1
|
Hosooka A, Yasujima T, Murata A, Yamashiro T, Yuasa H. Identification of human-specific amino acid residues governing atenolol transport via organic cation transporter 2. Biochem Pharmacol 2024; 229:116514. [PMID: 39236937 DOI: 10.1016/j.bcp.2024.116514] [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: 04/18/2024] [Revised: 08/10/2024] [Accepted: 08/29/2024] [Indexed: 09/07/2024]
Abstract
Organic cation transporter 2 (OCT2/SLC22A2) is predominantly localized on the basolateral membranes of renal tubular epithelial cells and plays a crucial role in the renal secretion of various cationic drugs. Although variations in substrate selectivity among renal organic cation transport systems across species have been reported, the characteristics of OCT2 remain unclear. In this study, we demonstrated that atenolol, a β1-selective adrenergic antagonist, is transported almost exclusively by human OCT2, contrasting with OCT2s from other selected species. Using chimeric constructs between human OCT2 (hOCT2) and the highly homologous monkey OCT2 (monOCT2), along with site-directed mutagenesis, we identified non-conserved amino acids Val8, Ala31, Ala34, Tyr222, Tyr245, Ala270, Ile394, and Leu503 as pivotal for hOCT2-mediated atenolol transport. Kinetic analysis revealed that atenolol was transported by hOCT2 with a 12-fold lower affinity than MPP+, a typical OCT2 substrate. The inhibitory effect of atenolol on MPP+ transport was 6200-fold lower than that observed for MPP+ on atenolol transport. Additionally, we observed weaker inhibitory effects on MPP+ transport compared to atenolol transport with ten different OCT2 substrates. Altogether, this study suggests that eight hOCT2-specific amino acids constitute the low-affinity recognition site for atenolol transport, indicating differences in OCT2-mediated drug elimination between humans and highly homologous monkeys. Our findings underscore the importance of understanding species-specific differences in drug transport mechanisms, shedding light on potential variations in drug disposition and aiding in drug development.
Collapse
Affiliation(s)
- Akira Hosooka
- Graduate School of Pharmaceutical Sciences, Nagoya City University, 3-1 Tanabe-dori, Mizuho-ku, Nagoya 467-8603, Japan
| | - Tomoya Yasujima
- Graduate School of Pharmaceutical Sciences, Nagoya City University, 3-1 Tanabe-dori, Mizuho-ku, Nagoya 467-8603, Japan.
| | - Ayano Murata
- Graduate School of Pharmaceutical Sciences, Nagoya City University, 3-1 Tanabe-dori, Mizuho-ku, Nagoya 467-8603, Japan
| | - Takahiro Yamashiro
- Graduate School of Pharmaceutical Sciences, Nagoya City University, 3-1 Tanabe-dori, Mizuho-ku, Nagoya 467-8603, Japan
| | - Hiroaki Yuasa
- Graduate School of Pharmaceutical Sciences, Nagoya City University, 3-1 Tanabe-dori, Mizuho-ku, Nagoya 467-8603, Japan
| |
Collapse
|
2
|
Pernecker M, Ciarimboli G. Regulation of renal organic cation transporters. FEBS Lett 2024. [PMID: 38831380 DOI: 10.1002/1873-3468.14943] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2024] [Revised: 04/30/2024] [Accepted: 05/21/2024] [Indexed: 06/05/2024]
Abstract
Transporters for organic cations (OCs) facilitate exchange of positively charged molecules through the plasma membrane. Substrates for these transporters encompass neurotransmitters, metabolic byproducts, drugs, and xenobiotics. Consequently, these transporters actively contribute to the regulation of neurotransmission, cellular penetration and elimination process for metabolic products, drugs, and xenobiotics. Therefore, these transporters have significant physiological, pharmacological, and toxicological implications. In cells of renal proximal tubules, the vectorial secretion pathways for OCs involve expression of organic cation transporters (OCTs) and multidrug and toxin extrusion proteins (MATEs) on basolateral and apical membrane domains, respectively. This review provides an overview of documented regulatory mechanisms governing OCTs and MATEs. Additionally, regulation of these transporters under various pathological conditions is summarized. The expression and functionality of OCTs and MATEs are subject to diverse pre- and post-translational modifications, providing insights into their regulation in various pathological conditions. Typically, in diseases, downregulation of transporter expression is observed, probably as a protective mechanism to prevent additional damage to kidney tissue. This regulation may be attributed to the intricate network of modifications these transporters undergo, shedding light on their dynamic responses in pathological contexts.
Collapse
Affiliation(s)
- Moritz Pernecker
- Experimental Nephrology, Department of Internal Medicine D, University Hospital Münster, Germany
| | - Giuliano Ciarimboli
- Experimental Nephrology, Department of Internal Medicine D, University Hospital Münster, Germany
| |
Collapse
|
3
|
Thévenod F, Lee WK. Cadmium transport by mammalian ATP-binding cassette transporters. Biometals 2024; 37:697-719. [PMID: 38319451 PMCID: PMC11101381 DOI: 10.1007/s10534-024-00582-5] [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: 09/15/2023] [Accepted: 01/04/2024] [Indexed: 02/07/2024]
Abstract
Cellular responses to toxic metals depend on metal accessibility to intracellular targets, reaching interaction sites, and the intracellular metal concentration, which is mainly determined by uptake pathways, binding/sequestration and efflux pathways. ATP-binding cassette (ABC) transporters are ubiquitous in the human body-usually in epithelia-and are responsible for the transfer of indispensable physiological substrates (e.g. lipids and heme), protection against potentially toxic substances, maintenance of fluid composition, and excretion of metabolic waste products. Derailed regulation and gene variants of ABC transporters culminate in a wide array of pathophysiological disease states, such as oncogenic multidrug resistance or cystic fibrosis. Cadmium (Cd) has no known physiological role in mammalians and poses a health risk due to its release into the environment as a result of industrial activities, and eventually passes into the food chain. Epithelial cells, especially within the liver, lungs, gastrointestinal tract and kidneys, are particularly susceptible to the multifaceted effects of Cd because of the plethora of uptake pathways available. Pertinent to their broad substrate spectra, ABC transporters represent a major cellular efflux pathway for Cd and Cd complexes. In this review, we summarize current knowledge concerning transport of Cd and its complexes (mainly Cd bound to glutathione) by the ABC transporters ABCB1 (P-glycoprotein, MDR1), ABCB6, ABCC1 (multidrug resistance related protein 1, MRP1), ABCC7 (cystic fibrosis transmembrane regulator, CFTR), and ABCG2 (breast cancer related protein, BCRP). Potential detoxification strategies underlying ABC transporter-mediated efflux of Cd and Cd complexes are discussed.
Collapse
Affiliation(s)
- Frank Thévenod
- Institute for Physiology, Pathophysiology and Toxicology & ZBAF, Witten/Herdecke University, 58453, Witten, Germany
- Physiology and Pathophysiology of Cells and Membranes, Medical School OWL, Bielefeld University, Morgenbreede 1, 33615, Bielefeld, Germany
| | - Wing-Kee Lee
- Physiology and Pathophysiology of Cells and Membranes, Medical School OWL, Bielefeld University, Morgenbreede 1, 33615, Bielefeld, Germany.
| |
Collapse
|
4
|
Chen Y, Lu S, Zhang Y, Chen B, Zhou H, Jiang H. Examination of the emerging role of transporters in the assessment of nephrotoxicity. Expert Opin Drug Metab Toxicol 2022; 18:787-804. [PMID: 36420583 DOI: 10.1080/17425255.2022.2151892] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
INTRODUCTION The kidney is vulnerable to various injuries based on its function in the elimination of many xenobiotics, endogenous substances and metabolites. Since transporters are critical for the renal elimination of those substances, it is urgent to understand the emerging role of transporters in nephrotoxicity. AREAS COVERED This review summarizes the contribution of major renal transporters to nephrotoxicity induced by some drugs or toxins; addresses the role of transporter-mediated endogenous metabolic disturbances in nephrotoxicity; and discusses the advantages and disadvantages of in vitro models based on transporter expression and function. EXPERT OPINION Due to the crucial role of transporters in the renal disposition of xenobiotics and endogenous substances, it is necessary to further elucidate their renal transport mechanisms and pay more attention to the underlying relationship between the transport of endogenous substances and nephrotoxicity. Considering the species differences in the expression and function of transporters, and the low expression of transporters in general cell models, in vitro humanized models, such as humanized 3D organoids, shows significant promise in nephrotoxicity prediction and mechanism study.
Collapse
Affiliation(s)
- Yujia Chen
- Institute of Drug Metabolism and Pharmaceutical Analysis, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou, P.R. China
| | - Shuanghui Lu
- Institute of Drug Metabolism and Pharmaceutical Analysis, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou, P.R. China
| | - Yingqiong Zhang
- Institute of Drug Metabolism and Pharmaceutical Analysis, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou, P.R. China.,Affiliated Hangzhou First People's Hospital, Zhejiang University School of Medicine, Hangzhou, P.R. China
| | - Binxin Chen
- Institute of Drug Metabolism and Pharmaceutical Analysis, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou, P.R. China
| | - Hui Zhou
- Institute of Drug Metabolism and Pharmaceutical Analysis, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou, P.R. China.,Jinhua Institute of Zhejiang University, Jinhua, P.R. China
| | - Huidi Jiang
- Institute of Drug Metabolism and Pharmaceutical Analysis, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou, P.R. China.,Jinhua Institute of Zhejiang University, Jinhua, P.R. China
| |
Collapse
|
5
|
Hafey MJ, Aleksunes LM, Bridges CC, Brouwer KR, Chien HC, Leslie EM, Hu S, Li Y, Shen J, Sparreboom A, Sprowl J, Tweedie D, Lai Y. Transporters and Toxicity: Insights from the International Transporter Consortium Workshop 4. Clin Pharmacol Ther 2022; 112:527-539. [PMID: 35546260 DOI: 10.1002/cpt.2638] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2022] [Accepted: 04/30/2022] [Indexed: 12/29/2022]
Abstract
Over the last decade, significant progress been made in elucidating the role of membrane transporters in altering drug disposition, with important toxicological consequences due to changes in localized concentrations of compounds. The topic of "Transporters and Toxicity" was recently highlighted as a scientific session at the International Transporter Consortium (ITC) Workshop 4 in 2021. The current white paper is not intended to be an extensive review on the topic of transporters and toxicity but an opportunity to highlight aspects of the role of transporters in various toxicities with clinically relevant implications as covered during the session. This includes a review of the role of solute carrier transporters in anticancer drug-induced organ injury, transporters as key players in organ barrier function, and the role of transporters in metal/metalloid toxicity.
Collapse
Affiliation(s)
- Michael J Hafey
- ADME and Discovery Toxicology, Merck & Co., Inc., Rahway, New Jersey, USA
| | - Lauren M Aleksunes
- Department of Pharmacology and Toxicology, Rutgers University, Piscataway, New Jersey, USA
| | - Christy C Bridges
- Department of Biomedical Sciences, Mercer University School of Medicine, Macon, Georgia, USA
| | | | - Huan-Chieh Chien
- Pharmacokinetics and Drug Metabolism, Amgen, Inc., South San Francisco, California, USA
| | - Elaine M Leslie
- Departments of Physiology and Lab Med and Path, Membrane Protein Disease Research Group, University of Alberta, Edmonton, Alberta, Canada
| | - Shuiying Hu
- Division of Outcomes and Translational Sciences, College of Pharmacy, The Ohio State University, Columbus, Ohio, USA
| | - Yang Li
- Division of Pharmaceutics and Pharmacology, College of Pharmacy, The Ohio State University, Columbus, Ohio, USA
| | - Jinshan Shen
- Relay Therapeutics, Cambridge, Massachusetts, USA
| | - Alex Sparreboom
- Division of Pharmaceutics and Pharmacology, College of Pharmacy, The Ohio State University, Columbus, Ohio, USA
| | - Jason Sprowl
- Department of Pharmaceutical Sciences, School of Pharmacy and Pharmaceutical Sciences, University at Buffalo, Buffalo, New York, USA
| | | | - Yurong Lai
- Drug Metabolism, Gilead Sciences Inc., Foster City, California, USA
| |
Collapse
|
6
|
The role of cholesterol recognition (CARC/CRAC) mirror codes in the allosterism of the human organic cation transporter 2 (OCT2, SLC22A2). Biochem Pharmacol 2021; 194:114840. [PMID: 34774844 DOI: 10.1016/j.bcp.2021.114840] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2021] [Revised: 11/08/2021] [Accepted: 11/09/2021] [Indexed: 11/21/2022]
Abstract
The human organic cation transporter 2 (OCT2) is a multispecific transporter with cholesterol-dependent allosteric features. The present work elucidates the role of evolutionarily conserved cholesterol recognition/interaction amino acid consensus sequences (CRAC and CARC) in the allosteric binding to 1-methyl-4-phenylpyridinium (MPP+) in human embryonic kidney 293 cells stably or transiently expressing OCT2. Molecular blind simulations docked two mirroring cholesterol molecules in the 5th putative transmembrane domain, where a CARC and a CRAC sequence lie. The impact of the conserved amino acids that may constitute the CARC/CRAC mirror code was studied by alanine-scanning mutagenesis. At a saturating extracellular concentration of substrate, at which the impact of cholesterol depletion is maximal, five mutants transported MPP+ at a significantly lower rate than the wild-type OCT2 (WT), resembling the behavior of the WT upon cholesterol depletion. MPP+ influx rate as a function of the extracellular concentration of substrate was measured for the mutants R234A, R235A, L252A and R263A. R234A kinetic behavior was similar to that of the WT, whereas R235A, L252A and R263A activity shifted from allosteric to one-binding site kinetics, very much like the WT upon cholesterol depletion. The impact of cholesterol on protein thermal stability was assessed for WT, R234A and R263A. While the thermal stability of WT and R234A was improved by the supplementation with cholesterol, R263A was not sensitive to the presence of cholesterol. To conclude, the disruption of the CARC/CRAC mirror code in the 5th putative transmembrane domain is sufficient to abolish the allosteric interaction between OCT2 and MPP+.
Collapse
|
7
|
Koepsell H. Update on drug-drug interaction at organic cation transporters: mechanisms, clinical impact, and proposal for advanced in vitro testing. Expert Opin Drug Metab Toxicol 2021; 17:635-653. [PMID: 33896325 DOI: 10.1080/17425255.2021.1915284] [Citation(s) in RCA: 35] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Introduction: Organic cation transporters collectively called OCTs belong to three gene families (SLC22A1 OCT1, SLC22A2 OCT2, SLC22A3 OCT3, SLC22A4 OCTN1, SLC22A5 OCTN2, SLC29A4 PMAT, SLC47A1 MATE1, and SLC47A1 MATE2-K). OCTs transport structurally diverse drugs with overlapping selectivity. Some OCTs were shown to be critically involved in pharmacokinetics and therapeutic efficacy of cationic drugs. Drug-drug interactions at individual OCTs were shown to result in clinical effects. Procedures for in vitro testing of drugs for interaction with OCT1, OCT2, MATE1, and MATE2-K have been recommended.Areas covered: An overview of functional properties, cation selectivity, location, and clinical impact of OCTs is provided. In addition, clinically relevant drug-drug interactions in OCTs are compiled. Because it was observed that the half maximal concentration of drugs to inhibit transport by OCTs (IC50) is dependent on the transported cation and its concentration, an advanced protocol for in vitro testing of drugs for interaction with OCTs is proposed. In addition, it is suggested to include OCT3 and PMAT for in vitro testing.Expert opinion: Research on clinical roles of OCTs should be reinforced including more transporters and drugs. An improvement of the in vitro testing protocol considering recent data is imperative for the benefit of patients.
Collapse
Affiliation(s)
- Hermann Koepsell
- Institute of Anatomy and Cell Biology, University Würzburg, Würzburg, Germany
| |
Collapse
|
8
|
Zhang Y, Sun M, Jian S, Huang J, Xiao C, Zhang X, Hu R, Si L. mPEG 2k-PCL x Polymeric Micelles Influence Pharmacokinetics and Hypoglycemic Efficacy of Metformin through Inhibition of Organic Cation Transporters in Rats. Mol Pharm 2021; 18:2586-2599. [PMID: 34102842 DOI: 10.1021/acs.molpharmaceut.1c00078] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Increasing evidence has shown that nanocarriers have effects on several efflux drug transporters. To date, little is known about whether influx transporters are also modulated. Herein, we investigated the impact of amphiphilic polymer micelles on the uptake function of organic cation transporters (OCTs) and the influence on the pharmacokinetics and pharmacodynamics of metformin, a well-characterized substrate of OCTs. Five types of polymeric micelles (mPEG2k-PCL2k, mPEG2k-PCL3.5k, mPEG2k-PCL5k, mPEG2k-PCL7.5k, and mPEG2k-PCL10k) were prepared to evaluate the inhibition of hOCT1-3-overexpressing Madin-Darby canine kidney cells. The mPEG2k-PCLx micelles played an inhibitory role above the critical micelle concentration. The inhibitory potency could be ranked as mPEG2k-PCL2k > mPEG2k-PCL3.5k > mPEG2k-PCL5k > mPEG2k-PCL7.5k > mPEG2k-PCL10k, which negatively declined with the increase of molecular weight of the hydrophobic segment. The inhibitory effects of polymeric micelles on the hOCT1 isoform were the most pronounced, with the lowest IC50 values ranging from 0.106 to 0.280 mg/mL. The mPEG2k-PCL2k micelles distinctly increased the plasma concentration of metformin and significantly decreased Vss by 35.6% (p < 0.05) after seven consecutive treatments in rats, which was interrelated with the restrained metformin distribution in the liver and kidney. The uptake inhibition of micelles on hepatic and renal rOcts also diminished the glucose-lowering effect of metformin and fasting insulin levels in the oral glucose tolerance test. Consistent with the inhibitory effects, the mRNA and protein levels of rOct1 and rOct2 were decreased in the liver, kidney, and small intestine. The present study demonstrated that mPEG2k-PCLx micelles could inhibit the transport function of OCTs, indicating a potential risk of drug-drug interactions during concomitant medication of nanomedicine with organic cationic drugs.
Collapse
Affiliation(s)
- Ying Zhang
- Department of Pharmaceutics, School of Pharmacy, Tongji Medical College of Huazhong University of Science and Technology, Hangkong Road 13, Wuhan 430030, PR China
| | - Minghui Sun
- Department of Pharmaceutics, Affiliated Tongji Hospital, Tongji Medical College of Huazhong University of Science and Technology, Jiefang Avenue 1095, Wuhan 430030, PR China
| | - Shuxin Jian
- Department of Pharmaceutics, School of Pharmacy, Tongji Medical College of Huazhong University of Science and Technology, Hangkong Road 13, Wuhan 430030, PR China
| | - Jiangeng Huang
- Department of Pharmaceutics, School of Pharmacy, Tongji Medical College of Huazhong University of Science and Technology, Hangkong Road 13, Wuhan 430030, PR China
| | - Chuyao Xiao
- Department of Pharmaceutics, School of Pharmacy, Tongji Medical College of Huazhong University of Science and Technology, Hangkong Road 13, Wuhan 430030, PR China
| | - Xiangyu Zhang
- Department of Pharmaceutics, School of Pharmacy, Tongji Medical College of Huazhong University of Science and Technology, Hangkong Road 13, Wuhan 430030, PR China
| | - Ruhao Hu
- Department of Pharmaceutics, School of Pharmacy, Tongji Medical College of Huazhong University of Science and Technology, Hangkong Road 13, Wuhan 430030, PR China
| | - Luqin Si
- Department of Pharmaceutics, School of Pharmacy, Tongji Medical College of Huazhong University of Science and Technology, Hangkong Road 13, Wuhan 430030, PR China
| |
Collapse
|
9
|
Divergent Regulation of OCT and MATE Drug Transporters by Cadmium Exposure. Pharmaceutics 2021; 13:pharmaceutics13040537. [PMID: 33924306 PMCID: PMC8069296 DOI: 10.3390/pharmaceutics13040537] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2021] [Revised: 03/26/2021] [Accepted: 04/08/2021] [Indexed: 12/18/2022] Open
Abstract
Coordinated transcellular transport by the uptake via organic cation transporters (OCTs) in concert with the efflux via multidrug and toxin extrusion proteins (MATEs) is an essential system for hepatic and renal drug disposition. Despite their clinical importance, the regulation of OCTs and MATEs remains poorly characterized. It has been reported that cadmium (Cd2+) increase the activities of OCTs while being a substrate of MATEs. Here, we found that human (h) OCT2 protein, as compared with hMATE1, was more active in trafficking between the plasma membrane and cytoplasmic storage pool. Cd2+ exposure could significantly enhance the translocation of hOCT2 and hOCT1, but not hMATE1, to the plasma membrane. We further identified that candesartan, a widely prescribed angiotensin II receptor blocker, behaved similarly toward OCT2 and MATE1 as Cd2+ did. Importantly, Cd2+ and candesartan treatments could lead to an enhanced accumulation of metformin, which is a well-characterized substrate of OCTs/MATEs, in mouse kidney and liver, respectively. Altogether, our studies have uncovered possible divergent regulation of OCTs and MATEs by certain xenobiotics, such as Cd2+ and candesartan due to the different cellular trafficking of these two families of transporter proteins, which might significantly affect drug disposition in the liver and kidney.
Collapse
|
10
|
Substrates and Inhibitors of Organic Cation Transporters (OCTs) and Plasma Membrane Monoamine Transporter (PMAT) and Therapeutic Implications. Handb Exp Pharmacol 2021; 266:119-167. [PMID: 34495395 DOI: 10.1007/164_2021_516] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The gene products of the SLC22A gene family (hOCT1, hOCT2, and hOCT3) and of the SLC29A4 gene (hPMAT or hENT4) are all polyspecific organic cation transporters. Human OCTs (including hPMAT) are expressed in peripheral tissues such as small intestine, liver, and kidney involved in the pharmacokinetics of drugs. In the human brain, all four transporters are expressed at the blood-brain barrier (BBB), hOCT2 is additionally expressed in neurons, and hOCT3 and hPMAT in glia. More than 40% of the presently used drugs are organic cations. This chapter lists and discusses all known drugs acting as substrates or inhibitors of these four organic cation transporters, independently of whether the transporter is expressed in the central nervous system (CNS) or in peripheral tissues. Of interest is their involvement in drug absorption, distribution, and excretion as well as potential OCT-associated drug-drug interactions (DDIs), with a focus on drugs that act in the CNS.
Collapse
|
11
|
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.
Collapse
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
| |
Collapse
|
12
|
Hernández Lozano I, Bauer M, Wulkersdorfer B, Traxl A, Philippe C, Weber M, Häusler S, Stieger B, Jäger W, Mairinger S, Wanek T, Hacker M, Zeitlinger M, Langer O. Measurement of Hepatic ABCB1 and ABCG2 Transport Activity with [ 11C]Tariquidar and PET in Humans and Mice. Mol Pharm 2019; 17:316-326. [PMID: 31790256 DOI: 10.1021/acs.molpharmaceut.9b01060] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
P-Glycoprotein (ABCB1) and breast cancer resistance protein (ABCG2) in the canalicular membrane of hepatocytes mediate the biliary excretion of drugs and drug metabolites. To measure hepatic ABCB1 and ABCG2 activity, we performed positron emission tomography (PET) scans with the ABCB1/ABCG2 substrate [11C]tariquidar in healthy volunteers and wild-type, Abcb1a/b(-/-), Abcg2(-/-), and Abcb1a/b(-/-)Abcg2(-/-) mice without and with coadministration of unlabeled tariquidar. PET data were analyzed with a three-compartment pharmacokinetic model. [11C]Tariquidar underwent hepatobiliary excretion in both humans and mice, and tariquidar coadministration caused a significant reduction in the rate constant for the transfer of radioactivity from the liver into bile (by -74% in humans and by -62% in wild-type mice), suggesting inhibition of canalicular efflux transporter activity. Radio-thin-layer chromatography analysis revealed that the majority of radioactivity (>87%) in the mouse liver and bile was composed of unmetabolized [11C]tariquidar. PET data in transporter knockout mice revealed that both ABCB1 and ABCG2 mediated biliary excretion of [11C]tariquidar. In vitro experiments indicated that tariquidar is not a substrate of major hepatic basolateral uptake transporters (SLCO1B1, SLCO1B3, SLCO2B1, SLC22A1, and SLC22A3). Our data suggest that [11C]tariquidar can be used to measure hepatic canalicular ABCB1/ABCG2 transport activity without a confounding effect of uptake transporters.
Collapse
Affiliation(s)
- Irene Hernández Lozano
- Department of Clinical Pharmacology , Medical University of Vienna , Vienna 1090 , Austria
| | - Martin Bauer
- Department of Clinical Pharmacology , Medical University of Vienna , Vienna 1090 , Austria
| | - Beatrix Wulkersdorfer
- Department of Clinical Pharmacology , Medical University of Vienna , Vienna 1090 , Austria
| | - Alexander Traxl
- Preclinical Molecular Imaging , AIT Austrian Institute of Technology GmbH , Seibersdorf 2444 , Austria
| | - Cécile Philippe
- Division of Nuclear Medicine, Department of Biomedical Imaging and Image-Guided Therapy , Medical University of Vienna , Vienna 1090 , Austria
| | - Maria Weber
- Department of Clinical Pharmacology , Medical University of Vienna , Vienna 1090 , Austria
| | - Stephanie Häusler
- Department of Clinical Pharmacology and Toxicology , University Hospital Zurich, University of Zurich , Zurich 8006 , Switzerland
| | - Bruno Stieger
- Department of Clinical Pharmacology and Toxicology , University Hospital Zurich, University of Zurich , Zurich 8006 , Switzerland
| | - Walter Jäger
- Department of Clinical Pharmacy and Diagnostics , University of Vienna , Vienna 1090 , Austria
| | - Severin Mairinger
- Preclinical Molecular Imaging , AIT Austrian Institute of Technology GmbH , Seibersdorf 2444 , Austria
| | - Thomas Wanek
- Preclinical Molecular Imaging , AIT Austrian Institute of Technology GmbH , Seibersdorf 2444 , Austria
| | - Marcus Hacker
- Division of Nuclear Medicine, Department of Biomedical Imaging and Image-Guided Therapy , Medical University of Vienna , Vienna 1090 , Austria
| | - Markus Zeitlinger
- Department of Clinical Pharmacology , Medical University of Vienna , Vienna 1090 , Austria
| | - Oliver Langer
- Department of Clinical Pharmacology , Medical University of Vienna , Vienna 1090 , Austria.,Preclinical Molecular Imaging , AIT Austrian Institute of Technology GmbH , Seibersdorf 2444 , Austria.,Division of Nuclear Medicine, Department of Biomedical Imaging and Image-Guided Therapy , Medical University of Vienna , Vienna 1090 , Austria
| |
Collapse
|
13
|
Yang H, Tang J, Guo D, Zhao Q, Wen J, Zhang Y, Obianom ON, Zhou S, Zhang W, Shu Y. Cadmium exposure enhances organic cation transporter 2 trafficking to the kidney membrane and exacerbates cisplatin nephrotoxicity. Kidney Int 2019; 97:765-777. [PMID: 32061436 DOI: 10.1016/j.kint.2019.11.012] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2019] [Revised: 10/01/2019] [Accepted: 11/01/2019] [Indexed: 12/17/2022]
Abstract
Renal accumulation and exposure of cadmium originating from pollution in agricultural land and the prevalence of cigarette smoking remains an unneglectable human health concern. Whereas cadmium exposure has been correlated with increased incidence of a variety of kidney diseases, little is known pertaining to its effect on renal drug disposition and response in patients. Here, we report that cadmium exposure significantly increased the activity of organic cation transporter 2 (OCT2), a critical renal drug transporter recommended in United States Federal Drug Administration guidance for assessment during drug development. Cadmium enhanced OCT2 trafficking to the cell membrane both in vitro and in vivo. Mechanistically cadmium-mediated OCT2 translocation was found to involve protein-protein interaction between serine/threonine-protein kinase AKT2, calcium/calmodulin and the AKT substrate AS160 in in vitro cellular studies. The formed protein complex could selectively facilitate phosphorylation of AKT2 at T309, which induced translocation of OCT2 to the plasma membrane. Moreover, cadmium exposure markedly exacerbated nephrotoxicity induced by cisplatin, an OCT2 substrate, by increasing its accumulation in the mouse kidney. Consistently, there was a significant correlation between plasma cadmium level and alteration of renal function in cervical cancer patients who underwent chemotherapy with cisplatin. Thus, our studies suggest that membrane transporter distribution induced by cadmium exposure is a previously unrecognized factor for the broad variation in renal drug disposition and response.
Collapse
Affiliation(s)
- Hong Yang
- Department of Pharmaceutical Sciences, School of Pharmacy, University of Maryland at Baltimore, Baltimore, Maryland, USA
| | - Jie Tang
- Department of Clinical Pharmacology, Xiangya Hospital, Central South University, Hunan, China
| | - Dong Guo
- Department of Pharmaceutical Sciences, School of Pharmacy, University of Maryland at Baltimore, Baltimore, Maryland, USA
| | - Qingqing Zhao
- Department of Clinical Pharmacology, Xiangya Hospital, Central South University, Hunan, China
| | - Jiagen Wen
- Department of Clinical Pharmacology, Xiangya Hospital, Central South University, Hunan, China
| | - Yanjuan Zhang
- Department of Clinical Pharmacology, Xiangya Hospital, Central South University, Hunan, China
| | - Obinna N Obianom
- Department of Pharmaceutical Sciences, School of Pharmacy, University of Maryland at Baltimore, Baltimore, Maryland, USA
| | - Shiwei Zhou
- Department of Pharmaceutical Sciences, School of Pharmacy, University of Maryland at Baltimore, Baltimore, Maryland, USA
| | - Wei Zhang
- Department of Clinical Pharmacology, Xiangya Hospital, Central South University, Hunan, China
| | - Yan Shu
- Department of Pharmaceutical Sciences, School of Pharmacy, University of Maryland at Baltimore, Baltimore, Maryland, USA.
| |
Collapse
|
14
|
Wright SH. Molecular and cellular physiology of organic cation transporter 2. Am J Physiol Renal Physiol 2019; 317:F1669-F1679. [PMID: 31682169 DOI: 10.1152/ajprenal.00422.2019] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Organic cation transporters play a critical role in mediating the distribution of cationic pharmaceuticals. Indeed, organic cation transporter (OCT)2 is the initial step in the renal secretion of organic cations and consequently plays a defining role in establishing the pharmacokinetics of many cationic drugs. Although a hallmark of OCTs is their broad selectivity, this characteristic also makes them targets for unwanted, adverse drug-drug interactions (DDIs), making them a focus for efforts to develop models of ligand interaction that could predict and preempt these adverse interactions. This review discusses the molecular characteristics of these transporters as well as the evidence that established the OCTs as key players in the distribution of organic cations. However, the primary focus is the present understanding of the complexity of ligand interaction with OCTs, particularly OCT2, including evidence for the presence of multiple ligand-binding sites and the influence of substrate structure on the affinity of the transporter for inhibitory ligands. This leads to a discussion of the complexities associated with the development of protocols for assessing the inhibitory potential of new molecular entities to perpetrate unwanted DDIs, the criteria that should be considered in the interpretation of the results of such protocols, and the challenges associated with development of models capable of predicting unwanted DDIs.
Collapse
Affiliation(s)
- Stephen H Wright
- Department of Physiology, University of Arizona, Tucson, Arizona
| |
Collapse
|
15
|
Hörmann S, Gai Z, Kullak-Ublick GA, Visentin M. Plasma Membrane Cholesterol Regulates the Allosteric Binding of 1-Methyl-4-Phenylpyridinium to Organic Cation Transporter 2 (SLC22A2). J Pharmacol Exp Ther 2019; 372:46-53. [DOI: 10.1124/jpet.119.260877] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2019] [Accepted: 10/11/2019] [Indexed: 12/27/2022] Open
|
16
|
Frenzel D, Köppen C, Bolle Bauer O, Karst U, Schröter R, Tzvetkov MV, Ciarimboli G. Effects of Single Nucleotide Polymorphism Ala270Ser (rs316019) on the Function and Regulation of hOCT2. Biomolecules 2019; 9:E578. [PMID: 31591331 PMCID: PMC6843571 DOI: 10.3390/biom9100578] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2019] [Revised: 09/30/2019] [Accepted: 10/03/2019] [Indexed: 12/21/2022] Open
Abstract
The human organic cation transporter 2 (hOCT2) is highly expressed in proximal tubules of the kidneys, where it plays an important role in the secretion of organic cations. Since many drugs are organic cations, hOCT2 has relevant pharmacological implications. The hOCT2 gene is polymorphic, and the nonsynonymous single nucleotide polymorphism (SNP) causing the substitution of alanine at position 270 of the protein sequence with serine (Ala270Ser) is present with high frequency in the human population. Therefore, Ala270Ser has potentially important pharmacologic consequences. Here, we analyzed the transport properties and rapid regulation of hOCT2 wildtype and hOCT2 Ala270Ser expressed in human embryonic kidney cells using real-time uptake measurements. Moreover, we compared the expression of hOCT2 in the plasma membrane determined by biotinylation experiments and the cellular transport and toxicity of cisplatin measured by inductively coupled plasma mass spectrometry and a viability test, respectively. The transport characteristics and regulation of the wildtype and mutated hOCT2 were very similar. Interestingly, a higher affinity of hOCT2 Ala270Ser for creatinine was observed. Compared with hOCT2 wildtype, the plasma membrane expression, cisplatin transport, and cisplatin-associated toxicity of hOCT2 Ala270Ser were significantly lower. In conclusion, these findings suggest that Ala270Ser has subtle but important effects on hOCT2 function, which are probably difficult to detect in studies with patients.
Collapse
Affiliation(s)
- Dominik Frenzel
- Medizinische Klinik D, Experimentelle Nephrologie, Universitätsklinikum Münster, 48149 Münster, Germany; (D.F.); (R.S.)
| | - Christina Köppen
- Institut für Anorganische und Analytische Chemie, Westfälische Wilhelms-Universität, 48149 Münster, Germany; (C.K.); (O.B.B.); (U.K.)
| | - Oliver Bolle Bauer
- Institut für Anorganische und Analytische Chemie, Westfälische Wilhelms-Universität, 48149 Münster, Germany; (C.K.); (O.B.B.); (U.K.)
| | - Uwe Karst
- Institut für Anorganische und Analytische Chemie, Westfälische Wilhelms-Universität, 48149 Münster, Germany; (C.K.); (O.B.B.); (U.K.)
| | - Rita Schröter
- Medizinische Klinik D, Experimentelle Nephrologie, Universitätsklinikum Münster, 48149 Münster, Germany; (D.F.); (R.S.)
| | - Mladen V. Tzvetkov
- Institut für Pharmakologie, Abteilung Klinische Pharmakologie, Universitätsmedizin Greifswald, 17487 Greifswald, Germany;
| | - Giuliano Ciarimboli
- Medizinische Klinik D, Experimentelle Nephrologie, Universitätsklinikum Münster, 48149 Münster, Germany; (D.F.); (R.S.)
| |
Collapse
|
17
|
Koepsell H. Multiple binding sites in organic cation transporters require sophisticated procedures to identify interactions of novel drugs. Biol Chem 2019; 400:195-207. [PMID: 30138103 DOI: 10.1515/hsz-2018-0191] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2018] [Accepted: 08/08/2018] [Indexed: 01/09/2023]
Abstract
In vitro evaluation of drugs for interaction with transporters is essential during drug development. As polyspecific organic cation transporters (OCTs) are critical for pharmacokinetics of many cationic drugs, in vitro testing of human OCT1 and human OCT2 is recommended. In the currently applied tests it is determined whether uptake of one model cation in stably transfected epithelial cells is inhibited using a substrate concentration in the micromolar range. In this review experimental evidence for the existence of low- and high-affinity cation binding sites in OCTs that may interact with drugs is compiled. Most data were obtained from studies performed with rat Oct1. Whereas overlapping low-affinity cation binding sites are directly involved in transport, the high-affinity cation binding sites may induce allosteric inhibition of transport. Remarkably, high-affinity inhibition is only observed when uptake is measured using nanomolar substrate concentrations far below the respective Km values. Affinities of inhibitors are dependent on molecular structure and concentration of the employed substrate. Because the currently applied in vitro tests for identification of interaction of novel drugs with OCTs do not consider the influence of substrate structure and are not capable of identifying high-affinity inhibition, more sophisticated testing protocols are proposed.
Collapse
Affiliation(s)
- Hermann Koepsell
- Institute of Anatomy and Cell Biology, University of Würzburg, Koellikerstr. 6, D-97070 Würzburg, Germany.,Department of Molecular Plant Physiology and Biophysics, Julius von Sachs Institute, University of Würzburg, D-97082 Würzburg, Germany
| |
Collapse
|
18
|
Sandoval PJ, Morales M, Secomb TW, Wright SH. Kinetic basis of metformin-MPP interactions with organic cation transporter OCT2. Am J Physiol Renal Physiol 2019; 317:F720-F734. [PMID: 31313952 DOI: 10.1152/ajprenal.00152.2019] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Organic cation transporter 2 (OCT2) clears the blood of cationic drugs. Efforts to understand OCT2 selectivity as a means to predict the potential of new molecular entities (NMEs) to produce unwanted drug-drug interactions typically assess the influence of the NMEs on inhibition of transport. However, the identity of the substrate used to assess transport activity can influence the quantitative profile of inhibition. Metformin and 1-methyl-4-phenylpyridinium (MPP), in particular, display markedly different inhibitory profiles, with IC50 values for inhibition of MPP transport often being more than fivefold greater than IC50 values for the inhibition of metformin transport by the same compound, suggesting that interaction of metformin and MPP with OCT2 cannot be restricted to competition for a single binding site. Here, we determined the kinetic basis for the mutual inhibitory interaction of metformin and MPP with OCT2 expressed in Chinese hamster ovary cells. Although metformin did produce simple competitive inhibition of MPP transport, MPP was a mixed-type inhibitor of metformin transport, decreasing the maximum rate of mediated substrate transport and increasing the apparent Michaelis constant (Ktapp) for OCT2-mediated metformin transport. Furthermore, whereas the IC50 value for metformin's inhibition of MPP transport did not differ from the Ktapp value for metformin transport, the IC50 value for MPP's inhibition of metformin transport was less than its Ktapp value for transport. The simplest model to account for these observations required the influence of a distinct inhibitory site for MPP that, when occupied, decreases the translocation of substrate. These observations underscore the complexity of ligand interaction with OCT2 and argue for use of multiple substrates to obtain the needed kinetic assessment of NME interactions with OCT2.
Collapse
Affiliation(s)
| | - Mark Morales
- Department of Physiology, University of Arizona, Tucson, Arizona
| | - Timothy W Secomb
- Department of Physiology, University of Arizona, Tucson, Arizona
| | - Stephen H Wright
- Department of Physiology, University of Arizona, Tucson, Arizona
| |
Collapse
|
19
|
Channels, transporters and receptors for cadmium and cadmium complexes in eukaryotic cells: myths and facts. Biometals 2019; 32:469-489. [DOI: 10.1007/s10534-019-00176-6] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2019] [Accepted: 01/21/2019] [Indexed: 12/21/2022]
|
20
|
Minuesa G, Albert C, Pastor-Anglada M, Martinez-Picado J, Koepsell H. Response to "Tenofovir Disoproxil Fumarate Is Not an Inhibitor of Human Organic Cation Transporter 1". J Pharmacol Exp Ther 2018; 360:343-345. [PMID: 28104832 DOI: 10.1124/jpet.116.239004] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2016] [Accepted: 11/11/2016] [Indexed: 12/12/2022] Open
Affiliation(s)
- Gerard Minuesa
- IrsiCaixa Foundation, Hospital Germans Trias i Pujol, Universitat Autònoma de Barcelona, Badalona, Spain (G.M., J.M.-P.); Institute of Anatomy and Cell Biology, University of Würzburg, Würzburg, Germany (C.A., H.K.); Departament de Bioquímica i Biomedicina Molecular, Facultat de Biologia, Institut de Biomedicina, Universitat de Barcelona (IBUB) and Centro de Investigación Biomédica en Red-Enfermedades Hepáticas y Digestivas (CIBER EHD), Barcelona, Spain (M.P.-A.); Institució Catalana de Recerca i Estudis Avançats, Barcelona, Spain (J.M.-P.); Department of Molecular Plant Physiology and Biophysics, Julius-von-Sachs-Institute, University of Würzburg, Würzburg, Germany (H.K.)
| | - Christopher Albert
- IrsiCaixa Foundation, Hospital Germans Trias i Pujol, Universitat Autònoma de Barcelona, Badalona, Spain (G.M., J.M.-P.); Institute of Anatomy and Cell Biology, University of Würzburg, Würzburg, Germany (C.A., H.K.); Departament de Bioquímica i Biomedicina Molecular, Facultat de Biologia, Institut de Biomedicina, Universitat de Barcelona (IBUB) and Centro de Investigación Biomédica en Red-Enfermedades Hepáticas y Digestivas (CIBER EHD), Barcelona, Spain (M.P.-A.); Institució Catalana de Recerca i Estudis Avançats, Barcelona, Spain (J.M.-P.); Department of Molecular Plant Physiology and Biophysics, Julius-von-Sachs-Institute, University of Würzburg, Würzburg, Germany (H.K.)
| | - Marçal Pastor-Anglada
- IrsiCaixa Foundation, Hospital Germans Trias i Pujol, Universitat Autònoma de Barcelona, Badalona, Spain (G.M., J.M.-P.); Institute of Anatomy and Cell Biology, University of Würzburg, Würzburg, Germany (C.A., H.K.); Departament de Bioquímica i Biomedicina Molecular, Facultat de Biologia, Institut de Biomedicina, Universitat de Barcelona (IBUB) and Centro de Investigación Biomédica en Red-Enfermedades Hepáticas y Digestivas (CIBER EHD), Barcelona, Spain (M.P.-A.); Institució Catalana de Recerca i Estudis Avançats, Barcelona, Spain (J.M.-P.); Department of Molecular Plant Physiology and Biophysics, Julius-von-Sachs-Institute, University of Würzburg, Würzburg, Germany (H.K.)
| | - Javier Martinez-Picado
- IrsiCaixa Foundation, Hospital Germans Trias i Pujol, Universitat Autònoma de Barcelona, Badalona, Spain (G.M., J.M.-P.); Institute of Anatomy and Cell Biology, University of Würzburg, Würzburg, Germany (C.A., H.K.); Departament de Bioquímica i Biomedicina Molecular, Facultat de Biologia, Institut de Biomedicina, Universitat de Barcelona (IBUB) and Centro de Investigación Biomédica en Red-Enfermedades Hepáticas y Digestivas (CIBER EHD), Barcelona, Spain (M.P.-A.); Institució Catalana de Recerca i Estudis Avançats, Barcelona, Spain (J.M.-P.); Department of Molecular Plant Physiology and Biophysics, Julius-von-Sachs-Institute, University of Würzburg, Würzburg, Germany (H.K.)
| | - Hermann Koepsell
- IrsiCaixa Foundation, Hospital Germans Trias i Pujol, Universitat Autònoma de Barcelona, Badalona, Spain (G.M., J.M.-P.); Institute of Anatomy and Cell Biology, University of Würzburg, Würzburg, Germany (C.A., H.K.); Departament de Bioquímica i Biomedicina Molecular, Facultat de Biologia, Institut de Biomedicina, Universitat de Barcelona (IBUB) and Centro de Investigación Biomédica en Red-Enfermedades Hepáticas y Digestivas (CIBER EHD), Barcelona, Spain (M.P.-A.); Institució Catalana de Recerca i Estudis Avançats, Barcelona, Spain (J.M.-P.); Department of Molecular Plant Physiology and Biophysics, Julius-von-Sachs-Institute, University of Würzburg, Würzburg, Germany (H.K.)
| |
Collapse
|
21
|
Keller T, Gorboulev V, Mueller TD, Dötsch V, Bernhard F, Koepsell H. Rat Organic Cation Transporter 1 Contains Three Binding Sites for Substrate 1-Methyl-4-phenylpyridinium per Monomer. Mol Pharmacol 2018; 95:169-182. [DOI: 10.1124/mol.118.113498] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2018] [Accepted: 11/05/2018] [Indexed: 01/11/2023] Open
|
22
|
Sarmiento-Ortega VE, Brambila E, Flores-Hernández JÁ, Díaz A, Peña-Rosas U, Moroni-González D, Aburto-Luna V, Treviño S. The NOAEL Metformin Dose Is Ineffective against Metabolic Disruption Induced by Chronic Cadmium Exposure in Wistar Rats. TOXICS 2018; 6:E55. [PMID: 30201894 PMCID: PMC6161094 DOI: 10.3390/toxics6030055] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/16/2018] [Revised: 09/06/2018] [Accepted: 09/07/2018] [Indexed: 12/25/2022]
Abstract
Previous studies have proposed that cadmium (Cd) is a metabolic disruptor, which is associated with insulin resistance, metabolic syndrome, and diabetes. This metal is not considered by international agencies for the study of metabolic diseases. In this study, we investigate the effect of metformin on Cd-exposed Wistar rats at a lowest-observed-adverse-effect level (LOAEL) dose (32.5 ppm) in drinking water. Metabolic complications in the rats exposed to Cd were dysglycemia, insulin resistance, dyslipidemia, dyslipoproteinemia, and imbalance in triglyceride and glycogen storage in the liver, muscle, heart, kidney, and adipose tissue. Meanwhile, rats treated orally with a No-observable-adverse-effect level (NOAEL) dose of metformin (200 mg/kg/day) showed mild improvement on serum lipids, but not on glucose tolerance; in tissues, glycogen storage was improved, but lipid storage was ineffective. In conclusion, metformin as a first-line pharmacological therapy must take into consideration the origin and duration of metabolic disruption, because in this work the NOAEL dose of metformin (200 mg/kg/day) showed a limited efficiency in the metabolic disruption caused by chronic Cd exposure.
Collapse
Affiliation(s)
- Victor Enrique Sarmiento-Ortega
- Laboratory of Chemical-Clinical Investigations, Department of Clinical Chemistry, Faculty of Chemistry Science, University Autonomous of Puebla, 14 South. CQ1, University City, Puebla C.P. 72560, Mexico.
| | - Eduardo Brambila
- Laboratory of Chemical-Clinical Investigations, Department of Clinical Chemistry, Faculty of Chemistry Science, University Autonomous of Puebla, 14 South. CQ1, University City, Puebla C.P. 72560, Mexico.
| | - José Ángel Flores-Hernández
- Laboratory of Chemical-Clinical Investigations, Department of Clinical Chemistry, Faculty of Chemistry Science, University Autonomous of Puebla, 14 South. CQ1, University City, Puebla C.P. 72560, Mexico.
| | - Alfonso Díaz
- Department of Pharmacy, Faculty of Chemistry Science, University Autonomous of Puebla, 14 South. CQ1, University City, Puebla C.P. 72560, Mexico.
| | - Ulises Peña-Rosas
- Department of Analytic Chemistry, Faculty of Chemistry Science, University Autonomous of Puebla, 14 South. CQ1, University City, Puebla C.P. 72560, Mexico.
| | - Diana Moroni-González
- Laboratory of Chemical-Clinical Investigations, Department of Clinical Chemistry, Faculty of Chemistry Science, University Autonomous of Puebla, 14 South. CQ1, University City, Puebla C.P. 72560, Mexico.
| | - Violeta Aburto-Luna
- Laboratory of Chemical-Clinical Investigations, Department of Clinical Chemistry, Faculty of Chemistry Science, University Autonomous of Puebla, 14 South. CQ1, University City, Puebla C.P. 72560, Mexico.
| | - Samuel Treviño
- Laboratory of Chemical-Clinical Investigations, Department of Clinical Chemistry, Faculty of Chemistry Science, University Autonomous of Puebla, 14 South. CQ1, University City, Puebla C.P. 72560, Mexico.
| |
Collapse
|
23
|
Mitigation of cell apoptosis induced by ochratoxin A (OTA) is possibly through organic cation transport 2 (OCT2) knockout. Food Chem Toxicol 2018; 121:15-23. [PMID: 30120945 DOI: 10.1016/j.fct.2018.08.026] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2018] [Revised: 08/12/2018] [Accepted: 08/14/2018] [Indexed: 01/06/2023]
Abstract
Ochratoxin A (OTA) is a secondary metabolite of fungi such as Aspergillus ochraceus, A. niger and A. carbonarius, Penicillium verrucosum, and various other Penicillium, Petromyces, and Neopetromyces species. Various foods can be contaminated with OTA, potentially causing several toxic effects such as nephrotoxicity, hepatotoxicity and neurotoxicity. Typically, OTA is excreted by organic anion transporters (OATs). There is no research indicating organic cation transporters (OCTs) are involved in OTA nephrotoxicity. In our study, NRK-52E cells and rats were treated with OTA. OTA changed the expression of OCT1, OCT2 and OCT3 in NRK-52E cells and rat kidneys. TEA alleviated OTA-induced cell death, apoptosis, and DNA damage, and increased ROS. The OCT2 knockout cell line was constructed by the CRISPR/Cas 9 system. OCT2 knockout did not change the gene expression of OCT1, OAT1 and OAT3. OCT2 knockout alleviated the increase of Caspase 3 and CDK1 induced by OTA, leading to a reduction of apoptosis. In addition, OCT2 overexpression increased cell toxicity and expression of Caspase 3. In short, our findings indicate that OCT2 knockout possibly mitigate OTA-induced apoptosis by preventing the increase of Caspase 3 and CDK1.
Collapse
|
24
|
Sandoval PJ, Zorn KM, Clark AM, Ekins S, Wright SH. Assessment of Substrate-Dependent Ligand Interactions at the Organic Cation Transporter OCT2 Using Six Model Substrates. Mol Pharmacol 2018; 94:1057-1068. [PMID: 29884691 DOI: 10.1124/mol.117.111443] [Citation(s) in RCA: 65] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2017] [Accepted: 05/29/2018] [Indexed: 01/08/2023] Open
Abstract
Organic cation transporter (OCT) 2 mediates the entry step for organic cation secretion by renal proximal tubule cells and is a site of unwanted drug-drug interactions (DDIs). But reliance on decision tree-based predictions of DDIs at OCT2 that depend on IC50 values can be suspect because they can be influenced by choice of transported substrate; for example, IC50 values for the inhibition of metformin versus MPP transport can vary by 5- to 10-fold. However, it is not clear whether the substrate dependence of a ligand interaction is common among OCT2 substrates. To address this question, we screened the inhibitory effectiveness of 20 µM concentrations of several hundred compounds against OCT2-mediated uptake of six structurally distinct substrates: MPP, metformin, N,N,N-trimethyl-2-[methyl(7-nitrobenzo[c][1,2,5]oxadiazol-4-yl)amino]ethanaminium (NBD-MTMA), TEA, cimetidine, and 4-4-dimethylaminostyryl-N-methylpyridinium (ASP). Of these, MPP transport was least sensitive to inhibition. IC50 values for 20 structurally diverse compounds confirmed this profile, with IC50 values for MPP averaging 6-fold larger than those for the other substrates. Bayesian machine-learning models of ligand-induced inhibition displayed generally good statistics after cross-validation and external testing. Applying our ASP model to a previously published large-scale screening study for inhibition of OCT2-mediated ASP transport resulted in comparable statistics, with approximately 75% of "active" inhibitors predicted correctly. The differential sensitivity of MPP transport to inhibition suggests that multiple ligands can interact simultaneously with OCT2 and supports the recommendation that MPP not be used as a test substrate for OCT2 screening. Instead, metformin appears to be a comparatively representative OCT2 substrate for both in vitro and in vivo (clinical) use.
Collapse
Affiliation(s)
- Philip J Sandoval
- Department of Physiology, College of Medicine, University of Arizona, Tucson, Arizona (P.J.S., S.H.W.); Collaborations Pharmaceuticals, Inc., Raleigh, North Carolina (K.M.Z., S.E.); and Molecular Materials Informatics, Inc., Montreal, Quebec, Canada (A.M.C.)
| | - Kimberley M Zorn
- Department of Physiology, College of Medicine, University of Arizona, Tucson, Arizona (P.J.S., S.H.W.); Collaborations Pharmaceuticals, Inc., Raleigh, North Carolina (K.M.Z., S.E.); and Molecular Materials Informatics, Inc., Montreal, Quebec, Canada (A.M.C.)
| | - Alex M Clark
- Department of Physiology, College of Medicine, University of Arizona, Tucson, Arizona (P.J.S., S.H.W.); Collaborations Pharmaceuticals, Inc., Raleigh, North Carolina (K.M.Z., S.E.); and Molecular Materials Informatics, Inc., Montreal, Quebec, Canada (A.M.C.)
| | - Sean Ekins
- Department of Physiology, College of Medicine, University of Arizona, Tucson, Arizona (P.J.S., S.H.W.); Collaborations Pharmaceuticals, Inc., Raleigh, North Carolina (K.M.Z., S.E.); and Molecular Materials Informatics, Inc., Montreal, Quebec, Canada (A.M.C.)
| | - Stephen H Wright
- Department of Physiology, College of Medicine, University of Arizona, Tucson, Arizona (P.J.S., S.H.W.); Collaborations Pharmaceuticals, Inc., Raleigh, North Carolina (K.M.Z., S.E.); and Molecular Materials Informatics, Inc., Montreal, Quebec, Canada (A.M.C.)
| |
Collapse
|
25
|
Visentin M, Torozi A, Gai Z, Häusler S, Li C, Hiller C, Schraml PH, Moch H, Kullak-Ublick GA. Fluorocholine Transport Mediated by the Organic Cation Transporter 2 (OCT2, SLC22A2): Implication for Imaging of Kidney Tumors. Drug Metab Dispos 2018; 46:1129-1136. [DOI: 10.1124/dmd.118.081091] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2018] [Accepted: 05/16/2018] [Indexed: 12/17/2022] Open
|
26
|
Gorboulev V, Rehman S, Albert CM, Roth U, Meyer MJ, Tzvetkov MV, Mueller TD, Koepsell H. Assay Conditions Influence Affinities of Rat Organic Cation Transporter 1: Analysis of Mutagenesis in the Modeled Outward-Facing Cleft by Measuring Effects of Substrates and Inhibitors on Initial Uptake. Mol Pharmacol 2018; 93:402-415. [DOI: 10.1124/mol.117.110767] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2017] [Accepted: 01/12/2018] [Indexed: 12/15/2022] Open
|
27
|
Visentin M, Gai Z, Torozi A, Hiller C, Kullak-Ublick GA. Colistin is Substrate of the Carnitine/Organic Cation Transporter 2 (OCTN2, SLC22A5). Drug Metab Dispos 2017; 45:1240-1244. [DOI: 10.1124/dmd.117.077248] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2017] [Accepted: 10/03/2017] [Indexed: 11/22/2022] Open
|
28
|
Hyung S, Pyeon W, Park JE, Song YK, Chung SJ. The conditional stimulation of rat organic cation transporter 2, but not its human ortholog, by mesoridazine: the possibility of the involvement of the high-affinity binding site of the transporter in the stimulation. J Pharm Pharmacol 2017; 69:1513-1523. [DOI: 10.1111/jphp.12799] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2017] [Accepted: 07/17/2017] [Indexed: 12/29/2022]
Abstract
Abstract
Objectives
To study the functional consequences of the human and rat forms of OCT2 in the presence of phenothiazines.
Methods
MDCK cells expressing human or rat OCT2 were established, and MPP+ transport was determined by uptake assays. Concentration dependency was studied for the stimulatory/inhibitory effects of phenothiazines on MPP+ transport.
Key findings
Among the 11 phenothiazines examined, the majority were found to have comparable effects on transporter function between the orthologous forms, while three phenothiazines, particularly mesoridazine, had complex impacts on transporter function. For rOCT2, mesoridazine stimulated transport at 0.1 and 1 μmMPP+ with the mesoridazine concentration–uptake curve becoming bell-shaped. This conditional effect became less pronounced at 30 μmMPP+, resulting in an inhibition curve with a typical profile. For hOCT2, mesoridazine behaved as a typical inhibitor of transporter function at all MPP+ concentrations, although the kinetics of inhibition were still affected by the substrate concentration.
Conclusions
The conditional stimulation by mesoridazine in rOCT2, and the lack thereof in hOCT2, may be a manifestation of the interaction of phenothiazine with substrate binding at the high-affinity site of the OCT2. As OCT2 was previously indicated in some drug–drug interactions, the conditional stimulation of OCT2 and its potential species-differences may be of practical relevance.
Collapse
Affiliation(s)
- Sungwoo Hyung
- College of Pharmacy, Seoul National University, Gwanak-gu, Seoul, Korea
| | - Wonji Pyeon
- College of Pharmacy, Seoul National University, Gwanak-gu, Seoul, Korea
| | - Ji Eun Park
- College of Pharmacy, Seoul National University, Gwanak-gu, Seoul, Korea
| | - Yoo-Kyung Song
- College of Pharmacy, Seoul National University, Gwanak-gu, Seoul, Korea
| | - Suk-Jae Chung
- College of Pharmacy, Seoul National University, Gwanak-gu, Seoul, Korea
- Research Institute of Pharmaceutical Sciences, College of Pharmacy, Seoul National University, Gwanak-gu, Seoul, Korea
| |
Collapse
|
29
|
Xenobiotic transporters and kidney injury. Adv Drug Deliv Rev 2017; 116:73-91. [PMID: 28111348 DOI: 10.1016/j.addr.2017.01.005] [Citation(s) in RCA: 73] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2016] [Revised: 01/02/2017] [Accepted: 01/13/2017] [Indexed: 02/07/2023]
Abstract
Renal proximal tubules are targets for toxicity due in part to the expression of transporters that mediate the secretion and reabsorption of xenobiotics. Alterations in transporter expression and/or function can enhance the accumulation of toxicants and sensitize the kidneys to injury. This can be observed when xenobiotic uptake by carrier proteins is increased or efflux of toxicants and their metabolites is reduced. Nephrotoxic chemicals include environmental contaminants (halogenated hydrocarbon solvents, the herbicide paraquat, the fungal toxin ochratoxin, and heavy metals) as well as pharmaceuticals (certain beta-lactam antibiotics, antiviral drugs, and chemotherapeutic drugs). This review explores the mechanisms by which transporters mediate the entry and exit of toxicants from renal tubule cells and influence the degree of kidney injury. Delineating how transport proteins regulate the renal accumulation of toxicants is critical for understanding the likelihood of nephrotoxicity resulting from competition for excretion or genetic polymorphisms that affect transporter function.
Collapse
|
30
|
Orr SE, Bridges CC. Chronic Kidney Disease and Exposure to Nephrotoxic Metals. Int J Mol Sci 2017; 18:ijms18051039. [PMID: 28498320 PMCID: PMC5454951 DOI: 10.3390/ijms18051039] [Citation(s) in RCA: 200] [Impact Index Per Article: 28.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2017] [Accepted: 04/26/2017] [Indexed: 12/26/2022] Open
Abstract
Chronic kidney disease (CKD) is a common progressive disease that is typically characterized by the permanent loss of functional nephrons. As injured nephrons become sclerotic and die, the remaining healthy nephrons undergo numerous structural, molecular, and functional changes in an attempt to compensate for the loss of diseased nephrons. These compensatory changes enable the kidney to maintain fluid and solute homeostasis until approximately 75% of nephrons are lost. As CKD continues to progress, glomerular filtration rate decreases, and remaining nephrons are unable to effectively eliminate metabolic wastes and environmental toxicants from the body. This inability may enhance mortality and/or morbidity of an individual. Environmental toxicants of particular concern are arsenic, cadmium, lead, and mercury. Since these metals are present throughout the environment and exposure to one or more of these metals is unavoidable, it is important that the way in which these metals are handled by target organs in normal and disease states is understood completely.
Collapse
Affiliation(s)
- Sarah E Orr
- Mercer University School of Medicine, Division of Basic Medical Sciences, 1550 College St., Macon, GA 31207, USA.
| | - Christy C Bridges
- Mercer University School of Medicine, Division of Basic Medical Sciences, 1550 College St., Macon, GA 31207, USA.
| |
Collapse
|
31
|
Chedik L, Bruyere A, Le Vee M, Stieger B, Denizot C, Parmentier Y, Potin S, Fardel O. Inhibition of Human Drug Transporter Activities by the Pyrethroid Pesticides Allethrin and Tetramethrin. PLoS One 2017; 12:e0169480. [PMID: 28099443 PMCID: PMC5242521 DOI: 10.1371/journal.pone.0169480] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2016] [Accepted: 12/16/2016] [Indexed: 12/11/2022] Open
Abstract
Pyrethroids are widely-used chemical insecticides, to which humans are commonly exposed, and known to alter functional expression of drug metabolizing enzymes. Limited data have additionally suggested that drug transporters, that constitute key-actors of the drug detoxification system, may also be targeted by pyrethroids. The present study was therefore designed to analyze the potential regulatory effects of these pesticides towards activities of main ATP-binding cassette (ABC) and solute carrier (SLC) drug transporters, using transporter-overexpressing cells. The pyrethroids allethrin and tetramethrin were found to inhibit various ABC and SLC drug transporters, including multidrug resistance-associated protein (MRP) 2, breast cancer resistance protein (BCRP), organic anion transporter polypeptide (OATP) 1B1, organic anion transporter (OAT) 3, multidrug and toxin extrusion transporter (MATE) 1, organic cation transporter (OCT) 1 and OCT2, with IC50 values however ranging from 2.6 μM (OCT1 inhibition by allethrin) to 77.6 μM (OAT3 inhibition by tetramethrin) and thus much higher than pyrethroid concentrations (in the nM range) reached in environmentally pyrethroid-exposed humans. By contrast, allethrin and tetramethrin cis-stimulated OATP2B1 activity and failed to alter activities of OATP1B3, OAT1 and MATE2-K, whereas P-glycoprotein activity was additionally moderately inhibited. Twelve other pyrethoids used at 100 μM did not block activities of the various investigated transporters, or only moderately inhibited some of them (inhibition by less than 50%). In silico analysis of structure-activity relationships next revealed that molecular parameters, including molecular weight and lipophilicity, are associated with transporter inhibition by allethrin/tetramethrin and successfully predicted transporter inhibition by the pyrethroids imiprothrin and prallethrin. Taken together, these data fully demonstrated that two pyrethoids, i.e., allethrin and tetramethrin, can act as regulators of the activity of various ABC and SLC drug transporters, but only when used at high and non-relevant concentrations, making unlikely any contribution of these transporter activity alterations to pyrethroid toxicity in environmentally exposed humans.
Collapse
Affiliation(s)
- Lisa Chedik
- Institut de Recherches en Santé, Environnement et Travail (IRSET), UMR INSERM U1085, Faculté de Pharmacie, 2 Avenue du Pr Léon Bernard, Rennes, France
- Pôle Pharmacie, Centre Hospitalier Universitaire, 2 rue Henri Le Guilloux, Rennes, France
| | - Arnaud Bruyere
- Institut de Recherches en Santé, Environnement et Travail (IRSET), UMR INSERM U1085, Faculté de Pharmacie, 2 Avenue du Pr Léon Bernard, Rennes, France
| | - Marc Le Vee
- Institut de Recherches en Santé, Environnement et Travail (IRSET), UMR INSERM U1085, Faculté de Pharmacie, 2 Avenue du Pr Léon Bernard, Rennes, France
| | - Bruno Stieger
- Department of Clinical Pharmacology and Toxicology, University Hospital Zurich, University of Zurich, Rämistrasse 100, Zurich, Switzerland
| | - Claire Denizot
- Centre de Pharmacocinétique, Technologie Servier, 25–27 rue Eugène Vignat, Orléans, France
| | - Yannick Parmentier
- Centre de Pharmacocinétique, Technologie Servier, 25–27 rue Eugène Vignat, Orléans, France
| | - Sophie Potin
- Institut de Recherches en Santé, Environnement et Travail (IRSET), UMR INSERM U1085, Faculté de Pharmacie, 2 Avenue du Pr Léon Bernard, Rennes, France
- Pôle Pharmacie, Centre Hospitalier Universitaire, 2 rue Henri Le Guilloux, Rennes, France
| | - Olivier Fardel
- Institut de Recherches en Santé, Environnement et Travail (IRSET), UMR INSERM U1085, Faculté de Pharmacie, 2 Avenue du Pr Léon Bernard, Rennes, France
- Pôle Biologie, Centre Hospitalier Universitaire, 2 rue Henri Le Guilloux, Rennes, France
| |
Collapse
|
32
|
Visentin M, van Rosmalen BV, Hiller C, Bieze M, Hofstetter L, Verheij J, Kullak-Ublick GA, Koepsell H, Phoa SS, Tamai I, Bennink RJ, van Gulik TM, Stieger B. Impact of Organic Cation Transporters (OCT-SLC22A) on Differential Diagnosis of Intrahepatic Lesions. Drug Metab Dispos 2016; 45:166-173. [DOI: 10.1124/dmd.116.072371] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2016] [Accepted: 11/28/2016] [Indexed: 01/20/2023] Open
|
33
|
Yang H, Guo D, Obianom ON, Su T, Polli JE, Shu Y. Multidrug and toxin extrusion proteins mediate cellular transport of cadmium. Toxicol Appl Pharmacol 2016; 314:55-62. [PMID: 27871888 DOI: 10.1016/j.taap.2016.11.007] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2016] [Revised: 11/15/2016] [Accepted: 11/17/2016] [Indexed: 01/13/2023]
Abstract
Cadmium (Cd) is an environmentally prevalent toxicant posing increasing risk to human health worldwide. As compared to the extensive research in Cd tissue accumulation, little was known about the elimination of Cd, particularly its toxic form, Cd ion (Cd2+). In this study, we aimed to examine whether Cd2+ is a substrate of multidrug and toxin extrusion proteins (MATEs) that are important in renal xenobiotic elimination. HEK-293 cells overexpressing the human MATE1 (HEK-hMATE1), human MATE2-K (HEK-hMATE2-K) and mouse Mate1 (HEK-mMate1) were used to study the cellular transport and toxicity of Cd2+. The cells overexpressing MATEs showed a 2-4 fold increase of Cd2+ uptake that could be blocked by the MATE inhibitor cimetidine. A saturable transport profile was observed with the Michaelis-Menten constant (Km) of 130±15.8μM for HEK-hMATE1; 139±21.3μM for HEK-hMATE2-K; and 88.7±13.5μM for HEK-mMate1, respectively. Cd2+ could inhibit the uptake of metformin, a substrate of MATE transporters, with the half maximal inhibitory concentration (IC50) of 97.5±6.0μM, 20.2±2.6μM, and 49.9±6.9μM in HEK-hMATE1, HEK-hMATE2-K, and HEK-mMate1 cells, respectively. In addition, hMATE1 could transport preloaded Cd2+ out of the HEK-hMATE1 cells, thus resulting in a significant decrease of Cd2+-induced cytotoxicity. The present study has provided the first evidence supporting that MATEs transport Cd2+ and may function as cellular elimination machinery in Cd intoxication.
Collapse
Affiliation(s)
- Hong Yang
- Department of Pharmaceutical Sciences, School of Pharmacy, University of Maryland at Baltimore, MD, USA
| | - Dong Guo
- Department of Pharmaceutical Sciences, School of Pharmacy, University of Maryland at Baltimore, MD, USA
| | - Obinna N Obianom
- Department of Pharmaceutical Sciences, School of Pharmacy, University of Maryland at Baltimore, MD, USA
| | - Tong Su
- Department of Oral Maxillofacial Surgery, the First Affiliated Hospital, Xiangya Medical School, Central South University, Hunan 410007, China
| | - James E Polli
- Department of Pharmaceutical Sciences, School of Pharmacy, University of Maryland at Baltimore, MD, USA
| | - Yan Shu
- Department of Pharmaceutical Sciences, School of Pharmacy, University of Maryland at Baltimore, MD, USA.
| |
Collapse
|
34
|
Thévenod F, Wolff NA. Iron transport in the kidney: implications for physiology and cadmium nephrotoxicity. Metallomics 2016; 8:17-42. [PMID: 26485516 DOI: 10.1039/c5mt00215j] [Citation(s) in RCA: 62] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The kidney has recently emerged as an organ with a significant role in systemic iron (Fe) homeostasis. Substantial amounts of Fe are filtered by the kidney, which have to be reabsorbed to prevent Fe deficiency. Accordingly Fe transporters and receptors for protein-bound Fe are expressed in the nephron that may also function as entry pathways for toxic metals, such as cadmium (Cd), by way of "ionic and molecular mimicry". Similarities, but also differences in handling of Cd by these transport routes offer rationales for the propensity of the kidney to develop Cd toxicity. This critical review provides a comprehensive update on Fe transport by the kidney and its relevance for physiology and Cd nephrotoxicity. Based on quantitative considerations, we have also estimated the in vivo relevance of the described transport pathways for physiology and toxicology. Under physiological conditions all segments of the kidney tubules are likely to utilize Fe for cellular Fe requiring processes for metabolic purposes and also to contribute to reabsorption of free and bound forms of Fe into the circulation. But Cd entering tubule cells disrupts metabolic pathways and is unable to exit. Furthermore, our quantitative analyses contest established models linking chronic Cd nephrotoxicity to proximal tubular uptake of metallothionein-bound Cd. Hence, Fe transport by the kidney may be beneficial by preventing losses from the body. But increased uptake of Fe or Cd that cannot exit tubule cells may lead to kidney injury, and Fe deficiency may facilitate renal Cd uptake.
Collapse
Affiliation(s)
- Frank Thévenod
- Institute of Physiology, Pathophysiology & Toxicology, Center for Biomedical Training and Research (ZBAF), University of Witten/Herdecke, Stockumer Str. 12, 58453 Witten, Germany.
| | - Natascha A Wolff
- Institute of Physiology, Pathophysiology & Toxicology, Center for Biomedical Training and Research (ZBAF), University of Witten/Herdecke, Stockumer Str. 12, 58453 Witten, Germany.
| |
Collapse
|
35
|
Organic Cation Transporter 2 Overexpression May Confer an Increased Risk of Gentamicin-Induced Nephrotoxicity. Antimicrob Agents Chemother 2016; 60:5573-80. [PMID: 27401566 DOI: 10.1128/aac.00907-16] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2016] [Accepted: 07/03/2016] [Indexed: 01/11/2023] Open
Abstract
Nephrotoxicity is a relevant limitation of gentamicin, and obese patients have an increased risk for gentamicin-induced kidney injury. This damage is thought to depend on the accumulation of the drug in the renal cortex. Obese rats showed substantially higher levels of gentamicin in the kidney than did lean animals. This study characterized the role of organic cation transporters (OCTs) in gentamicin transport and elucidated their possible contribution in the increased renal accumulation of gentamicin in obesity. The mRNA and protein expression levels of the organic cation transporters Oct2 (Slc22a2) and Oct3 (Slc22a3) were increased in kidney samples from obese mice fed a high-fat diet. Similarly, OCT2 (∼2-fold) and OCT3 (∼3-fold) showed increased protein expression in the kidneys of obese patients compared with those of nonobese individuals. Using HEK293 cells overexpressing the different OCTs, human OCT2 was found to transport [(3)H]gentamicin with unique sigmoidal kinetics typical of homotropic positive cooperativity (autoactivation). In mouse primary proximal tubular cells, [(3)H]gentamicin uptake was reduced by approximately 40% when the cells were coincubated with the OCT2 substrate metformin. The basolateral localization of OCT2 suggests that gentamicin can enter proximal tubular cells from the blood side, probably as part of a slow tubular secretion process that may influence intracellular drug concentrations and exposure time. Increased expression of OCT2 may explain the higher accumulation of gentamicin, thereby conferring an increased risk of renal toxicity in obese patients.
Collapse
|
36
|
Martínez-Guerrero LJ, Morales M, Ekins S, Wright SH. Lack of Influence of Substrate on Ligand Interaction with the Human Multidrug and Toxin Extruder, MATE1. Mol Pharmacol 2016; 90:254-64. [PMID: 27418674 DOI: 10.1124/mol.116.105056] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2016] [Accepted: 06/30/2016] [Indexed: 12/14/2022] Open
Abstract
Multidrug and toxin extruder (MATE) 1 plays a central role in mediating renal secretion of organic cations, a structurally diverse collection of compounds that includes ∼40% of prescribed drugs. Because inhibition of transport activity of other multidrug transporters, including the organic cation transporter (OCT) 2, is influenced by the structure of the transported substrate, the present study screened over 400 drugs as inhibitors of the MATE1-mediated transport of four structurally distinct organic cation substrates: the commonly used drugs: 1) metformin and 2) cimetidine; and two prototypic cationic substrates, 3) 1-methyl-4-phenylpyridinium (MPP), and 4) the novel fluorescent probe, N,N,N-trimethyl-2-[methyl(7-nitrobenzo[c][1,2,5]oxadiazol-4-yl)amino]ethanaminium iodide. Transport was measured in Chinese hamster ovary cells that stably expressed the human ortholog of MATE1. Comparison of the resulting inhibition profiles revealed no systematic influence of substrate structure on inhibitory efficacy. Similarly, IC50 values for 26 structurally diverse compounds revealed no significant influence of substrate structure on the kinetic interaction of inhibitor with MATE1. The IC50 data were used to generate three-dimensional quantitative pharmacophores that identified hydrophobic regions, H-bond acceptor sites, and an ionizable (cationic) feature as key determinants for ligand binding to MATE1. In summary, in contrast to the behavior observed with some other multidrug transporters, including OCT2, the results suggest that substrate identity exerts comparatively little influence on ligand interaction with MATE1.
Collapse
Affiliation(s)
- Lucy J Martínez-Guerrero
- Department of Physiology, College of Medicine, University of Arizona, Tucson, Arizona (L.J.M.-G., M.M., S.H.W.); and Collaborations in Chemistry, Fuquay-Varina, North Carolina (S.E.)
| | - Mark Morales
- Department of Physiology, College of Medicine, University of Arizona, Tucson, Arizona (L.J.M.-G., M.M., S.H.W.); and Collaborations in Chemistry, Fuquay-Varina, North Carolina (S.E.)
| | - Sean Ekins
- Department of Physiology, College of Medicine, University of Arizona, Tucson, Arizona (L.J.M.-G., M.M., S.H.W.); and Collaborations in Chemistry, Fuquay-Varina, North Carolina (S.E.)
| | - Stephen H Wright
- Department of Physiology, College of Medicine, University of Arizona, Tucson, Arizona (L.J.M.-G., M.M., S.H.W.); and Collaborations in Chemistry, Fuquay-Varina, North Carolina (S.E.)
| |
Collapse
|
37
|
Jakobsen S, Busk M, Jensen JB, Munk OL, Zois NE, Alstrup AKO, Jessen N, Frøkiær J. A PET Tracer for Renal Organic Cation Transporters, ¹¹C-Metformin: Radiosynthesis and Preclinical Proof-of-Concept Studies. J Nucl Med 2016; 57:615-21. [PMID: 26769859 DOI: 10.2967/jnumed.115.169292] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2015] [Accepted: 12/17/2015] [Indexed: 12/28/2022] Open
Abstract
UNLABELLED Organic cation transporters (OCTs) in the kidney proximal tubule (PT) participate in renal excretion of drugs and endogenous compounds. PT function is commonly impaired in kidney diseases, and consequently quantitative measurement of OCT function may provide an important estimate of kidney function. Metformin is a widely used drug and targets OCT type 2 located in the PT. Thus, we hypothesized that (11)C-labeled metformin would be a suitable PET tracer for quantification of renal function. METHODS (11)C-metformin was prepared by (11)C-methylation of 1-methylbiguanide. In vitro cell uptake of (11)C-metformin was studied in LLC-PK1 cells in the presence of increasing doses of unlabeled metformin. In vivo small-animal PET studies in Sprague-Dawley rats were performed at baseline and after treatment with OCT inhibitors to evaluate renal uptake of (11)C-metformin. Kidney and liver pharmacokinetics of (11)C-metformin was investigated in vivo by dynamic (11)C-metformin PET/CT in 6 anesthetized pigs, and renal clearance of (11)C-metformin was compared with renal clearance of (51)Cr-ethylenediaminetetraacetic acid (EDTA). Formation of (11)C metabolites was investigated by analysis of blood and urine samples. RESULTS The radiochemical yield of (11)C-metformin was 15% ± 3% (n= 40, decay-corrected), and up to 1.5 GBq of tracer were produced with a radiochemical purity greater than 95% in less than 30 min. Dose-dependent uptake of (11)C-metformin in LLC-PK1 cells was rapid. Rat small-animal PET images showed (11)C-metformin uptake in the kidney and liver, the kinetics of which were changed after challenging animals with OCT inhibitors. In pigs, 80% of the injected metformin dose was rapidly present in the kidney, and a high dose of metformin caused a delayed renal uptake and clearance compared with baseline consistent with transporter-mediated competition. Renal clearance of (11)C-metformin was approximately 3 times the renal clearance of (51)Cr-EDTA. CONCLUSION We successfully synthesized an (11)C-metformin tracer, and PET studies in rats and pigs showed a rapid kidney uptake from the blood and excretion into the bladder similar to other radiopharmaceuticals developed for γ-camera renography.
Collapse
Affiliation(s)
| | - Morten Busk
- Department of Experimental Oncology, Aarhus University Hospital, Aarhus, Denmark; and
| | - Jonas Brorson Jensen
- PET Center, Aarhus University Hospital, Aarhus, Denmark Department of Clinical Medicine, Aarhus University, Denmark
| | | | | | | | - Niels Jessen
- Department of Clinical Medicine, Aarhus University, Denmark
| | | |
Collapse
|
38
|
Visentin M, Stieger B, Merz M, Kullak-Ublick GA. Octreotide inhibits the bilirubin carriers organic anion transporting polypeptides 1B1 and 1B3 and the multidrug resistance-associated protein 2. J Pharmacol Exp Ther 2015; 355:145-51. [PMID: 26330539 DOI: 10.1124/jpet.115.227546] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2015] [Accepted: 08/31/2015] [Indexed: 08/30/2023] Open
Abstract
The somatostatin analog octreotide can lead to hyperbilirubinemia without evidence of liver injury. Here we investigate whether octreotide inhibits the main sinusoidal/canalicular bilirubin carriers and whether it is a transport substrate. Octreotide showed the most potent inhibitory effect toward OATP1B1-mediated transport and weaker inhibition for OATP1B3- and MRP2-mediated transport. Octreotide had no effect on OATP2B1-mediated transport. Octreotide inhibited [(3)H]estradiol-17-β-glucuronide (E17βG) influx mediated by OATP1B1, 1B3, and multidrug resistance-associated protein 2 (MRP2) in a concentration-dependent manner, and the IC50 values were computed to be 23 μM (95% confidence interval [CI] 18-29), 68 μM (95% CI 50-91), and 116.6 μM (95% CI 74.5-182.4), respectively. The interaction between octreotide and OATP1B1 was further studied. Inhibition of [(3)H]E17βG OATP1B1-mediated transport was purely competitive with no changes in maximum transport capacity (Vmax) and a twofold Km increase when the influx kinetics of [(3)H]E17βG were measured in the presence of octreotide (8.8 ± 3.1 versus 4.4 ± 1.2 μM, P = 0.03). The inhibition constant (Ki) of octreotide for the transport of [(3)H]E17βG was calculated at 33.5 ± 5.5 μM. Uptake of radiolabeled octreotide by OATP1B1-CHO cells was higher than in wild-type CHO cells and nonlabeled octreotide at the extracellular compartment was able to trans-stimulate the OATP1B1-mediated efflux of intracellular [(3)H]E17βG, suggesting that octreotide is a substrate of OATP1B1. In summary, this study shows interaction of octreotide on the human hepatocellular bilirubin transporters OATP1B1, OATP1B3, and MRP2, notably OATP1B1. These findings are in line with the clinical observation that a fraction of patients under treatment with octreotide exhibit hyperbilirubinemia.
Collapse
Affiliation(s)
- Michele Visentin
- Department of Clinical Pharmacology and Toxicology, University Hospital Zurich, Switzerland (M.V., B.S., G.A.K.-U.); and Discovery and Investigative Safety, Novartis Institutes for BioMedical Research, Basel, Switzerland (M.M., G.A.K.-U.)
| | - Bruno Stieger
- Department of Clinical Pharmacology and Toxicology, University Hospital Zurich, Switzerland (M.V., B.S., G.A.K.-U.); and Discovery and Investigative Safety, Novartis Institutes for BioMedical Research, Basel, Switzerland (M.M., G.A.K.-U.)
| | - Michael Merz
- Department of Clinical Pharmacology and Toxicology, University Hospital Zurich, Switzerland (M.V., B.S., G.A.K.-U.); and Discovery and Investigative Safety, Novartis Institutes for BioMedical Research, Basel, Switzerland (M.M., G.A.K.-U.)
| | - Gerd A Kullak-Ublick
- Department of Clinical Pharmacology and Toxicology, University Hospital Zurich, Switzerland (M.V., B.S., G.A.K.-U.); and Discovery and Investigative Safety, Novartis Institutes for BioMedical Research, Basel, Switzerland (M.M., G.A.K.-U.)
| |
Collapse
|
39
|
Hacker K, Maas R, Kornhuber J, Fromm MF, Zolk O. Substrate-Dependent Inhibition of the Human Organic Cation Transporter OCT2: A Comparison of Metformin with Experimental Substrates. PLoS One 2015; 10:e0136451. [PMID: 26327616 PMCID: PMC4556614 DOI: 10.1371/journal.pone.0136451] [Citation(s) in RCA: 78] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2015] [Accepted: 08/03/2015] [Indexed: 02/03/2023] Open
Abstract
The importance of the organic cation transporter OCT2 in the renal excretion of cationic drugs raises the possibility of drug-drug interactions (DDIs) in which an inhibitor (perpetrator) drug decreases OCT2-dependent renal clearance of a victim (substrate) drug. In fact, there are clinically significant interactions for drugs that are known substrates of OCT2 such as metformin. To identify drugs as inhibitors for OCT2, individual drugs or entire drug libraries have been investigated in vitro by using experimental probe substrates such as 1-methyl-4-phenylpyridinium (MPP+) or 4–4-dimethylaminostyryl-N-methylpyridinium (ASP+). It has been questioned whether the inhibition data obtained with an experimental probe substrate such as MPP+ or ASP+ might be used to predict the inhibition against other, clinical relevant substrates such as metformin. Here we compared the OCT2 inhibition profile data for the substrates metformin, MPP+ and ASP+. We used human embryonic kidney (HEK 293) cells stably overexpressing human OCT2 as the test system to screen 125 frequently prescribed drugs as inhibitors of OCT2-mediated metformin and MPP+ uptake. Data on inhibition of OCT2-mediated ASP+ uptake were obtained from previous literature. A moderate correlation between the inhibition of OCT2-mediated MPP+, ASP+, and metformin uptake was observed (pairwise rs between 0.27 and 0.48, all P < 0.05). Of note, the correlation in the inhibition profile between structurally similar substrates such as MPP+ and ASP+ (Tanimoto similarity T = 0.28) was even lower (rs = 0.27) than the correlation between structurally distinct substrates, such as ASP+ and metformin (T = 0.01; rs = 0.48) or MPP+ and metformin (T = 0.01; rs = 0.40). We identified selective as well as universal OCT2 inhibitors, which inhibited transport by more than 50% of one substrate only or of all substrates, respectively. Our data suggest that the predictive value for drug-drug interactions using experimental substrates rather than the specific victim drug is limited.
Collapse
Affiliation(s)
- Kristina Hacker
- Institute of Experimental and Clinical Pharmacology and Toxicology, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
| | - Renke Maas
- Institute of Experimental and Clinical Pharmacology and Toxicology, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
| | - Johannes Kornhuber
- Department of Psychiatry and Psychotherapy, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
| | - Martin F. Fromm
- Institute of Experimental and Clinical Pharmacology and Toxicology, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
- * E-mail:
| | - Oliver Zolk
- Institute of Experimental and Clinical Pharmacology and Toxicology, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
- Institute of Pharmacology of Natural Products & Clinical Pharmacology, Ulm University, Ulm, Germany
| |
Collapse
|
40
|
Abstract
INTRODUCTION Organic cation transporters OCT1, OCT2 and OCT3 expressed in the small intestine, liver, brain and other organs play important roles in absorption, excretion and distribution of cationic drugs. Drug-drug interactions at OCTs may change pharmacokinetics, pharmacodynamics and drug toxicity. Knowledge about physiological and biomedical functions of OCTs and the molecular mechanisms of transport and inhibition is required to anticipate drug-drug interactions and their potential biomedical impact. AREAS COVERED Current knowledge about structure, polyspecific cation binding and transport of OCTs is summarized. Tissue distributions of OCT1-3 and their presumed physiological roles in the small intestine, liver, kidney and brain are reported, and drugs that are transported by human OCT1-3 are listed. The impact of human OCTs for pharmacokinetics and pharmacodynamics of the antidiabetic metformin and antineoplastic platinum derivatives are discussed. In addition, interactions of drugs that are transported by OCTs observed in the kidney and liver are reported. Procedures to test novel drugs for drug-drug interactions at OCTs in vitro and in clinical studies are recommended. EXPERT OPINION When performing in vitro testing for drug-drug interactions, it must be considered that one inhibitory drug may inhibit different transported drugs with different affinities. After positive in vitro testing for drug-drug interaction, clinical tests are obligatory.
Collapse
Affiliation(s)
- Hermann Koepsell
- a University Würzburg, Julius-von-Sachs-Institute, Department of Molecular Plant Physiology and Biophysics , Botanik 1, Julius-von-Sachs-Platz 2, Würzburg 97082, Germany
| |
Collapse
|
41
|
Role of organic cation transporters (OCTs) in the brain. Pharmacol Ther 2015; 146:94-103. [DOI: 10.1016/j.pharmthera.2014.09.008] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2014] [Accepted: 09/18/2014] [Indexed: 01/04/2023]
|
42
|
Ljubojević M, Breljak D, Herak-Kramberger CM, Anzai N, Sabolić I. Expression of basolateral organic anion and cation transporters in experimental cadmium nephrotoxicity in rat kidney. Arch Toxicol 2015; 90:525-41. [DOI: 10.1007/s00204-015-1450-8] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2014] [Accepted: 01/06/2015] [Indexed: 01/11/2023]
|
43
|
Li X, Sun X, Chen J, Lu Y, Zhang Y, Wang C, Li J, Zhang Q, Zhao D, Chen X. Investigation of the role of organic cation transporter 2 (OCT2) in the renal transport of guanfacine, a selective α2A-adrenoreceptor agonist. Xenobiotica 2014; 45:88-94. [DOI: 10.3109/00498254.2014.949904] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
|