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Hammid A, Fallon JK, Vellonen KS, Lassila T, Reinisalo M, Urtti A, Gonzalez F, Tolonen A, Smith PC, Honkakoski P. Aldehyde oxidase 1 activity and protein expression in human, rabbit, and pig ocular tissues. Eur J Pharm Sci 2023; 191:106603. [PMID: 37827455 DOI: 10.1016/j.ejps.2023.106603] [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: 06/07/2023] [Revised: 09/18/2023] [Accepted: 10/06/2023] [Indexed: 10/14/2023]
Abstract
Aldehyde oxidase (AOX) is a cytosolic drug-metabolizing enzyme which has attracted increasing attention in drug development due to its high hepatic expression, broad substrate profile and species differences. In contrast, there is limited information on the presence and activity of AOX in extrahepatic tissues including ocular tissues. Because several ocular drugs are potential substrates for AOX, we performed a comprehensive analysis of the AOX1 expression and activity profile in seven ocular tissues from humans, rabbits, and pigs. AOX activities were determined using optimized assays for the established human AOX1 probe substrates 4-dimethylamino-cinnamaldehyde (DMAC) and phthalazine. Inhibition studies were undertaken in conjunctival and retinal homogenates using well-established human AOX1 inhibitors menadione and chlorpromazine. AOX1 protein contents were quantitated with targeted proteomics and confirmed by immunoblotting. Overall, DMAC oxidation rates varied over 10-fold between species (human ˃˃ rabbit ˃ pig) and showed 2- to 6-fold differences between tissues from the same species. Menadione seemed a more potent inhibitor of DMAC oxidation across species than chlorpromazine. Human AOX1 protein levels were highest in the conjunctiva, followed by most posterior tissues, whereas anterior tissues showed low levels. The rabbit AOX1 expression was high in the conjunctiva, retinal pigment epithelial (RPE), and choroid while lower in the anterior tissues. Quantification of pig AOX1 was not successful but immunoblotting confirmed the presence of AOX1 in all species. DMAC oxidation rates and AOX1 contents correlated quite well in humans and rabbits. This study provides, for the first time, insights into the ocular expression and activity of AOX1 among multiple species.
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Affiliation(s)
- Anam Hammid
- School of Pharmacy, University of Eastern Finland, Yliopistonranta 1 C, FI-70210 Kuopio, Finland.
| | - John K Fallon
- Division of Pharmacoengineering and Molecular Pharmaceutics, Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Campus Box 7355, Chapel Hill, NC 27599-7355, United States
| | - Kati-Sisko Vellonen
- School of Pharmacy, University of Eastern Finland, Yliopistonranta 1 C, FI-70210 Kuopio, Finland
| | - Toni Lassila
- Admescope Ltd, Typpitie 1, FI-90620 Oulu, Finland
| | - Mika Reinisalo
- School of Pharmacy, University of Eastern Finland, Yliopistonranta 1 C, FI-70210 Kuopio, Finland
| | - Arto Urtti
- School of Pharmacy, University of Eastern Finland, Yliopistonranta 1 C, FI-70210 Kuopio, Finland; Faculty of Pharmacy, University of Helsinki, Viikinkaari 5 E, FI-00790 Helsinki, Finland
| | - Francisco Gonzalez
- Center for Research in Molecular Medicine and Chronic Diseases (CIMUS), University of Santiago de Compostela, 15782 Santiago de Compostela, Spain; Service of Ophthalmology, University Hospital of Santiago de Compostela, and Fundacion Instituto de Investigacion Sanitaria de Santiago de Compostela (FIDIS), 15706 Santiago de Compostela, Spain
| | - Ari Tolonen
- Admescope Ltd, Typpitie 1, FI-90620 Oulu, Finland
| | - Philip C Smith
- Division of Pharmacoengineering and Molecular Pharmaceutics, Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Campus Box 7355, Chapel Hill, NC 27599-7355, United States
| | - Paavo Honkakoski
- School of Pharmacy, University of Eastern Finland, Yliopistonranta 1 C, FI-70210 Kuopio, Finland
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Fashe MM, Miner TA, Fallon JK, Schauer AP, Sykes C, Smith PC, Lee CR. Pregnancy related hormones increase CYP3A mediated buprenorphine metabolism in human hepatocytes: a comparison to CYP3A substrates nifedipine and midazolam. Front Pharmacol 2023; 14:1218703. [PMID: 37475714 PMCID: PMC10354249 DOI: 10.3389/fphar.2023.1218703] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2023] [Accepted: 06/22/2023] [Indexed: 07/22/2023] Open
Abstract
Introduction: Pregnancy increases the clearance of CYP3A4 substrate drugs and pregnancy-related hormones (PRHs) induce hepatic CYP3A4 expression and metabolism. However, it remains unclear to what extent the magnitude of PRH-evoked changes in hepatic CYP3A metabolism varies across multiple substrates. This study quantified the impact of PRHs on CYP3A protein concentrations and buprenorphine metabolism in human hepatocytes, and compared the magnitude of these effects to nifedipine and midazolam metabolism. Methods: Sandwich-cultured human hepatocytes (SCHH) from female donors were exposed to PRHs, administered in combination across a range of physiologically relevant concentrations, for 72 h. Absolute protein concentrations of CYP3A4, CYP3A5, and CYP3A7 in SCHH membrane fractions were quantified by nanoLC-MS/MS, and norbuprenorphine (nor-BUP), dehydro-nifedipine (dehydro-NIF), and 1-hydroxy-midazolam (1-OH-MDZ) formation was evaluated. Results: Compared to control, PRH exposure increased CYP3A4, CYP3A7, and total CYP3A protein concentrations, but not CYP3A5 concentrations, and increased nor-BUP, dehydro-NIF, and 1-OH-MDZ formation in a concentration-dependent manner. The formation of nor-BUP, dehydro-NIF, and 1-OH-MDZ each positively correlated with PRH-mediated changes in total CYP3A protein concentrations. The PRH-evoked increase in nor-BUP formation was evident in all donors; however, the PRH induction of dehydro-NIF and 1-OH-MDZ formation was diminished in a hepatocyte donor with high basal CYP3A5 expression. Discussion: These findings demonstrate that PRHs increase buprenorphine, nifedipine, and midazolam metabolism in SCHH via induction of CYP3A4 and total CYP3A protein concentrations, and the magnitude of these effects vary across hepatocyte donors in a substrate-specific manner. These data provide insight into the contribution of PRH induction of CYP3A4 metabolism to increased buprenorphine clearance during pregnancy.
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Affiliation(s)
- Muluneh M Fashe
- Division of Pharmacotherapy and Experimental Therapeutics, UNC Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
| | - Taryn A Miner
- Division of Pharmacotherapy and Experimental Therapeutics, UNC Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
| | - John K Fallon
- Division of Pharmacoengineering and Molecular Pharmaceutics, UNC Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
| | - Amanda P Schauer
- Division of Pharmacotherapy and Experimental Therapeutics, UNC Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
| | - Craig Sykes
- Division of Pharmacotherapy and Experimental Therapeutics, UNC Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
| | - Philip C Smith
- Division of Pharmacoengineering and Molecular Pharmaceutics, UNC Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
| | - Craig R Lee
- Division of Pharmacotherapy and Experimental Therapeutics, UNC Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
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Lee J, Fallon JK, Smith PC, Jackson KD. Formation of CYP3A-specific metabolites of ibrutinib in vitro is correlated with hepatic CYP3A activity and 4β-hydroxycholesterol/cholesterol ratio. Clin Transl Sci 2023; 16:279-291. [PMID: 36350327 PMCID: PMC9926076 DOI: 10.1111/cts.13448] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2022] [Revised: 10/06/2022] [Accepted: 10/28/2022] [Indexed: 11/10/2022] Open
Abstract
Ibrutinib is an orally administered Bruton's tyrosine kinase inhibitor approved for the treatment of B-cell malignancies, including chronic lymphocytic leukemia. Ibrutinib is metabolized primarily via oxidation by cytochrome P450 (CYP) 3A4/5 to M37 (the primary active metabolite), M34, and M25. The objectives of this study were to assess the relationship between formation of the major CYP3A-specific ibrutinib metabolites in vitro and hepatic CYP3A activity and protein abundance, and to evaluate the utility of the endogenous CYP3A biomarker, plasma 4β-hydroxycholesterol (4β-HC) to cholesterol ratio, to predict ibrutinib metabolite formation in individual cadaveric donors with matching hepatocytes. Ibrutinib (5 μM) was incubated with single-donor human liver microsomes (n = 20) and primary human hepatocytes (n = 15), and metabolites (M37, M34, and M25) were measured by liquid chromatography-tandem mass spectrometry analysis. CYP3A4/5 protein concentrations were measured by quantitative targeted absolute proteomics, and CYP3A activity was measured by midazolam 1'-hydroxylation. Ibrutinib metabolite formation positively correlated with midazolam 1'-hydroxylation in human liver microsomes and hepatocytes. Plasma 4β-HC and cholesterol concentrations were measured in plasma samples obtained at the time of liver harvest from the same 15 donors with matching hepatocytes. Midazolam 1'-hydroxylation in hepatocytes correlated with plasma 4β-HC/cholesterol ratio. When an infant donor (1 year old) was excluded based on previous ontogeny studies, M37 and M25 formation correlated with plasma 4β-HC/cholesterol ratio in the remaining 14 donors (Spearman correlation coefficients [r] 0.62 and 0.67, respectively). Collectively, these data indicate a positive association among formation of CYP3A-specific ibrutinib metabolites in human hepatocytes, hepatic CYP3A activity, and plasma 4β-HC/cholesterol ratio in the same non-infant donors.
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Affiliation(s)
- Jonghwa Lee
- Division of Pharmacotherapy and Experimental TherapeuticsUniversity of North Carolina at Chapel Hill Eshelman School of PharmacyChapel HillNorth CarolinaUSA
| | - John K. Fallon
- Division of Pharmacoengineering and Molecular PharmaceuticsUniversity of North Carolina at Chapel Hill Eshelman School of PharmacyChapel HillNorth CarolinaUSA
| | - Philip C. Smith
- Division of Pharmacoengineering and Molecular PharmaceuticsUniversity of North Carolina at Chapel Hill Eshelman School of PharmacyChapel HillNorth CarolinaUSA
| | - Klarissa D. Jackson
- Division of Pharmacotherapy and Experimental TherapeuticsUniversity of North Carolina at Chapel Hill Eshelman School of PharmacyChapel HillNorth CarolinaUSA
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Fashe MM, Fallon JK, Miner TA, Tiley JB, Smith PC, Lee CR. Impact of pregnancy related hormones on drug metabolizing enzyme and transport protein concentrations in human hepatocytes. Front Pharmacol 2022; 13:1004010. [PMID: 36210832 PMCID: PMC9532936 DOI: 10.3389/fphar.2022.1004010] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2022] [Accepted: 08/22/2022] [Indexed: 11/13/2022] Open
Abstract
Pregnancy alters the disposition and exposure to multiple drugs indicated for pregnancy-related complications. Previous in vitro studies have shown that pregnancy-related hormones (PRHs) alter the expression and function of certain cytochrome P450s (CYPs) in human hepatocytes. However, the impact of PRHs on hepatic concentrations of non-CYP drug-metabolizing enzymes (DMEs) and transport proteins remain largely unknown. In this study, sandwich-cultured human hepatocytes (SCHH) from five female donors were exposed to vehicle or PRHs (estrone, estradiol, estriol, progesterone, cortisol, and placental growth hormone), administered individually or in combination, across a range of physiologically relevant PRH concentrations for 72 h. Absolute concentrations of 33 hepatic non-CYP DMEs and transport proteins were quantified in SCHH membrane fractions using a quantitative targeted absolute proteomics (QTAP) isotope dilution nanoLC-MS/MS method. The data revealed that PRHs altered the absolute protein concentration of various DMEs and transporters in a concentration-, isoform-, and hepatocyte donor-dependent manner. Overall, eight of 33 (24%) proteins exhibited a significant PRH-evoked net change in absolute protein concentration relative to vehicle control (ANOVA p < 0.05) across hepatocyte donors: 1/11 UGTs (9%; UGT1A4), 4/6 other DMEs (67%; CES1, CES2, FMO5, POR), and 3/16 transport proteins (19%; OAT2, OCT3, P-GP). An additional 8 (24%) proteins (UGT1A1, UGT2B4, UGT2B10, FMO3, OCT1, MRP2, MRP3, ENT1) exhibited significant PRH alterations in absolute protein concentration within at least two individual hepatocyte donors. In contrast, 17 (52%) proteins exhibited no discernable impact by PRHs either within or across hepatocyte donors. Collectively, these results provide the first comprehensive quantitative proteomic evaluation of PRH effects on non-CYP DMEs and transport proteins in SCHH and offer mechanistic insight into the altered disposition of drug substrates cleared by these pathways during pregnancy.
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Affiliation(s)
- Muluneh M. Fashe
- Division of Pharmacotherapy and Experimental Therapeutics, UNC Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
| | - John K. Fallon
- Division of Pharmacoengineering and Molecular Pharmaceutics, UNC Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
| | - Taryn A. Miner
- Division of Pharmacotherapy and Experimental Therapeutics, UNC Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
| | - Jacqueline B. Tiley
- Division of Pharmacotherapy and Experimental Therapeutics, UNC Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
| | - Philip C. Smith
- Division of Pharmacoengineering and Molecular Pharmaceutics, UNC Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
| | - Craig R. Lee
- Division of Pharmacotherapy and Experimental Therapeutics, UNC Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
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5
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Morse BL, Fallon JK, Kolur A, Hogan AT, Smith PC, Hillgren KM. Comparison of Hepatic Transporter Tissue Expression in Rodents and Interspecies Hepatic OCT1 Activity. AAPS J 2021; 23:58. [PMID: 33903987 DOI: 10.1208/s12248-021-00583-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2020] [Accepted: 03/16/2021] [Indexed: 11/30/2022] Open
Abstract
Hepatic clearance may be uptake rate limited by organic anion transporting polypeptides (OATPs) and organic cation transporter 1 (OCT1). While comparison of OATP activity has been investigated across species, little has been reported for OCT1. Additionally, while data on interspecies transporter expression in the liver exist, quantitative comparison of these transporters in multiple tissues is lacking. In the current research, the pharmacokinetics of OCT1 substrates (sumatriptan and metformin) were assessed in Oct knockout rats for comparison with previous Oct1/2-/- mice data and OCT1 pharmacogenetics in humans. Effect of OCT1 inhibitors verapamil and erlotinib on OCT1 substrate liver partitioning was also evaluated in rats. Expression of 18 transporters, including Oatps and Octs, in 9 tissues from mice and rats was quantitated using nanoLC/MS-MS, along with uptake transporters in hepatocytes from 5 species. Interspecies differences in OCT1 activity were further evaluated via uptake of OCT1 substrates in hepatocytes with corresponding in vivo liver partitioning in rodents and monkey. In Oct1-/- rats, sumatriptan hepatic clearance and liver partitioning decreased; however, metformin pharmacokinetics were unaffected. OCT1 inhibitor coadministration decreased sumatriptan liver partitioning. In rodents, Oatp expression was highest in the liver, although comparable expression of Oatps in other tissues was determined. Expression of Octs was highest in the kidney, with liver Oct1 expression comparably lower than Oatps. Liver partitioning of OCT1 substrates was lower in rodents than in monkey, in agreement with the highest OCT1 expression and uptake of OCT1 substrates in monkey hepatocytes. Species-dependent OCT1 activity requires consideration when translating preclinical data to the clinic.
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Affiliation(s)
- Bridget L Morse
- Drug Disposition, Eli Lilly and Company, Lilly Corporate Center, Indianapolis, IN, 46285, USA.
| | - John K Fallon
- Division of Pharmacoengineering and Molecular Pharmaceutics, Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Anil Kolur
- Drug Disposition, Eli Lilly and Company, Lilly Corporate Center, Indianapolis, IN, 46285, USA
| | - Andrew T Hogan
- Drug Disposition, Eli Lilly and Company, Lilly Corporate Center, Indianapolis, IN, 46285, USA
| | - Philip C Smith
- Division of Pharmacoengineering and Molecular Pharmaceutics, Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Kathleen M Hillgren
- Drug Disposition, Eli Lilly and Company, Lilly Corporate Center, Indianapolis, IN, 46285, USA
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Khatri R, Fallon JK, Sykes C, Kulick N, Rementer RJB, Miner TA, Schauer AP, Kashuba ADM, Boggess KA, Brouwer KLR, Smith PC, Lee CR. Pregnancy-Related Hormones Increase UGT1A1-Mediated Labetalol Metabolism in Human Hepatocytes. Front Pharmacol 2021; 12:655320. [PMID: 33995076 PMCID: PMC8115026 DOI: 10.3389/fphar.2021.655320] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2021] [Accepted: 03/11/2021] [Indexed: 11/25/2022] Open
Abstract
Pregnancy-related hormones (PRH) are recognized as important regulators of hepatic cytochrome P450 enzyme expression and function. However, the impact of PRH on the hepatic expression and function of uridine diphosphate glucuronosyltransferases (UGTs) remains unclear. Using primary human hepatocytes, we evaluated the effect of PRH exposure on mRNA levels and protein concentrations of UGT1A1, UGT2B7, and other key UGT enzymes, and on the metabolism of labetalol (a UGT1A1 and UGT2B7 substrate commonly prescribed to treat hypertensive disorders of pregnancy). Sandwich-cultured human hepatocytes (SCHH) from female donors were exposed to the PRH estradiol, estriol, estetrol, progesterone, and cortisol individually or in combination. We quantified protein concentrations of UGT1A1, UGT2B7, and four additional UGT1A isoforms in SCHH membrane fractions and evaluated the metabolism of labetalol to its glucuronide metabolites in SCHH. PRH exposure increased mRNA levels and protein concentrations of UGT1A1 and UGT1A4 in SCHH. PRH exposure also significantly increased labetalol metabolism to its UGT1A1-derived glucuronide metabolite in a concentration-dependent manner, which positively correlated with PRH-induced changes in UGT1A1 protein concentrations. In contrast, PRH did not alter UGT2B7 mRNA levels or protein concentrations in SCHH, and formation of the UGT2B7-derived labetalol glucuronide metabolite was decreased following PRH exposure. Our findings demonstrate that PRH alter expression and function of UGT proteins in an isoform-specific manner and increase UGT1A1-mediated labetalol metabolism in human hepatocytes by inducing UGT1A1 protein concentrations. These results provide mechanistic insight into the increases in labetalol clearance observed in pregnant individuals.
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Affiliation(s)
- Raju Khatri
- Division of Pharmacotherapy and Experimental Therapeutics, UNC Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
| | - John K. Fallon
- Division of Pharmacoengineering and Molecular Pharmaceutics, UNC Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
| | - Craig Sykes
- Division of Pharmacotherapy and Experimental Therapeutics, UNC Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
| | - Natasha Kulick
- Division of Pharmacotherapy and Experimental Therapeutics, UNC Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
| | - Rebecca J. B. Rementer
- Division of Pharmacotherapy and Experimental Therapeutics, UNC Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
| | - Taryn A. Miner
- Division of Pharmacotherapy and Experimental Therapeutics, UNC Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
| | - Amanda P. Schauer
- Division of Pharmacotherapy and Experimental Therapeutics, UNC Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
| | - Angela D. M. Kashuba
- Division of Pharmacotherapy and Experimental Therapeutics, UNC Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
| | - Kim A. Boggess
- Department of Obstetrics and Gynecology, UNC School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
| | - Kim L. R. Brouwer
- Division of Pharmacotherapy and Experimental Therapeutics, UNC Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
| | - Philip C. Smith
- Division of Pharmacoengineering and Molecular Pharmaceutics, UNC Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
| | - Craig R. Lee
- Division of Pharmacotherapy and Experimental Therapeutics, UNC Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
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Hammid A, Fallon JK, Lassila T, Salluce G, Smith PC, Tolonen A, Sauer A, Urtti A, Honkakoski P. Carboxylesterase Activities and Protein Expression in Rabbit and Pig Ocular Tissues. Mol Pharm 2021; 18:1305-1316. [PMID: 33595329 PMCID: PMC8023712 DOI: 10.1021/acs.molpharmaceut.0c01154] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2020] [Revised: 02/08/2021] [Accepted: 02/08/2021] [Indexed: 12/12/2022]
Abstract
Hydrolytic reactions constitute an important pathway of drug metabolism and a significant route of prodrug activation. Many ophthalmic drugs and prodrugs contain ester groups that greatly enhance their permeation across several hydrophobic barriers in the eye before the drugs are either metabolized or released, respectively, via hydrolysis. Thus, the development of ophthalmic drug therapy requires the thorough profiling of substrate specificities, activities, and expression levels of ocular esterases. However, such information is scant in the literature, especially for preclinical species often used in ophthalmology such as rabbits and pigs. Therefore, our aim was to generate systematic information on the activity and expression of carboxylesterases (CESs) and arylacetamide deacetylase (AADAC) in seven ocular tissue homogenates from these two species. The hydrolytic activities were measured using a generic esterase substrate (4-nitrophenyl acetate) and, in the absence of validated substrates for rabbit and pig enzymes, with selective substrates established for human CES1, CES2, and AADAC (d-luciferin methyl ester, fluorescein diacetate, procaine, and phenacetin). Kinetics and inhibition studies were conducted using these substrates and, again due to a lack of validated rabbit and pig CES inhibitors, with known inhibitors for the human enzymes. Protein expression levels were measured using quantitative targeted proteomics. Rabbit ocular tissues showed significant variability in the expression of CES1 (higher in cornea, lower in conjunctiva) and CES2 (higher in conjunctiva, lower in cornea) and a poor correlation of CES expression with hydrolytic activities. In contrast, pig tissues appear to express only CES1, and CES3 and AADAC seem to be either low or absent, respectively, in both species. The current study revealed remarkable species and tissue differences in ocular hydrolytic enzymes that can be taken into account in the design of esterase-dependent prodrugs and drug conjugates, the evaluation of ocular effects of systemic drugs, and in translational and toxicity studies.
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Affiliation(s)
- Anam Hammid
- School
of Pharmacy, University of Eastern Finland, Yliopistonranta 1 C, 70210 Kuopio, Finland
| | - John K. Fallon
- Division
of Pharmacoengineering and Molecular Pharmaceutics, Eshelman School
of Pharmacy, University of North Carolina
at Chapel Hill, Campus Box 7355, Chapel Hill, North Carolina 27599-7355, United States
| | | | - Giulia Salluce
- Centro
Singular de Investigación en Química Biolóxica
e Materiais Moleculares (CiQUS), Departamento de Química Orgánica, Universidade de Santiago de Compostela, 15782 Santiago
de Compostela, Spain
| | - Philip C. Smith
- Division
of Pharmacoengineering and Molecular Pharmaceutics, Eshelman School
of Pharmacy, University of North Carolina
at Chapel Hill, Campus Box 7355, Chapel Hill, North Carolina 27599-7355, United States
| | - Ari Tolonen
- Admescope
Ltd, Typpitie 1, 90620 Oulu, Finland
| | - Achim Sauer
- Department
of Drug Discovery Sciences, Boehringer Ingelheim
Pharma GmbH & Co. KG, 88397 Biberach, Germany
| | - Arto Urtti
- School
of Pharmacy, University of Eastern Finland, Yliopistonranta 1 C, 70210 Kuopio, Finland
- Institute
of Chemistry, Saint Petersburg State University, Universitetskii pr. 26, 198584 Saint Petersburg, Russia
- Faculty
of Pharmacy, University of Helsinki, Viikinkaari 5 E, 00790 Helsinki, Finland
| | - Paavo Honkakoski
- School
of Pharmacy, University of Eastern Finland, Yliopistonranta 1 C, 70210 Kuopio, Finland
- Division
of Pharmacotherapy and Experimental Therapeutics, Eshelman School
of Pharmacy, University of North Carolina
at Chapel Hill, Campus Box 7569, Chapel Hill, North Carolina 27599-7569, United States
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Morse BL, Chen LH, Catlow JT, Fallon JK, Smith PC, Hillgren KM. Expansion of Knowledge on OCT1 Variant Activity In Vitro and In Vivo Using Oct1/2 -/- Mice. Front Pharmacol 2021; 12:631793. [PMID: 33658943 PMCID: PMC7917185 DOI: 10.3389/fphar.2021.631793] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2020] [Accepted: 01/11/2021] [Indexed: 11/13/2022] Open
Abstract
The role of organic cation transporter 1 (OCT1) in humans is gaining attention as data emerges regarding its role in physiology, drug exposure, and drug response. OCT1 variants with decreased in vitro function correlate well with altered exposure of multiple OCT1 substrates in variant carriers. In the current research, we investigate mechanisms behind activity of OCT1 variants in vitro by generating cell lines expressing known OCT1 variants and quantifying membrane OCT1 protein expression with corresponding OCT1 activity and kinetics. Oct knockout mice have provided additional insight into the role of Oct1 in the liver and have reproduced effects of altered OCT1 activity observed in the clinic. To assess the complex effect of Oct1 depletion on pharmacokinetics of prodrug proguanil and its active moiety cycloguanil, both of which are OCT1 substrates, Oct1/2-/- mice were used. Decreased membrane expression of OCT1 was demonstrated for all variant cell lines, although activity was substrate-dependent, as reported previously. Lack of change in activity for OCT1*2 resulted in increased intrinsic activity per pmol of OCT1 protein, particularly for sumatriptan but also for proguanil and cycloguanil. Similar to that reported in humans with decreased OCT1 function, systemic exposure of proguanil was minimally affected in Oct1/2-/- mice. However, proguanil liver partitioning and exposure decreased. Cycloguanil exposure decreased following proguanil administration in Oct1/2-/- mice, as did the systemic metabolite:parent ratio. When administered directly, systemic exposure of cycloguanil decreased slightly; however liver partitioning and exposure were decreased in Oct1/2-/- mice. Unexpectedly, following proguanil administration, the metabolite ratio in the liver changed only minimally, and liver partitioning of cycloguanil was affected in Oct1/2-/- mice to a lesser extent following proguanil administration than direct administration of cycloguanil. In conclusion, these in vitro and in vivo data offer additional complexity in understanding mechanisms of OCT1 variant activity as well as the effects of these variants in vivo. From cell lines, it is apparent that intrinsic activity is not directly related to OCT1 membrane expression. Additionally, in situations with a more complicated role of OCT1 in drug pharmacokinetics there is difficulty translating in vivo impact simply from intrinsic activity from cellular data.
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Affiliation(s)
- Bridget L. Morse
- Drug Disposition, Eli Lilly and Company, Indianapolis, IN, United States
| | - Lisa Hong Chen
- Drug Disposition, Eli Lilly and Company, Indianapolis, IN, United States
| | - John T. Catlow
- Drug Disposition, Eli Lilly and Company, Indianapolis, IN, United States
| | - John K. Fallon
- Division of Pharmacoengineering and Molecular Pharmaceutics, Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
| | - Philip C. Smith
- Division of Pharmacoengineering and Molecular Pharmaceutics, Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
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