chauhan's meta-analyses (primarily incorporating separate inhaler combinations [fluticasone, budesonide, beclometasone, or flunisolide plus salmeterol or formoterol]), the pooled incidences of OCS exacerbations were 16.0% (95% CI: 14.2, 17.8%, n/N = 258/1615) and 16.7% (95% CI: 14.9, 18.5, n/N = 275/1643), respectively. CONCLUSIONS The incidence of exacerbations in two fixed-dose fluticasone/formoterol studies was low and less than in the majority of comparable published studies involving other ICS/LABA combinations. This difference could not be readily explained by differences in features of the respective studies and may be related to the favorable pharmacological/mechanistic characteristics of the constituent components fluticasone and formoterol compared to other drugs in their respective classes.
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Affiliation(s)
- Alberto Papi
- Research Centre on Asthma and COPD, University of Ferrara, Ferrara, Italy
| | - Adel H. Mansur
- Chest Research Institute, Birmingham Heartlands Hospital, Birmingham, United Kingdom
| | | | - Kirsten Kaiser
- Medicinal and Regulatory Development, Skyepharma AG, Muttenz, Switzerland
| | - Tammy McIver
- Clinical Data Management and Statistics, Mundipharma Research Limited, Cambridge, United Kingdom
| | - Birgit Grothe
- Medical Science—Respiratory, Mundipharma Research Limited, Cambridge, United Kingdom
| | - Sanjeeva Dissanayake
- Medical Science—Respiratory, Mundipharma Research Limited, Cambridge, United Kingdom
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7
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CYP3A5 mediates bioactivation and cytotoxicity of tetrandrine. Arch Toxicol 2015; 90:1737-48. [DOI: 10.1007/s00204-015-1584-8] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2015] [Accepted: 08/13/2015] [Indexed: 10/23/2022]
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8
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Stockmann C, Fassl B, Gaedigk R, Nkoy F, Uchida DA, Monson S, Reilly CA, Leeder JS, Yost GS, Ward RM. Fluticasone propionate pharmacogenetics: CYP3A4*22 polymorphism and pediatric asthma control. J Pediatr 2013; 162:1222-7, 1227.e1-2. [PMID: 23290512 PMCID: PMC3620714 DOI: 10.1016/j.jpeds.2012.11.031] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/11/2012] [Revised: 10/10/2012] [Accepted: 11/13/2012] [Indexed: 10/27/2022]
Abstract
OBJECTIVE To determine the relationship between allelic variations in genes involved in fluticasone propionate (FP) metabolism and asthma control among children with asthma managed with inhaled FP. STUDY DESIGN The relationship between variability in asthma control scores and genetic variation in drug metabolism was assessed by genotyping 9 single nucleotide polymorphisms in the CYP3A4, CYP3A5, and CYP3A7 genes. Genotype information was compared with asthma control scores (0=well controlled to 15=poorly controlled), determined using a questionnaire modified from the National Heart Lung and Blood Institute's Expert Panel 3 guidelines. RESULTS Our study cohort comprised 734 children with asthma (mean age, 8.8±4.3 years) and was predominantly male (61%) and non-Hispanic white (53%). More than one-half of the children (56%; n=413) were receiving an inhaled glucocorticoid daily, with FP the most frequently prescribed agent (65%). Among the children receiving daily FP, single nucleotide polymorphisms in CYP3A5 and CYP3A7 were not associated with asthma control scores. In contrast, asthma control scores were significantly improved in the 20 children (7%) with the CYP3A4*22 allele (median, 3; range, 0-6) compared with the 201 children without the CYP3A4*22 allele (median, 4; range, 0-15; P=.02). The presence of CYP3A4*22 was associated with improved asthma control scores by 2.1 points (95% CI, 0.5-3.8). CONCLUSION The presence of CYP3A4*22, which is associated with decreased hepatic CYP3A4 expression and activity, was accompanied by improved asthma control in the FP-treated children. Decreased CYP3A4 activity may improve asthma control with inhaled FP.
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Affiliation(s)
- Chris Stockmann
- Department of Pediatrics, University of Utah School of Medicine
,Department of Pharmacology/Toxicology, University of Utah College of Pharmacy
| | - Bernhard Fassl
- Department of Pediatrics, University of Utah School of Medicine
| | - Roger Gaedigk
- Developmental Pharmacology and Experimental Therapeutics Laboratory, University of Missouri Kansas City
| | - Flory Nkoy
- Department of Pediatrics, University of Utah School of Medicine
| | - Derek A. Uchida
- Department of Pediatrics, University of Utah School of Medicine
| | - Steven Monson
- Department of Pediatrics, University of Utah School of Medicine
| | | | - J. Steven Leeder
- Developmental Pharmacology and Experimental Therapeutics Laboratory, University of Missouri Kansas City
| | - Garold S. Yost
- Department of Pharmacology/Toxicology, University of Utah College of Pharmacy
| | - Robert M. Ward
- Department of Pediatrics, University of Utah School of Medicine
,Department of Pharmacology/Toxicology, University of Utah College of Pharmacy
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9
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Roberts JK, Moore CD, Ward RM, Yost GS, Reilly CA. Metabolism of beclomethasone dipropionate by cytochrome P450 3A enzymes. J Pharmacol Exp Ther 2013; 345:308-16. [PMID: 23512537 DOI: 10.1124/jpet.112.202556] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Inhaled glucocorticoids, such as beclomethasone dipropionate (BDP), are the mainstay treatment of asthma. However, ≈ 30% of patients exhibit little to no benefit from treatment. It has been postulated that glucocorticoid resistance, or insensitivity, is attributable to individual differences in glucocorticoid receptor-mediated processes. It is possible that variations in cytochrome P450 3A enzyme-mediated metabolism of BDP may contribute to this phenomenon. This hypothesis was explored by evaluating the contributions of CYP3A4, 3A5, 3A7, and esterase enzymes in the metabolism of BDP in vitro and relating metabolism to changes in CYP3A enzyme mRNA expression via the glucocorticoid receptor in lung and liver cells. CYP3A4 and CYP3A5 metabolized BDP via hydroxylation ([M4] and [M6]) and dehydrogenation ([M5]) at similar rates; CYP3A7 did not metabolize BDP. A new metabolite [M6], formed by the combined action of esterases and CYP3A4 hydroxylation, was also characterized. To validate the results observed using microsomes and recombinant enzymes, studies were also conducted using A549 lung and DPX2 liver cells. Both liver and lung cells produced esterase-dependent metabolites [M1-M3], with [M1] correlating with CYP3A5 mRNA induction in A549 cells. Liver cells produced both hydroxylated and dehydrogenated metabolites [M4, M5, and M6], but lung cells produced only the dehydrogenated metabolite [M5]. These studies show that CYP3A4 and CYP3A5 metabolize BDP to inactive metabolites and suggest that differences in the expression or function of these enzymes in the lung and/or liver could influence BDP disposition in humans.
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Affiliation(s)
- Jessica K Roberts
- Department of Pharmacology and Toxicology, College of Pharmacy, University of Utah, Salt Lake City, Utah, USA
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10
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Moore CD, Roberts JK, Orton CR, Murai T, Fidler TP, Reilly CA, Ward RM, Yost GS. Metabolic pathways of inhaled glucocorticoids by the CYP3A enzymes. Drug Metab Dispos 2012; 41:379-89. [PMID: 23143891 DOI: 10.1124/dmd.112.046318] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Asthma is one of the most prevalent diseases in the world, for which the mainstay treatment has been inhaled glucocorticoids (GCs). Despite the widespread use of these drugs, approximately 30% of asthma sufferers exhibit some degree of steroid insensitivity or are refractory to inhaled GCs. One hypothesis to explain this phenomenon is interpatient variability in the clearance of these compounds. The objective of this research is to determine how metabolism of GCs by the CYP3A family of enzymes could affect their effectiveness in asthmatic patients. In this work, the metabolism of four frequently prescribed inhaled GCs, triamcinolone acetonide, flunisolide, budesonide, and fluticasone propionate, by the CYP3A family of enzymes was studied to identify differences in their rates of clearance and to identify their metabolites. Both interenzyme and interdrug variability in rates of metabolism and metabolic fate were observed. CYP3A4 was the most efficient metabolic catalyst for all the compounds, and CYP3A7 had the slowest rates. CYP3A5, which is particularly relevant to GC metabolism in the lungs, was also shown to efficiently metabolize triamcinolone acetonide, budesonide, and fluticasone propionate. In contrast, flunisolide was only metabolized via CYP3A4, with no significant turnover by CYP3A5 or CYP3A7. Common metabolites included 6β-hydroxylation and Δ(6)-dehydrogenation for triamcinolone acetonide, budesonide, and flunisolide. The structure of Δ(6)-flunisolide was unambiguously established by NMR analysis. Metabolism also occurred on the D-ring substituents, including the 21-carboxy metabolites for triamcinolone acetonide and flunisolide. The novel metabolite 21-nortriamcinolone acetonide was also identified by liquid chromatography-mass spectrometry and NMR analysis.
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Affiliation(s)
- Chad D Moore
- Department of Pharmacology and Toxicology, University of Utah, Salt Lake City, UT 84112, USA
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11
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Tydén E, Löfgren M, Hakhverdyan M, Tjälve H, Larsson P. The genes of all seven CYP3A isoenzymes identified in the equine genome are expressed in the airways of horses. J Vet Pharmacol Ther 2012; 36:370-5. [PMID: 22966936 DOI: 10.1111/jvp.12012] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2012] [Accepted: 08/14/2012] [Indexed: 01/07/2023]
Abstract
In the present study, we examined the gene expression of cytochrome P450 3A (CYP3A) isoenzymes in the tracheal and bronchial mucosa and in the lung of equines using TaqMan probes. The results show that all seven CYP3A isoforms identified in the equine genome, that is, CYP3A89, CYP3A93, CYP3A94, CYP3A95, CYP3A96, CYP3A97 and CYP3A129, are expressed in the airways of the investigated horses. Though in previous studies, CYP3A129 was found to be absent in equine intestinal mucosa and liver, this CYP3A isoform is expressed in the airways of horses. The gene expression of the CYP3A isoenzymes varied considerably between the individual horses studied. However, in most of the horses CYP3A89, CYP3A93, CYP3A96, CYP3A97 and CYP3A129 were expressed to a high extent, while CYP3A94 and CYP3A95 were expressed to a low extent in the different parts of the airways. The CYP3A isoenzymes present in the airways may play a role in the metabolic degradation of inhaled xenobiotics. In some instances, the metabolism may, however, result in bioactivation of the xenobiotics and subsequent tissue injury.
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Affiliation(s)
- E Tydén
- Division of Pathology, Pharmacology and Toxicology, Department of Biomedical Sciences and Veterinary Public Health, Swedish University of Agricultural Sciences, Uppsala, Sweden.
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12
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Stepan AF, Walker DP, Bauman J, Price DA, Baillie TA, Kalgutkar AS, Aleo MD. Structural alert/reactive metabolite concept as applied in medicinal chemistry to mitigate the risk of idiosyncratic drug toxicity: a perspective based on the critical examination of trends in the top 200 drugs marketed in the United States. Chem Res Toxicol 2011; 24:1345-410. [PMID: 21702456 DOI: 10.1021/tx200168d] [Citation(s) in RCA: 492] [Impact Index Per Article: 37.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Because of a preconceived notion that eliminating reactive metabolite (RM) formation with new drug candidates could mitigate the risk of idiosyncratic drug toxicity, the potential for RM formation is routinely examined as part of lead optimization efforts in drug discovery. Likewise, avoidance of "structural alerts" is almost a norm in drug design. However, there is a growing concern that the perceived safety hazards associated with structural alerts and/or RM screening tools as standalone predictors of toxicity risks may be over exaggerated. In addition, the multifactorial nature of idiosyncratic toxicity is now well recognized based upon observations that mechanisms other than RM formation (e.g., mitochondrial toxicity and inhibition of bile salt export pump (BSEP)) also can account for certain target organ toxicities. Hence, fundamental questions arise such as: When is a molecule that contains a structural alert (RM positive or negative) a cause for concern? Could the molecule in its parent form exert toxicity? Can a low dose drug candidate truly mitigate metabolism-dependent and -independent idiosyncratic toxicity risks? In an effort to address these questions, we have retrospectively examined 68 drugs (recalled or associated with a black box warning due to idiosyncratic toxicity) and the top 200 drugs (prescription and sales) in the United States in 2009 for trends in physiochemical characteristics, daily doses, presence of structural alerts, evidence for RM formation as well as toxicity mechanism(s) potentially mediated by parent drugs. Collectively, our analysis revealed that a significant proportion (∼78-86%) of drugs associated with toxicity contained structural alerts and evidence indicating that RM formation as a causative factor for toxicity has been presented in 62-69% of these molecules. In several cases, mitochondrial toxicity and BSEP inhibition mediated by parent drugs were also noted as potential causative factors. Most drugs were administered at daily doses exceeding several hundred milligrams. There was no obvious link between idiosyncratic toxicity and physicochemical properties such as molecular weight, lipophilicity, etc. Approximately half of the top 200 drugs for 2009 (prescription and sales) also contained one or more alerts in their chemical architecture, and many were found to be RM-positive. Several instances of BSEP and mitochondrial liabilities were also noted with agents in the top 200 category. However, with relatively few exceptions, the vast majority of these drugs are rarely associated with idiosyncratic toxicity, despite years of patient use. The major differentiating factor appeared to be the daily dose; most of the drugs in the top 200 list are administered at low daily doses. In addition, competing detoxication pathways and/or alternate nonmetabolic clearance routes provided suitable justifications for the safety records of RM-positive drugs in the top 200 category. Thus, while RM elimination may be a useful and pragmatic starting point in mitigating idiosyncratic toxicity risks, our analysis suggests a need for a more integrated screening paradigm for chemical hazard identification in drug discovery. Thus, in addition to a detailed assessment of RM formation potential (in relationship to the overall elimination mechanisms of the compound(s)) for lead compounds, effects on cellular health (e.g., cytotoxicity assays), BSEP inhibition, and mitochondrial toxicity are the recommended suite of assays to characterize compound liabilities. However, the prospective use of such data in compound selection will require further validation of the cellular assays using marketed agents. Until we gain a better understanding of the pathophysiological mechanisms associated with idiosyncratic toxicities, improving pharmacokinetics and intrinsic potency as means of decreasing the dose size and the associated "body burden" of the parent drug and its metabolites will remain an overarching goal in drug discovery.
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Affiliation(s)
- Antonia F Stepan
- Worldwide Medicinal Chemistry, Pfizer Worldwide Research and Development, Groton, Connecticut 06340, USA
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