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Jennaro TS, Puskarich MA, Flott TL, McLellan LA, Jones AE, Pai MP, Stringer KA. Kidney function as a key driver of the pharmacokinetic response to high-dose L-carnitine in septic shock. Pharmacotherapy 2023; 43:1240-1250. [PMID: 37775945 PMCID: PMC10841498 DOI: 10.1002/phar.2882] [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: 05/12/2023] [Revised: 08/22/2023] [Accepted: 08/31/2023] [Indexed: 10/01/2023]
Abstract
STUDY OBJECTIVE Levocarnitine (L-carnitine) has shown promise as a metabolic-therapeutic for septic shock, where mortality approaches 40%. However, high-dose (≥ 6 grams) intravenous supplementation results in a broad range of serum concentrations. We sought to describe the population pharmacokinetics (PK) of high-dose L-carnitine, test various estimates of kidney function, and assess the correlation of PK parameters with pre-treatment metabolites in describing drug response for patients with septic shock. DESIGN Population PK analysis was done with baseline normalized concentrations using nonlinear mixed effect models in the modeling platform Monolix. Various estimates of kidney function, patient demographics, dose received, and organ dysfunction were tested as population covariates. DATA SOURCE We leveraged serum samples and metabolomics data from a phase II trial of L-carnitine in vasopressor-dependent septic shock. Serum was collected at baseline (T0); end-of-infusion (T12); and 24, 48, and 72 h after treatment initiation. PATIENTS AND INTERVENTION Patients were adaptively randomized to receive intravenous L-carnitine (6 grams, 12 grams, or 18 grams) or placebo. MEASUREMENTS AND MAIN RESULTS The final dataset included 542 serum samples from 130 patients randomized to L-carnitine. A two-compartment model with linear elimination and a fixed volume of distribution (17.1 liters) best described the data and served as a base structural model. Kidney function estimates as a covariate on the elimination rate constant (k) reliably improved model fit. Estimated glomerular filtration rate (eGFR), based on the 2021 Chronic Kidney Disease Epidemiology collaboration (CKD-EPI) equation with creatinine and cystatin C, outperformed creatinine clearance (Cockcroft-Gault) and older CKD-EPI equations that use an adjustment for self-identified race. CONCLUSIONS High-dose L-carnitine supplementation is well-described by a two-compartment population PK model in patients with septic shock. Kidney function estimates that leverage cystatin C provided superior model fit. Future investigations into high-dose L-carnitine supplementation should consider baseline metabolic status and dose adjustments based on renal function over a fixed or weight-based dosing paradigm.
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Affiliation(s)
- Theodore S. Jennaro
- Department of Clinical Pharmacy, College of Pharmacy, University of Michigan, Ann Arbor, Michigan, USA
| | - Michael A. Puskarich
- Department of Emergency Medicine, University of Minnesota, Minneapolis, Minnesota, USA
- Department of Emergency Medicine, Hennepin County Medical Center, Minneapolis, Minnesota, USA
| | - Thomas L. Flott
- Department of Clinical Pharmacy, College of Pharmacy, University of Michigan, Ann Arbor, Michigan, USA
| | - Laura A. McLellan
- Department of Clinical Pharmacy, College of Pharmacy, University of Michigan, Ann Arbor, Michigan, USA
| | - Alan E. Jones
- Department of Emergency Medicine, University of Mississippi Medical Center, Jackson, Mississippi, USA
| | - Manjunath P. Pai
- Department of Clinical Pharmacy, College of Pharmacy, University of Michigan, Ann Arbor, Michigan, USA
| | - Kathleen A. Stringer
- Department of Clinical Pharmacy, College of Pharmacy, University of Michigan, Ann Arbor, Michigan, USA
- The Max Harry Weil Institute for Critical Care Research and Innovation, University of Michigan, Ann Arbor, Michigan, USA
- Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, School of Medicine, University of Michigan, Ann Arbor, Michigan, USA
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The Role of Organic Cation Transporters in the Pharmacokinetics, Pharmacodynamics and Drug-Drug Interactions of Tyrosine Kinase Inhibitors. Int J Mol Sci 2023; 24:ijms24032101. [PMID: 36768423 PMCID: PMC9917293 DOI: 10.3390/ijms24032101] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2022] [Revised: 01/13/2023] [Accepted: 01/16/2023] [Indexed: 01/21/2023] Open
Abstract
Tyrosine kinase inhibitors (TKIs) decisively contributed in revolutionizing the therapeutic approach to cancer, offering non-invasive, tolerable therapies for a better quality of life. Nonetheless, degree and duration of the response to TKI therapy vary depending on cancer molecular features, the ability of developing resistance to the drug, on pharmacokinetic alterations caused by germline variants and unwanted drug-drug interactions at the level of membrane transporters and metabolizing enzymes. A great deal of approved TKIs are inhibitors of the organic cation transporters (OCTs). A handful are also substrates of them. These transporters are polyspecific and highly expressed in normal epithelia, particularly the intestine, liver and kidney, and are, hence, arguably relevant sites of TKI interactions with other OCT substrates. Moreover, OCTs are often repressed in cancer cells and might contribute to the resistance of cancer cells to TKIs. This article reviews the OCT interactions with approved and in-development TKIs reported in vitro and in vivo and critically discusses the potential clinical ramifications thereof.
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Koshiba S, Motoike IN, Saigusa D, Inoue J, Aoki Y, Tadaka S, Shirota M, Katsuoka F, Tamiya G, Minegishi N, Fuse N, Kinoshita K, Yamamoto M. Identification of critical genetic variants associated with metabolic phenotypes of the Japanese population. Commun Biol 2020; 3:662. [PMID: 33177615 PMCID: PMC7659008 DOI: 10.1038/s42003-020-01383-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2020] [Accepted: 10/18/2020] [Indexed: 02/07/2023] Open
Abstract
We performed a metabolome genome-wide association study for the Japanese population in the prospective cohort study of Tohoku Medical Megabank. By combining whole-genome sequencing and nontarget metabolome analyses, we identified a large number of novel associations between genetic variants and plasma metabolites. Of the identified metabolite-associated genes, approximately half have already been shown to be involved in various diseases. We identified metabolite-associated genes involved in the metabolism of xenobiotics, some of which are from intestinal microorganisms, indicating that the identified genetic variants also markedly influence the interaction between the host and symbiotic bacteria. We also identified five associations that appeared to be female-specific. A number of rare variants that influence metabolite levels were also found, and combinations of common and rare variants influenced the metabolite levels more profoundly. These results support our contention that metabolic phenotyping provides important insights into how genetic and environmental factors provoke human diseases.
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Affiliation(s)
- Seizo Koshiba
- Tohoku Medical Megabank Organization, Tohoku University, 2-1, Seiryo-machi, Aoba-ku, Sendai, 980-8573, Japan.
- Graduate School of Medicine, Tohoku University, 2-1, Seiryo-machi, Aoba-ku, Sendai, 980-8575, Japan.
- The Advanced Research Center for Innovations in Next-Generation Medicine (INGEM), Tohoku University, 2-1, Seiryo-machi, Aoba-ku, Sendai, 980-8573, Japan.
| | - Ikuko N Motoike
- Tohoku Medical Megabank Organization, Tohoku University, 2-1, Seiryo-machi, Aoba-ku, Sendai, 980-8573, Japan
- Graduate School of Information Sciences, Tohoku University, 6-3-09, Aramaki Aza-Aoba, Aoba-ku, Sendai, 980-8579, Japan
| | - Daisuke Saigusa
- Tohoku Medical Megabank Organization, Tohoku University, 2-1, Seiryo-machi, Aoba-ku, Sendai, 980-8573, Japan
- Graduate School of Medicine, Tohoku University, 2-1, Seiryo-machi, Aoba-ku, Sendai, 980-8575, Japan
| | - Jin Inoue
- Tohoku Medical Megabank Organization, Tohoku University, 2-1, Seiryo-machi, Aoba-ku, Sendai, 980-8573, Japan
- Graduate School of Medicine, Tohoku University, 2-1, Seiryo-machi, Aoba-ku, Sendai, 980-8575, Japan
| | - Yuichi Aoki
- Tohoku Medical Megabank Organization, Tohoku University, 2-1, Seiryo-machi, Aoba-ku, Sendai, 980-8573, Japan
- Graduate School of Information Sciences, Tohoku University, 6-3-09, Aramaki Aza-Aoba, Aoba-ku, Sendai, 980-8579, Japan
| | - Shu Tadaka
- Tohoku Medical Megabank Organization, Tohoku University, 2-1, Seiryo-machi, Aoba-ku, Sendai, 980-8573, Japan
- Graduate School of Information Sciences, Tohoku University, 6-3-09, Aramaki Aza-Aoba, Aoba-ku, Sendai, 980-8579, Japan
| | - Matsuyuki Shirota
- Tohoku Medical Megabank Organization, Tohoku University, 2-1, Seiryo-machi, Aoba-ku, Sendai, 980-8573, Japan
- Graduate School of Medicine, Tohoku University, 2-1, Seiryo-machi, Aoba-ku, Sendai, 980-8575, Japan
| | - Fumiki Katsuoka
- Tohoku Medical Megabank Organization, Tohoku University, 2-1, Seiryo-machi, Aoba-ku, Sendai, 980-8573, Japan
- Graduate School of Medicine, Tohoku University, 2-1, Seiryo-machi, Aoba-ku, Sendai, 980-8575, Japan
- The Advanced Research Center for Innovations in Next-Generation Medicine (INGEM), Tohoku University, 2-1, Seiryo-machi, Aoba-ku, Sendai, 980-8573, Japan
| | - Gen Tamiya
- Tohoku Medical Megabank Organization, Tohoku University, 2-1, Seiryo-machi, Aoba-ku, Sendai, 980-8573, Japan
- Graduate School of Medicine, Tohoku University, 2-1, Seiryo-machi, Aoba-ku, Sendai, 980-8575, Japan
- The Advanced Research Center for Innovations in Next-Generation Medicine (INGEM), Tohoku University, 2-1, Seiryo-machi, Aoba-ku, Sendai, 980-8573, Japan
| | - Naoko Minegishi
- Tohoku Medical Megabank Organization, Tohoku University, 2-1, Seiryo-machi, Aoba-ku, Sendai, 980-8573, Japan
- Graduate School of Medicine, Tohoku University, 2-1, Seiryo-machi, Aoba-ku, Sendai, 980-8575, Japan
- The Advanced Research Center for Innovations in Next-Generation Medicine (INGEM), Tohoku University, 2-1, Seiryo-machi, Aoba-ku, Sendai, 980-8573, Japan
| | - Nobuo Fuse
- Tohoku Medical Megabank Organization, Tohoku University, 2-1, Seiryo-machi, Aoba-ku, Sendai, 980-8573, Japan
- Graduate School of Medicine, Tohoku University, 2-1, Seiryo-machi, Aoba-ku, Sendai, 980-8575, Japan
- The Advanced Research Center for Innovations in Next-Generation Medicine (INGEM), Tohoku University, 2-1, Seiryo-machi, Aoba-ku, Sendai, 980-8573, Japan
| | - Kengo Kinoshita
- Tohoku Medical Megabank Organization, Tohoku University, 2-1, Seiryo-machi, Aoba-ku, Sendai, 980-8573, Japan
- The Advanced Research Center for Innovations in Next-Generation Medicine (INGEM), Tohoku University, 2-1, Seiryo-machi, Aoba-ku, Sendai, 980-8573, Japan
- Graduate School of Information Sciences, Tohoku University, 6-3-09, Aramaki Aza-Aoba, Aoba-ku, Sendai, 980-8579, Japan
| | - Masayuki Yamamoto
- Tohoku Medical Megabank Organization, Tohoku University, 2-1, Seiryo-machi, Aoba-ku, Sendai, 980-8573, Japan.
- Graduate School of Medicine, Tohoku University, 2-1, Seiryo-machi, Aoba-ku, Sendai, 980-8575, Japan.
- The Advanced Research Center for Innovations in Next-Generation Medicine (INGEM), Tohoku University, 2-1, Seiryo-machi, Aoba-ku, Sendai, 980-8573, Japan.
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Abstract
The organic cation transporters (OCTs) OCT1, OCT2, OCT3, novel OCT (OCTN)1, OCTN2, multidrug and toxin exclusion (MATE)1, and MATE kidney-specific 2 are polyspecific transporters exhibiting broadly overlapping substrate selectivities. They transport organic cations, zwitterions, and some uncharged compounds and operate as facilitated diffusion systems and/or antiporters. OCTs are critically involved in intestinal absorption, hepatic uptake, and renal excretion of hydrophilic drugs. They modulate the distribution of endogenous compounds such as thiamine, L-carnitine, and neurotransmitters. Sites of expression and functions of OCTs have important impact on energy metabolism, pharmacokinetics, and toxicity of drugs, and on drug-drug interactions. In this work, an overview about the human OCTs is presented. Functional properties of human OCTs, including identified substrates and inhibitors of the individual transporters, are described. Sites of expression are compiled, and data on regulation of OCTs are presented. In addition, genetic variations of OCTs are listed, and data on their impact on transport, drug treatment, and diseases are reported. Moreover, recent data are summarized that indicate complex drug-drug interaction at OCTs, such as allosteric high-affinity inhibition of transport and substrate dependence of inhibitor efficacies. A hypothesis about the molecular mechanism of polyspecific substrate recognition by OCTs is presented that is based on functional studies and mutagenesis experiments in OCT1 and OCT2. This hypothesis provides a framework to imagine how observed complex drug-drug interactions at OCTs arise. Finally, preclinical in vitro tests that are performed by pharmaceutical companies to identify interaction of novel drugs with OCTs are discussed. Optimized experimental procedures are proposed that allow a gapless detection of inhibitory and transported drugs.
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Affiliation(s)
- Hermann Koepsell
- Institute of Anatomy and Cell Biology and Department of Molecular Plant Physiology and Biophysics, Julius-von-Sachs-Institute, University of Würzburg, Würzburg, Germany
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Jennaro TS, Puskarich MA, McCann MR, Gillies CE, Pai MP, Karnovsky A, Evans CR, Jones AE, Stringer KA. Using l-Carnitine as a Pharmacologic Probe of the Interpatient and Metabolic Variability of Sepsis. Pharmacotherapy 2020; 40:913-923. [PMID: 32688453 DOI: 10.1002/phar.2448] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
OBJECTIVE The objective of this review is to discuss the therapeutic use and differential treatment response to Levo-carnitine (l-carnitine) treatment in septic shock, and to demonstrate common lessons learned that are important to the advancement of precision medicine approaches to sepsis. We propose that significant interpatient variability in the metabolic response to l-carnitine and clinical outcomes can be used to elucidate the mechanistic underpinnings that contribute to sepsis heterogeneity. METHODS A narrative review was conducted that focused on explaining interpatient variability in l-carnitine treatment response. Relevant biological and patient-level characteristics considered include genetic, metabolic, and morphomic phenotypes; potential drug interactions; and pharmacokinetics (PKs). MAIN RESULTS Despite promising results in a phase I study, a recent phase II clinical trial of l-carnitine treatment in septic shock showed a nonsignificant reduction in mortality. However, l-carnitine treatment induces significant interpatient variability in l-carnitine and acylcarnitine concentrations over time. In particular, administration of l-carnitine induces a broad, dynamic range of serum concentrations and measured peak concentrations are associated with mortality. Applied systems pharmacology may explain variability in drug responsiveness by using patient characteristics to identify pretreatment phenotypes most likely to derive benefit from l-carnitine. Moreover, provocation of sepsis metabolism with l-carnitine offers a unique opportunity to identify metabolic response signatures associated with patient outcomes. These approaches can unmask latent metabolic pathways deranged in the sepsis syndrome and offer insight into the pathophysiology, progression, and heterogeneity of the disease. CONCLUSIONS The compiled evidence suggests there are several potential explanations for the variability in carnitine concentrations and clinical response to l-carnitine in septic shock. These serve as important confounders that should be considered in interpretation of l-carnitine clinical studies and broadly holds lessons for future clinical trial design in sepsis. Consideration of these factors is needed if precision medicine in sepsis is to be achieved.
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Affiliation(s)
- Theodore S Jennaro
- Department of Clinical Pharmacy, College of Pharmacy, University of Michigan, Ann Arbor, Michigan, USA
| | - Michael A Puskarich
- Department of Emergency Medicine, Hennepin County Medical Center, Minneapolis, Minnesota, USA.,Department of Emergency Medicine, University of Minnesota, Minneapolis, Minnesota, USA
| | - Marc R McCann
- Department of Clinical Pharmacy, College of Pharmacy, University of Michigan, Ann Arbor, Michigan, USA
| | - Christopher E Gillies
- Department of Emergency Medicine, University of Michigan, Ann Arbor, Michigan, USA.,Michigan Center for Integrative Research in Critical Care (MCIRCC), School of Medicine, University of Michigan, Ann Arbor, Michigan, USA.,Michigan Institute for Data Science, Office of Research, University of Michigan, Ann Arbor, Michigan, USA
| | - Manjunath P Pai
- Department of Clinical Pharmacy, College of Pharmacy, University of Michigan, Ann Arbor, Michigan, USA.,Michigan Center for Integrative Research in Critical Care (MCIRCC), School of Medicine, University of Michigan, Ann Arbor, Michigan, USA
| | - Alla Karnovsky
- Department of Computational Medicine and Bioinformatics, School of Medicine, University of Michigan, Ann Arbor, Michigan, USA
| | - Charles R Evans
- Michigan Regional Comprehensive Metabolomics Resource Core (MRC2), University of Michigan, Ann Arbor, Michigan, USA.,Division of Metabolism, Endocrinology and Diabetes, Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan, USA
| | - Alan E Jones
- Emergency Medicine, University of Mississippi Medical Center, Jackson, Mississippi, USA
| | - Kathleen A Stringer
- Department of Clinical Pharmacy, College of Pharmacy, University of Michigan, Ann Arbor, Michigan, USA.,Michigan Center for Integrative Research in Critical Care (MCIRCC), School of Medicine, University of Michigan, Ann Arbor, Michigan, USA.,Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, School of Medicine, University of Michigan, Ann Arbor, Michigan, USA
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6
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Karahoda R, Ceckova M, Staud F. The inhibitory effect of antiretroviral drugs on the L-carnitine uptake in human placenta. Toxicol Appl Pharmacol 2019; 368:18-25. [PMID: 30735677 DOI: 10.1016/j.taap.2019.02.002] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2018] [Revised: 01/31/2019] [Accepted: 02/05/2019] [Indexed: 12/30/2022]
Abstract
In spite of remarkable reduction in the number of children born with HIV due to antiretroviral therapy, concerns remain on the short- and long-term effects of antiretroviral drugs at the feto-placental unit. Cardio- and skeletal myopathies have been reported in children exposed to antiretroviral drugs prenatally. These conditions have also been described in perturbed placental transfer of l-carnitine, an essential co-factor in fatty acid oxidation. Due to limited fetal and placental synthesis, carnitine supply is maintained through the placental carnitine uptake from maternal blood by the organic cation/carnitine transporters OCTN1 and OCTN2 (SLC22A4 and SLC22A5, respectively). The aim of our study was to investigate potential inhibition of placental carnitine uptake by a broad range of antiretroviral drugs comprising nucleoside/nucleotide reverse transcriptase inhibitors (lamivudine, zidovudine, abacavir, tenofovir disoproxil fumarate), non-nucleoside reverse transcriptase inhibitors (rilpivirine, efavirenz, etravirine), protease inhibitors (ritonavir, lopinavir, atazanavir, saquinavir, tipranavir), integrase inhibitors (raltegravir, dolutegravir, elvitegravir) and viral entry inhibitor, maraviroc. Studies in choriocarcinoma BeWo cells and human placenta-derived models confirmed predominant expression and function of OCTN2 above OCTN1 in l-carnitine transport. Subsequent screenings in BeWo cells and isolated MVM vesicles revealed seven antiretroviral drugs as inhibitors of the Na+-dependent l-carnitine uptake, corresponding to OCTN2. Ritonavir, saquinavir and elvitegravir showed the highest inhibitory potential which was further confirmed for ritonavir and saquinavir in placental fresh villous fragments. Our data indicate possible impairment in placental and fetal supply of l-carnitine with ritonavir and saquinavir, while suggesting retained placental carnitine transport with the other antiretroviral drugs.
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Affiliation(s)
- Rona Karahoda
- Department of Pharmacology and Toxicology, Faculty of Pharmacy in Hradec Kralove, Charles University, Czech Republic
| | - Martina Ceckova
- Department of Pharmacology and Toxicology, Faculty of Pharmacy in Hradec Kralove, Charles University, Czech Republic.
| | - Frantisek Staud
- Department of Pharmacology and Toxicology, Faculty of Pharmacy in Hradec Kralove, Charles University, Czech Republic
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Bokelmann K, Brockmöller J, Tzvetkov MV. Impact of Promoter Polymorphisms on the Transcriptional Regulation of the Organic Cation Transporter OCT1 (SLC22A1). J Pers Med 2018; 8:jpm8040042. [PMID: 30544975 PMCID: PMC6313513 DOI: 10.3390/jpm8040042] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2018] [Revised: 11/20/2018] [Accepted: 12/05/2018] [Indexed: 01/12/2023] Open
Abstract
The organic cation transporter 1 (OCT1, SLC22A1) is strongly expressed in the human liver and facilitates the hepatic uptake of drugs such as morphine, metformin, tropisetron, sumatriptan and fenoterol and of endogenous substances such as thiamine. OCT1 expression is inter-individually highly variable. Here, we analyzed SNPs in the OCT1 promoter concerning their potential contribution to the variability in OCT1 expression. Using electrophoretic mobility shift and luciferase reporter gene assays in HepG2, Hep3B, and Huh7 cell lines, we identified the SNPs −1795G>A (rs6935207) and −201C>G (rs58812592) as having effects on transcription factor binding and/or promoter activity. The A-allele of the −1795G>A SNP showed allele-specific binding of the transcription factor NF-Y leading to 2.5-fold increased enhancer activity of the artificial SV40 promoter. However, the −1795G>A SNP showed no significant effects on the native OCT1 promoter activity. Furthermore, the −1795G>A SNP was not associated with the pharmacokinetics of metformin, fenoterol, sumatriptan and proguanil in healthy individuals or tropisetron efficacy in patients undergoing chemotherapy. Allele-dependent differences in USF1/2 binding and nearly total loss in OCT1 promoter activity were detected for the G-allele of −201C>G, but the SNP is apparently very rare. In conclusion, common OCT1 promoter SNPs have only minor effects on OCT1 expression.
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Affiliation(s)
- Kristin Bokelmann
- Institute of Clinical Pharmacology, University Medical Center, Georg-August-University, 37075 Göttingen, Germany.
| | - Jürgen Brockmöller
- Institute of Clinical Pharmacology, University Medical Center, Georg-August-University, 37075 Göttingen, Germany.
| | - Mladen V Tzvetkov
- Institute of Pharmacology, Center of Drug Absorption and Transport (C_DAT), University Medicine Greifswald, 17487 Greifswald, Germany.
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Adeva-Andany MM, Calvo-Castro I, Fernández-Fernández C, Donapetry-García C, Pedre-Piñeiro AM. Significance of l-carnitine for human health. IUBMB Life 2017; 69:578-594. [PMID: 28653367 DOI: 10.1002/iub.1646] [Citation(s) in RCA: 112] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2017] [Accepted: 05/24/2017] [Indexed: 12/29/2022]
Abstract
Carnitine acyltransferases catalyze the reversible transfer of acyl groups from acyl-coenzyme A esters to l-carnitine, forming acyl-carnitine esters that may be transported across cell membranes. l-Carnitine is a wáter-soluble compound that humans may obtain both by food ingestion and endogenous synthesis from trimethyl-lysine. Most l-carnitine is intracellular, being present predominantly in liver, skeletal muscle, heart and kidney. The organic cation transporter-2 facilitates l-carnitine uptake inside cells. Congenital dysfunction of this transporter causes primary l-carnitine deficiency. Carnitine acetyltransferase is involved in the export of excess acetyl groups from the mitochondria and in acetylation reactions that regulate gene transcription and enzyme activity. Carnitine octanoyltransferase is a peroxysomal enzyme required for the complete oxidation of very long-chain fatty acids and phytanic acid, a branched-chain fatty acid. Carnitine palmitoyltransferase-1 is a transmembrane protein located on the outer mitochondrial membrane where it catalyzes the conversion of acyl-coenzyme A esters to acyl-carnitine esters. Carnitine acyl-carnitine translocase transports acyl-carnitine esters across the inner mitochondrial membrane in exchange for free l-carnitine that exits the mitochondrial matrix. Carnitine palmitoyltransferase-2 is anchored on the matrix side of the inner mitochondrial membrane, where it converts acyl-carnitine esters back to acyl-coenzyme A esters, which may be used in metabolic pathways, such as mitochondrial β-oxidation. l-Carnitine enhances nonoxidative glucose disposal under euglycemic hyperinsulinemic conditions in both healthy individuals and patients with type 2 diabetes, suggesting that l-carnitine strengthens insulin effect on glycogen storage. The plasma level of acyl-carnitine esters, primarily acetyl-carnitine, increases during diabetic ketoacidosis, fasting, and physical activity, particularly high-intensity exercise. Plasma concentration of free l-carnitine decreases simultaneously under these conditions. © 2017 IUBMB Life, 69(8):578-594, 2017.
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9
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Jung ES, Park HJ, Kong KA, Choi JH, Cheon JH. Association study between OCTN1 functional haplotypes and Crohn's disease in a Korean population. THE KOREAN JOURNAL OF PHYSIOLOGY & PHARMACOLOGY : OFFICIAL JOURNAL OF THE KOREAN PHYSIOLOGICAL SOCIETY AND THE KOREAN SOCIETY OF PHARMACOLOGY 2016; 21:11-17. [PMID: 28066136 PMCID: PMC5214902 DOI: 10.4196/kjpp.2017.21.1.11] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/21/2016] [Revised: 06/10/2016] [Accepted: 07/14/2016] [Indexed: 12/19/2022]
Abstract
Crohn's disease (CD) is a chronic inflammatory bowel disease with multifactorial causes including environmental and genetic factors. Several studies have demonstrated that the organic cation/carnitine transporter 1 (OCTN1) non-synonymous variant L503F is associated with susceptibility to CD. However, it was reported that L503F is absent in Asian populations. Previously, we identified and functionally characterized genetic variants of the OCTN1 promoter region in Koreans. In that study, four variants demonstrated significant changes in promoter activity. In the present study, we determined whether four functional variants of the OCTN1 promoter play a role in the susceptibility to or clinical course of CD in Koreans. To examine it, the frequencies of the four variants of the OCTN1 promoter were determined by genotyping using DNA samples from 194 patients with CD and 287 healthy controls. Then, associations between genetic variants and the susceptibility to CD or clinical course of CD were evaluated. We found that susceptibility to CD was not associated with OCTN1 functional promoter variants or haplotypes showing altered promoter activities in in vitro assays. However, OCTN1 functional promoter haplotypes showing decreased promoter activities were significantly associated with a penetrating behavior in CD patients (HR=2.428, p=0.009). Our results suggest that the OCTN1 functional promoter haplotypes can influence the CD phenotype, although these might not be associated with susceptibility to this disease.
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Affiliation(s)
- Eun Suk Jung
- Department of Pharmacology, Brain Korea 21 PLUS Project for Medical Sciences, Severance Biomedical Science Institute, Yonsei University College of Medicine, Seoul 03722, Korea.; Department of Internal Medicine and Institute of Gastroenterology, Yonsei University College of Medicine, Seoul 03722, Korea
| | - Hyo Jin Park
- Department of Pharmacology, Tissue Injury Defense Research Center, School of Medicine, Ewha Womans University, Seoul 07985, Korea
| | - Kyoung Ae Kong
- Clinical Trial Center, Ewha Womans University Medical Center, Seoul 07985, Korea
| | - Ji Ha Choi
- Department of Pharmacology, Tissue Injury Defense Research Center, School of Medicine, Ewha Womans University, Seoul 07985, Korea
| | - Jae Hee Cheon
- Department of Internal Medicine and Institute of Gastroenterology, Yonsei University College of Medicine, Seoul 03722, Korea
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10
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ABC transporter polymorphisms are associated with irinotecan pharmacokinetics and neutropenia. THE PHARMACOGENOMICS JOURNAL 2016; 18:35-42. [PMID: 27845419 DOI: 10.1038/tpj.2016.75] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/29/2015] [Revised: 05/09/2016] [Accepted: 08/25/2016] [Indexed: 12/22/2022]
Abstract
Neutropenia is a common dose-limiting toxicity associated with irinotecan treatment. Although UGT1A1 variants have been associated with neutropenia, a fraction of neutropenia risk remains unaccounted for. To identify additional genetic markers contributing to variability in irinotecan pharmacokinetics and neutropenia, a regression analysis was performed in 78 irinotecan-treated patients to analyze comprehensively three hepatic efflux transporter genes (ABCB1, ABCC1 and ABCG2). rs6498588 (ABCC1) and rs12720066 (ABCB1) were associated with increased SN-38 exposure, and rs17501331 (ABCC1) and rs12720066 were associated with lower absolute neutrophil count nadir. rs6498588 and a variant in high linkage disequilibrium are located in transcriptionally active regions or are predicted to alter transcription factor binding sites. While enhancer activity was not evident in vitro for genomic regions containing these single-nucleotide polymorphisms, rs6498588 was significantly associated with ABCC1 expression in human liver. These results suggest that genetic variation in ABCC1 and ABCB1 may contribute to irinotecan-induced neutropenia by altering expression of transporters involved in irinotecan metabolite disposition.
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Park HJ, Jung ES, Kong KA, Park EM, Cheon JH, Choi JH. Identification of OCTN2 variants and their association with phenotypes of Crohn's disease in a Korean population. Sci Rep 2016; 6:22887. [PMID: 26965072 PMCID: PMC4786794 DOI: 10.1038/srep22887] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2015] [Accepted: 02/23/2016] [Indexed: 12/19/2022] Open
Abstract
Crohn’s disease (CD) is a chronic inflammatory bowel disease and a genetic variant in the OCTN2, g.-207G > C is significantly associated with CD susceptibility. This study was aimed to identify novel OCTN2 functional promoter variants and their roles in transcriptional regulation using various in vitro assays. In addition, we investigated the association between OCTN2 genotypes and CD through genetic analysis using DNA samples from 193 patients with CD and 281 healthy controls. Among the three major promoter haplotypes of OCTN2 identified, one haplotype, H3, showed a significant decrease in promoter activity: two polymorphisms in H3 were associated with a significant reduction in promoter activity. In particular, we found that the reduced transcriptional activity of those two polymorphisms results from a reduction in the binding affinity of the activators, NF-E2 and YY1, to the OCTN2 promoter. The functional haplotype of the OCTN2 promoter was associated with clinical course of CD such as the disease behavior and need for surgery. However, genetic variants or haplotypes of OCTN2 did not affect the susceptibility to CD. Our results suggest that a common promoter haplotype of OCTN2 regulates the transcriptional rate of OCTN2 and influences the clinical course of CD.
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Affiliation(s)
- Hyo Jin Park
- Department of Pharmacology, Tissue Injury Defense Research Center, School of Medicine, Ewha Womans University, Seoul, 07985, Korea
| | - Eun Suk Jung
- Department of Pharmacology, Brain Korea 21 PLUS Project for Medical Sciences, Severance Biomedical Science Institute, Yonsei University College of Medicine, Seoul, 03722, Korea.,Department of Internal Medicine and Institute of Gastroenterology, Yonsei University College of Medicine, Seoul, 03722, Korea
| | - Kyoung Ae Kong
- Clinical Trial Center, Ewha Womans University Medical Center, Seoul, 07985, Korea
| | - Eun-Mi Park
- Department of Pharmacology, Tissue Injury Defense Research Center, School of Medicine, Ewha Womans University, Seoul, 07985, Korea
| | - Jae Hee Cheon
- Department of Internal Medicine and Institute of Gastroenterology, Yonsei University College of Medicine, Seoul, 03722, Korea
| | - Ji Ha Choi
- Department of Pharmacology, Tissue Injury Defense Research Center, School of Medicine, Ewha Womans University, Seoul, 07985, Korea
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Droździk M, Oronowicz K, Piasecka M, Kazienko A, Rosiak A, Gill K, Dziedziejko V, Safranow K, Kurzawa R, Kurzawski M. Organic cation/carnitine transporter OCTN2 (SLC22A5) -207C>G (rs2631367) polymorphism is not associated with male infertility. Reprod Biol 2015; 15:178-83. [PMID: 26370461 DOI: 10.1016/j.repbio.2015.06.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2015] [Revised: 05/05/2015] [Accepted: 06/06/2015] [Indexed: 10/23/2022]
Abstract
Carnitine is an important factor in the initiation of progressive sperm motility and end stage of sperm maturation. The compound is transported by an organic cation/carnitine transporter (OCTN2), which is expressed in the male reproductive system. OCTN2 is encoded by SLC22A5 gene with proven -207C>G functional polymorphism. The aim of the case-control study was to investigate a potential association between the -207C>G SLC22A5 polymorphism and male infertility. The -207C>G SLC22A5 polymorphism was determined by means of TaqMan assay in 206 infertile Caucasian males and 256 ethnically matched controls. Besides genotyping study, sperm mitochondrial function was assessed using NADH-dependent NBT assay. The distribution of SLC22A5 genotypes in infertile men was as follows: CC - 29.6%, CG - 53.9%, GG - 16.5% and in fertile men: CC - 32.0%, CG - 50.0%, GG - 18.0%, and was comparable in both evaluated groups. Likewise, the studied polymorphism did not affect sperm mitochondrial function. The results of the current study demonstrated that -207C>G polymorphism of the SLC22A5 gene is not associated with male infertility.
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Affiliation(s)
- Marek Droździk
- Department of Experimental and Clinical Pharmacology, Pomeranian Medical University, Powstańców Wlkp. 72, 70-111 Szczecin, Poland
| | - Katarzyna Oronowicz
- Department of Obstetrics and Gynecology, County Hospital, Mączna 4, 70-780 Szczecin, Poland
| | - Malgorzata Piasecka
- Department of Histology and Developmental Biology, Pomeranian Medical University, Żołnierska 48, 71-210 Szczecin, Poland
| | - Anna Kazienko
- Department of Reproductive Medicine and Gynecology, Pomeranian Medical University, Siedlecka 2, Police, Poland
| | - Aleksandra Rosiak
- Department of Histology and Developmental Biology, Pomeranian Medical University, Żołnierska 48, 71-210 Szczecin, Poland; VitroLive Fertility Clinic, Kasprzaka 2A, 71-074 Szczecin, Poland
| | - Kamil Gill
- Department of Histology and Developmental Biology, Pomeranian Medical University, Żołnierska 48, 71-210 Szczecin, Poland
| | - Violetta Dziedziejko
- Department of Biochemistry and Medical Chemistry, Pomeranian Medical University, Powstańców Wlkp. 72, 70-111 Szczecin, Poland
| | - Krzysztof Safranow
- Department of Biochemistry and Medical Chemistry, Pomeranian Medical University, Powstańców Wlkp. 72, 70-111 Szczecin, Poland
| | - Rafał Kurzawa
- Department of Reproductive Medicine and Gynecology, Pomeranian Medical University, Siedlecka 2, Police, Poland; VitroLive Fertility Clinic, Kasprzaka 2A, 71-074 Szczecin, Poland
| | - Mateusz Kurzawski
- Department of Experimental and Clinical Pharmacology, Pomeranian Medical University, Powstańców Wlkp. 72, 70-111 Szczecin, Poland.
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Residual OCTN2 transporter activity, carnitine levels and symptoms correlate in patients with primary carnitine deficiency. Mol Genet Metab Rep 2014; 1:241-248. [PMID: 27896095 PMCID: PMC5121291 DOI: 10.1016/j.ymgmr.2014.04.008] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2014] [Accepted: 04/25/2014] [Indexed: 12/30/2022] Open
Abstract
BACKGROUND The prevalence of primary carnitine deficiency (PCD) in the Faroe Islands is the highest reported in the world (1:300). Serious symptoms related to PCD, e.g. sudden death, have previously only been associated to the c.95A > G/c.95A > G genotype in the Faroe Islands. We report and characterize novel mutations associated with PCD in the Faroese population and report and compare free carnitine levels and OCTN2 transport activities measured in fibroblasts from PCD patients with different genotypes. METHODS Genetic analyses were used to identify novel mutations, and carnitine uptake analyses in cultured skin fibroblasts from selected patients were used to examine residual OCTN2 transporter activities of the various genotypes. RESULTS Four different mutations, including the unpublished c.131C > T (p.A44V), the novel splice mutation c.825-52G > A and a novel risk-haplotype (RH) were identified in the Faroese population. The two most prevalent genotypes were c.95A > G/RH (1:600) and c.95A > G/c.95A > G (1:1300). Patients homozygous for the c.95A > G mutation had both the significantly (p < 0.01) lowest mean free carnitine level at 2.03 (SD 0.66) μmol/L and lowest residual OCTN2 transporter activity (4% of normal). There was a significant positive correlation between free carnitine levels and residual OCTN2 transporter activities in PCD patients (R2 = 0.430, p < 0.01). CONCLUSION There was a significant positive correlation between carnitine levels and OCTN2 transporter activities. The c.95A > G/c.95A > G genotype had the significantly lowest mean free carnitine level and residual OCTN2 transporter activity.
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Park HJ, Choi JH. Identification and Functional Characterization of Novel Genetic Variations in the OCTN1 Promoter. THE KOREAN JOURNAL OF PHYSIOLOGY & PHARMACOLOGY : OFFICIAL JOURNAL OF THE KOREAN PHYSIOLOGICAL SOCIETY AND THE KOREAN SOCIETY OF PHARMACOLOGY 2014; 18:169-75. [PMID: 24757380 PMCID: PMC3994305 DOI: 10.4196/kjpp.2014.18.2.169] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/22/2014] [Revised: 03/02/2014] [Accepted: 03/03/2014] [Indexed: 01/27/2023]
Abstract
Human organic cation/carnitine transporter 1 (OCTN1) plays an important role in the transport of drugs and endogenous substances. It is known that a missense variant of OCTN1 is significantly associated with Crohn's disease susceptibility. This study was performed to identify genetic variants of the OCTN1 promoter in Korean individuals and to determine their functional effects. First, the promoter region of OCTN1 was directly sequenced using genomic DNA samples from 48 healthy Koreans. OCTN1 promoter activity was then measured using a luciferase reporter assay in HCT-116 cells. Seven variants of the OCTN1 promoter were identified, two of which were novel. There were also four major OCTN1 promoter haplotypes. Three haplotypes (H1, H3, and H4) showed decreased transcriptional activity, which was reduced by 22.9%, 23.0%, and 44.6%, respectively (p<0.001), compared with the reference haplotype (H2). Transcription factor binding site analyses and gel shift assays revealed that NF-Y could bind to the region containing g.-1875T>A, a variant present in H3, and that the binding affinity of NF-Y was higher for the g.-1875T allele than for the g.-1875A allele. NF-Y could also repress OCTN1 transcription. These data suggest that three OCTN1 promoter haplotypes could regulate OCTN1 transcription. To our knowledge, this is the first study to identify functional variants of the OCTN1 promoter.
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Affiliation(s)
- Hyo Jin Park
- Department of Pharmacology, Tissue Injury Defense Research Center, School of Medicine, Ewha Womans University, Seoul 158-710, Korea
| | - Ji Ha Choi
- Department of Pharmacology, Tissue Injury Defense Research Center, School of Medicine, Ewha Womans University, Seoul 158-710, Korea
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15
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Koepsell H. The SLC22 family with transporters of organic cations, anions and zwitterions. Mol Aspects Med 2013; 34:413-35. [PMID: 23506881 DOI: 10.1016/j.mam.2012.10.010] [Citation(s) in RCA: 275] [Impact Index Per Article: 25.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2012] [Accepted: 08/18/2012] [Indexed: 12/14/2022]
Abstract
The SLC22 family contains 13 functionally characterized human plasma membrane proteins each with 12 predicted α-helical transmembrane domains. The family comprises organic cation transporters (OCTs), organic zwitterion/cation transporters (OCTNs), and organic anion transporters (OATs). The transporters operate as (1) uniporters which mediate facilitated diffusion (OCTs, OCTNs), (2) anion exchangers (OATs), and (3) Na(+)/zwitterion cotransporters (OCTNs). They participate in small intestinal absorption and hepatic and renal excretion of drugs, xenobiotics and endogenous compounds and perform homeostatic functions in brain and heart. Important endogeneous substrates include monoamine neurotransmitters, l-carnitine, α-ketoglutarate, cAMP, cGMP, prostaglandins, and urate. It has been shown that mutations of the SLC22 genes encoding these transporters cause specific diseases like primary systemic carnitine deficiency and idiopathic renal hypouricemia and are correlated with diseases such as Crohn's disease and gout. Drug-drug interactions at individual transporters may change pharmacokinetics and toxicities of drugs.
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Affiliation(s)
- Hermann Koepsell
- University of Würzburg, Institute of Anatomy and Cell Biology, Koellikerstr. 6, 97070 Würzburg, Germany.
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16
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Toh DSL, Cheung FSG, Murray M, Pern TK, Lee EJD, Zhou F. Functional Analysis of Novel Variants in the Organic Cation/Ergothioneine Transporter 1 Identified in Singapore Populations. Mol Pharm 2013; 10:2509-16. [DOI: 10.1021/mp400193r] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Affiliation(s)
- Dorothy Su Lin Toh
- Faculty of Pharmacy, University of Sydney, NSW 2006, Australia
- Department of Pharmacology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 119245
| | | | - Michael Murray
- Faculty of Pharmacy, University of Sydney, NSW 2006, Australia
- Discipline of Pharmacology, School
of Medical Sciences, The University of Sydney, NSW 2006, Australia
| | - Tan Kuan Pern
- Bioinformatics Institute, Agency for Science, Technology and Research (A*STAR), Singapore 138632
| | - Edmund Jon Deoon Lee
- Department of Pharmacology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 119245
| | - Fanfan Zhou
- Faculty of Pharmacy, University of Sydney, NSW 2006, Australia
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17
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Yee SW, Nguyen AN, Brown C, Savic RM, Zhang Y, Castro RA, Cropp CD, Choi JH, Singh D, Tahara H, Stocker SL, Huang Y, Brett CM, Giacomini KM. Reduced renal clearance of cefotaxime in asians with a low-frequency polymorphism of OAT3 (SLC22A8). J Pharm Sci 2013; 102:3451-7. [PMID: 23649425 DOI: 10.1002/jps.23581] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2012] [Revised: 03/29/2013] [Accepted: 04/12/2013] [Indexed: 12/31/2022]
Abstract
Organic anion transporter 3 (OAT3, SLC22A8), a transporter expressed on the basolateral membrane of the proximal tubule, plays a critical role in the renal excretion of organic anions including many therapeutic drugs. The goal of this study was to evaluate the in vivo effects of the OAT3-Ile305Phe variant (rs11568482), present at 3.5% allele frequency in Asians, on drug disposition with a focus on cefotaxime, a cephalosporin antibiotic. In HEK293-Flp-In cells, the OAT3-Ile305Phe variant had a lower maximum cefotaxime transport activity, Vmax , [159 ± 3 nmol*(mg protein)(-1) /min (mean ± SD)] compared with the reference OAT3 [305 ± 28 nmol*(mg protein)(-1) /min, (mean ± SD), p < 0.01], whereas the Michaelis-Menten constant values (Km ) did not differ. In healthy volunteers, we found volunteers that were heterozygous for the Ile305Phe variant and had a significantly lower cefotaxime renal clearance (CLR ; mean ± SD: 84.8 ± 32.1 mL/min, n = 5) compared with volunteers that were homozygous for the reference allele (158 ± 44.1 mL/min, n = 10; p = 0.006). Furthermore, the net secretory component of cefotaxime renal clearance (CLsec ) was reduced in volunteers heterozygous for the variant allele [33.3 ± 31.8 mL/min (mean ± SD)] compared with volunteers homozygous for the OAT3 reference allele [97.0 ± 42.2 mL/min (mean ± SD), p = 0.01]. In summary, our study suggests that a low-frequency reduced-function polymorphism of OAT3 associates with reduced cefotaxime CLR and CL(sec) .
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Affiliation(s)
- Sook Wah Yee
- Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, California, USA
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18
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Chen L, Hong C, Chen EC, Yee SW, Xu L, Almof EU, Wen C, Fujii K, Johns SJ, Stryke D, Ferrin TE, Simko J, Chen X, Costello JF, Giacomini KM. Genetic and epigenetic regulation of the organic cation transporter 3, SLC22A3. THE PHARMACOGENOMICS JOURNAL 2012; 13:110-20. [PMID: 22231567 PMCID: PMC3396779 DOI: 10.1038/tpj.2011.60] [Citation(s) in RCA: 66] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Human organic cation transporter 3 (OCT3 and SLC22A3) mediates the uptake of many important endogenous amines and basic drugs in a variety of tissues. OCT3 is identified as one of the important risk loci for prostate cancer, and is markedly underexpressed in aggressive prostate cancers. The goal of this study was to identify genetic and epigenetic factors in the promoter region that influence the expression level of OCT3. Haplotypes that contained the common variants, g.-81G>delGA (rs60515630) (minor allele frequency 11.5% in African American) and g.-2G>A (rs555754) (minor allele frequency>30% in all ethnic groups) showed significant increases in luciferase reporter activities and exhibited stronger transcription factor-binding affinity than the haplotypes that contained the major alleles. Consistent with the reporter assays, OCT3 messenger RNA expression levels were significantly higher in Asian (P<0.001) and Caucasian (P<0.05) liver samples from individuals who were homozygous for g.-2A/A in comparison with those homozygous for the g.-2G/G allele. Studies revealed that the methylation level in the basal promoter region of OCT3 was associated with OCT3 expression level and tumorigenesis capability in various prostate cancer cell lines. The methylation level of the OCT3 promoter was higher in 62% of prostate tumor samples compared with matched normal samples. Our studies demonstrate that genetic polymorphisms in the proximal promoter region of OCT3 alter the transcription rate of the gene and may be associated with altered expression levels of OCT3 in human liver. Aberrant methylation contributes to the reduced expression of OCT3 in prostate cancer.
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Affiliation(s)
- L Chen
- Department of Bioengineering and Therapeutic Sciences, University of California San Francisco, CA 94158, USA
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Functional analysis of pharmacogenetic variants of human organic cation/carnitine transporter 2 (hOCTN2) identified in Singaporean populations. Biochem Pharmacol 2011; 82:1692-9. [DOI: 10.1016/j.bcp.2011.08.008] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2011] [Revised: 08/05/2011] [Accepted: 08/05/2011] [Indexed: 12/30/2022]
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20
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Matsson P, Yee SW, Markova S, Morrissey K, Jenkins G, Xuan J, Jorgenson E, Kroetz DL, Giacomini KM. Discovery of regulatory elements in human ATP-binding cassette transporters through expression quantitative trait mapping. THE PHARMACOGENOMICS JOURNAL 2011; 12:214-26. [PMID: 21383772 PMCID: PMC3325368 DOI: 10.1038/tpj.2011.8] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
ATP-Binding Cassette (ABC) membrane transporters determine the disposition of many drugs, metabolites and endogenous compounds. Coding region variation in ABC transporters is the cause of many genetic disorders, but much less is known about the genetic basis and functional outcome of ABC transporter expression level variation. We used genotype and mRNA transcript level data from human lymphoblastoid cell lines to assess population and gender differences in ABC transporter expression, and to guide the discovery of genomic regions involved in transcriptional regulation. Nineteen of 49 ABC genes were differentially expressed between individuals of African, Asian and European descent suggesting an important influence of race on expression level of ABC transporters. Twenty-four significant associations were found between transporter transcript levels and proximally located genetic variants. Several of the associations were experimentally validated in reporter assays. Through influencing ABC expression levels, these SNPs may affect disease susceptibility and response to drugs.
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Affiliation(s)
- P Matsson
- Department of Bioengineering and Therapeutic Sciences, University of California San Francisco, San Francisco, CA, USA
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21
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Functional characterization of liver enhancers that regulate drug-associated transporters. Clin Pharmacol Ther 2011; 89:571-8. [PMID: 21368754 DOI: 10.1038/clpt.2010.353] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Little is known about how genetic variations in enhancers influence drug response. In this study, we investigated whether nucleotide variations in enhancers that regulate drug transporters can alter their expression levels. Using comparative genomics and liver-specific transcription factor binding site (TFBS) analyses, we identified evolutionary conserved regions (ECRs) surrounding nine liver membrane transporters that interact with commonly used pharmaceuticals. The top 50 ECRs were screened for enhancer activity in vivo, of which five--located around ABCB11, SLC10A1, SLCO1B1, SLCO1A2, and SLC47A1--exhibited significant enhancer activity. Common variants identified in a large ethnically diverse cohort (n = 272) were assayed for differential enhancer activity, and three variants were found to have significant effects on reporter activity as compared with the reference allele. In addition, one variant was associated with reduced SLCO1A2 mRNA expression levels in human liver tissues, and another was associated with increased methotrexate (MTX) clearance in patients. This work provides a general model for the rapid characterization of liver enhancers and identifies associations between enhancer variants and drug response.
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Wang J, Wang X, Yang H, Wu D, Wang L, Qian J. Contribution of the IBD5 locus to inflammatory bowel disease: a meta-analysis. Hum Genet 2011; 129:597-609. [PMID: 21279723 DOI: 10.1007/s00439-011-0952-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2010] [Accepted: 01/17/2011] [Indexed: 12/13/2022]
Abstract
To evaluate the association of the IBD5 locus to the predisposition of inflammatory bowel diseases (IBDs), a series of meta-analyses between five IBD5 variants (OCTN1 C1672T, OCTN2 G-207C, OCTN1/2 TC haplotype, IGR2096a_1, IGR2198a_1 and IGR2230a_1) and Crohn's disease (CD) and ulcerative colitis (UC) were performed, which included a total of 26 studies. Overall, five IBD5 variants in a per-allele model of inheritance were significantly associated with elevated CD risk (for OCTN1: OR = 1.23, 95% CI = 1.16-1.30, P < 0.001; for OCTN2: OR = 1.20, 95% CI = 1.11-1.30, P < 0.001; for IGR2096a_1: OR = 1.36, 95% CI = 1.24-1.46, P < 0.001; for IGR2198a_1: OR = 1.34, 95% CI = 1.24-1.46, P < 0.001; for IGR2230a_1: OR = 1.35, 95% CI = 1.23-1.48, P < 0.001) and OCTN1/2 TC haplotype (OR = 1.32, 95% CI = 1.22-1.43, P < 0.001). In the subgroup analysis, the statistically significant associations were also observed in adult- and pediatric-onset CD and in Caucasians for five IBD5 variants and the OCTN1/2 TC haplotype. A statistically significant increase in the risk of UC was detected in a recessive model of inheritances for OCTN1 (OR = 1.23, 95% CI = 1.08-1.40, P < 0.001), OCTN2 (OR = 1.18, 95% CI = 1.05-1.33, P = 0.006), IGR2096a_1 (OR = 1.37, 95% CI = 1.15-1.62, P < 0.001) and IGR2198a_1 (OR = 1.35, 95% CI = 1.10-1.66, P = 0.004); the increased risks of UC were maintained in the adult and Caucasian subgroups, but not the pediatric subgroup. In summary, our results suggested that the IBD5 locus contributes to the susceptibility of CD in a per-allele manner in adults, children and Caucasians, and the locus contributes to the susceptibility of UC in a recessive manner in adult and Caucasian populations.
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Affiliation(s)
- Jian Wang
- Department of Gastroenterology, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing 100730, People's Republic of China
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Pollex EK, Hutson JR. Genetic polymorphisms in placental transporters: implications for fetal drug exposure to oral antidiabetic agents. Expert Opin Drug Metab Toxicol 2011; 7:325-39. [DOI: 10.1517/17425255.2011.553188] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
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Yee SW, Chen L, Giacomini KM. Pharmacogenomics of membrane transporters: past, present and future. Pharmacogenomics 2010; 11:475-9. [PMID: 20350125 DOI: 10.2217/pgs.10.22] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Membrane transporters are major determinants of the absorption, distribution and elimination of many of the most commonly used drugs. In the past decade, the field of membrane transporter pharmacogenomics has undergone enormous growth. In particular, functional genomic and clinical studies have provided new information regarding the contribution of coding variants in transporters to drug disposition and response. With continuing advances in sequencing technologies and large-scale human variation studies, over the next decade, knowledge in the field will be transformed. In particular, functional variants in noncoding regions of transporters will be discovered, and large clinical studies will result in the identification of variants in multiple genes, including transporter genes, which contribute to variation in clinical drug response.
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Affiliation(s)
- Sook Wah Yee
- School of Pharmacy, University of California San Francisco, CA 94143-2911, USA
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25
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Kroetz DL, Ahituv N, Burchard EG, Guo S, Sali A, Giacomini KM. Institutional Profile: The University of California Pharmacogenomics Center: at the interface of genomics, biological mechanisms and drug therapy. Pharmacogenomics 2010; 10:1569-76. [PMID: 19842929 DOI: 10.2217/pgs.09.119] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The Pharmacogenomics Center of the University of California, San Francisco (CA, USA) fosters research and educational activities focused on the genomic basis for variation in drug response. Investigators in the Center conduct multidisciplinary and multicenter research on a diverse array of clinically used drugs with the goal of understanding the genetic factors that contribute to variation in therapeutic and adverse drug response. The Center houses the large NIH-supported Pharmacogenomics of Membrane Transporters Project, which is a leader in understanding genetic variation in membrane transporters that are important in clinical drug response. Center investigators study racially and ethnically diverse populations, are pioneers in the education of PharmD, MD and PhD students in pharmacogenomics, and have led the establishment of unique graduate and postdoctoral training programs focused on pharmacogenomics. A key emphasis of the Center is on biological mechanisms with a goal of facilitating the development of safer and more effective medications.
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Affiliation(s)
- Deanna L Kroetz
- Department of Bioengineering and Therapeutic Sciences, Schools of Pharmacy and Medicine, University of California San Francisco, San Francisco, CA, USA
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Welsh M, Mangravite L, Medina MW, Tantisira K, Zhang W, Huang RS, McLeod H, Dolan ME. Pharmacogenomic discovery using cell-based models. Pharmacol Rev 2010; 61:413-29. [PMID: 20038569 DOI: 10.1124/pr.109.001461] [Citation(s) in RCA: 99] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Quantitative variation in response to drugs in human populations is multifactorial; genetic factors probably contribute to a significant extent. Identification of the genetic contribution to drug response typically comes from clinical observations and use of classic genetic tools. These clinical studies are limited by our inability to control environmental factors in vivo and the difficulty of manipulating the in vivo system to evaluate biological changes. Recent progress in dissecting genetic contribution to natural variation in drug response through the use of cell lines has been made and is the focus of this review. A general overview of current cell-based models used in pharmacogenomic discovery and validation is included. Discussion includes the current approach to translate findings generated from these cell-based models into the clinical arena and the use of cell lines for functional studies. Specific emphasis is given to recent advances emerging from cell line panels, including the International HapMap Project and the NCI60 cell panel. These panels provide a key resource of publicly available genotypic, expression, and phenotypic data while allowing researchers to generate their own data related to drug treatment to identify genetic variation of interest. Interindividual and interpopulation differences can be evaluated because human lymphoblastoid cell lines are available from major world populations of European, African, Chinese, and Japanese ancestry. The primary focus is recent progress in the pharmacogenomic discovery area through ex vivo models.
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Affiliation(s)
- Marleen Welsh
- Department of Medicine, University of Chicago, Chicago, Illinois 60637, USA
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The pharmacogenomics of membrane transporters project: research at the interface of genomics and transporter pharmacology. Clin Pharmacol Ther 2009; 87:109-16. [PMID: 19940846 DOI: 10.1038/clpt.2009.226] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Since the cloning of the first membrane transporter, our understanding of the role of transporters in clinical drug disposition and response has grown enormously. In parallel, large-scale genome-wide variation studies and the emerging field of pharmacogenomics have ushered in a new understanding of variations in drug response. At the crossroads of pharmacogenomics and transporter biology is the National Institutes of Health-funded Pharmacogenomics of Membrane Transporters (PMT) project, centered at the University of California, San Francisco.
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Hesselson SE, Matsson P, Shima JE, Fukushima H, Yee SW, Kobayashi Y, Gow JM, Ha C, Ma B, Poon A, Johns SJ, Stryke D, Castro RA, Tahara H, Choi JH, Chen L, Picard N, Sjödin E, Roelofs MJE, Ferrin TE, Myers R, Kroetz DL, Kwok PY, Giacomini KM. Genetic variation in the proximal promoter of ABC and SLC superfamilies: liver and kidney specific expression and promoter activity predict variation. PLoS One 2009; 4:e6942. [PMID: 19742321 PMCID: PMC2735003 DOI: 10.1371/journal.pone.0006942] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2009] [Accepted: 08/05/2009] [Indexed: 12/11/2022] Open
Abstract
Membrane transporters play crucial roles in the cellular uptake and efflux of an array of small molecules including nutrients, environmental toxins, and many clinically used drugs. We hypothesized that common genetic variation in the proximal promoter regions of transporter genes contribute to observed variation in drug response. A total of 579 polymorphisms were identified in the proximal promoters (−250 to +50 bp) and flanking 5′ sequence of 107 transporters in the ATP Binding Cassette (ABC) and Solute Carrier (SLC) superfamilies in 272 DNA samples from ethnically diverse populations. Many transporter promoters contained multiple common polymorphisms. Using a sliding window analysis, we observed that, on average, nucleotide diversity (π) was lowest at approximately 300 bp upstream of the transcription start site, suggesting that this region may harbor important functional elements. The proximal promoters of transporters that were highly expressed in the liver had greater nucleotide diversity than those that were highly expressed in the kidney consistent with greater negative selective pressure on the promoters of kidney transporters. Twenty-one promoters were evaluated for activity using reporter assays. Greater nucleotide diversity was observed in promoters with strong activity compared to promoters with weak activity, suggesting that weak promoters are under more negative selective pressure than promoters with high activity. Collectively, these results suggest that the proximal promoter region of membrane transporters is rich in variation and that variants in these regions may play a role in interindividual variation in drug disposition and response.
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Affiliation(s)
- Stephanie E. Hesselson
- Cardiovascular Research Institute, University of California San Francisco, San Francisco, California, United States of America
| | - Pär Matsson
- Department of Bioengineering and Therapeutic Sciences, University of California San Francisco, San Francisco, California, United States of America
| | - James E. Shima
- Department of Bioengineering and Therapeutic Sciences, University of California San Francisco, San Francisco, California, United States of America
| | - Hisayo Fukushima
- Department of Bioengineering and Therapeutic Sciences, University of California San Francisco, San Francisco, California, United States of America
| | - Sook Wah Yee
- Department of Bioengineering and Therapeutic Sciences, University of California San Francisco, San Francisco, California, United States of America
| | - Yuya Kobayashi
- Department of Genetics, Stanford University School of Medicine, Stanford, California, United States of America
| | - Jason M. Gow
- Department of Bioengineering and Therapeutic Sciences, University of California San Francisco, San Francisco, California, United States of America
| | - Connie Ha
- Cardiovascular Research Institute, University of California San Francisco, San Francisco, California, United States of America
| | - Benjamin Ma
- Cardiovascular Research Institute, University of California San Francisco, San Francisco, California, United States of America
| | - Annie Poon
- Cardiovascular Research Institute, University of California San Francisco, San Francisco, California, United States of America
| | - Susan J. Johns
- Pharmaceutical Chemistry, University of California San Francisco, San Francisco, California, United States of America
| | - Doug Stryke
- Pharmaceutical Chemistry, University of California San Francisco, San Francisco, California, United States of America
| | - Richard A. Castro
- Department of Bioengineering and Therapeutic Sciences, University of California San Francisco, San Francisco, California, United States of America
| | - Harunobu Tahara
- Department of Bioengineering and Therapeutic Sciences, University of California San Francisco, San Francisco, California, United States of America
| | - Ji Ha Choi
- Department of Bioengineering and Therapeutic Sciences, University of California San Francisco, San Francisco, California, United States of America
| | - Ligong Chen
- Department of Bioengineering and Therapeutic Sciences, University of California San Francisco, San Francisco, California, United States of America
| | - Nicolas Picard
- Department of Bioengineering and Therapeutic Sciences, University of California San Francisco, San Francisco, California, United States of America
| | - Elin Sjödin
- Department of Bioengineering and Therapeutic Sciences, University of California San Francisco, San Francisco, California, United States of America
| | - Maarke J. E. Roelofs
- Department of Bioengineering and Therapeutic Sciences, University of California San Francisco, San Francisco, California, United States of America
| | - Thomas E. Ferrin
- Pharmaceutical Chemistry, University of California San Francisco, San Francisco, California, United States of America
| | - Richard Myers
- Department of Genetics, Stanford University School of Medicine, Stanford, California, United States of America
| | - Deanna L. Kroetz
- Department of Bioengineering and Therapeutic Sciences, University of California San Francisco, San Francisco, California, United States of America
| | - Pui-Yan Kwok
- Cardiovascular Research Institute, University of California San Francisco, San Francisco, California, United States of America
| | - Kathleen M. Giacomini
- Department of Bioengineering and Therapeutic Sciences, University of California San Francisco, San Francisco, California, United States of America
- * E-mail:
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