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Casu F, Watson AM, Yost J, Gaylord TG, Bearden DW, Denson MR. Evaluation of a hepatic biomarker of nutritional imbalance in juvenile red drum ( Sciaenops ocellatus) fed 60% soybean meal-based diets using NMR-based metabolomics. ANIMAL NUTRITION (ZHONGGUO XU MU SHOU YI XUE HUI) 2024; 16:45-61. [PMID: 38144431 PMCID: PMC10746370 DOI: 10.1016/j.aninu.2023.03.014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/18/2022] [Revised: 03/22/2023] [Accepted: 03/28/2023] [Indexed: 12/26/2023]
Abstract
A 12-week feeding trial with juvenile red drum (Sciaenops ocellatus) fed high-soybean meal (SBM) diets was conducted to investigate a putative biomarker of nutritional imbalance, N-formimino-L-glutamate (FIGLU). Three fishmeal-free, 60% SBM pelleted diets (named B12, Fol, and Met, respectively) were tested to evaluate the effects on growth performance and tissue metabolite profiles of supplementation of vitamin B12 (0.012 mg/kg), folate (10 mg/kg), methionine (1 g/kg) respectively, above basal supplementation levels. A fourth SBM-based diet (named B12/Fol/Met) was formulated with a combination of B12, folate, and methionine to attain the above-mentioned target concentrations. A fifth 60% SBM diet (named FWS) with methionine supplementation (1 g/kg above basal supplementation levels), enriched with taurine, lysine and threonine as well as minerals, was also tested. This diet contained formulation targets and additives which have allowed for replacing fishmeal with plant proteins in rainbow trout feeds. Control diets included a fishmeal-based diet (named FM), an unsupplemented basal 60% SBM diet (named SBM60), and a "natural" diet (named N) made up of equal parts of fish (cigar minnows), squid and shrimp as a positive reference for growth performance. Formulated feeds contained approximately 37% total crude protein, approximately 14% total crude lipid and were energetically balanced. Standard growth performance metrics were measured, and tissues (liver, muscle) were collected at week 12 to evaluate diet-induced metabolic changes using nuclear magnetic resonance (NMR)-based metabolomics. Our results show that the FWS diet outperformed all other SBM diets and the FM diet under all performance metrics (P < 0.05). FIGLU was not detected in fish fed the N diet but was detected in those fed the SBM diets and the FM diet. Fish fed the FWS diet and the Met diet showed lower hepatic levels of FIGLU compared with the other SBM-based diets (P < 0.05), suggesting that among the different supplementation regimes, methionine supplementation was associated with lower FIGLU levels. The FWS diet produced tissue metabolite profiles that were more similar to those of fish fed the N diet. Based on our results, the FWS diet constitutes a promising SBM-based alternative diet to fishmeal for red drum.
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Affiliation(s)
- Fabio Casu
- Marine Resources Research Institute, South Carolina Department of Natural Resources, 217 Fort Johnson Road, Charleston, SC 29412, USA
| | - Aaron M. Watson
- Marine Resources Research Institute, South Carolina Department of Natural Resources, 217 Fort Johnson Road, Charleston, SC 29412, USA
| | - Justin Yost
- Marine Resources Research Institute, South Carolina Department of Natural Resources, 217 Fort Johnson Road, Charleston, SC 29412, USA
| | - T. Gibson Gaylord
- Bozeman Fish Technology Center, United States Fish and Wildlife Service, 4050 Bridger Canyon Road, Bozeman, MT 59715, USA
| | - Daniel W. Bearden
- Marine Biochemical Sciences Group, Chemical Sciences Division, National Institute of Standards and Technology, Hollings Marine Laboratory, 331 Fort Johnson Road, Charleston, SC 29412, USA
| | - Michael R. Denson
- Marine Resources Research Institute, South Carolina Department of Natural Resources, 217 Fort Johnson Road, Charleston, SC 29412, USA
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SWATH-Based Comprehensive Determination of the Localization of Apical and Basolateral Membrane Proteins Using Mouse Liver as a Model Tissue. Biomedicines 2022; 10:biomedicines10020383. [PMID: 35203592 PMCID: PMC8962430 DOI: 10.3390/biomedicines10020383] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2021] [Revised: 02/03/2022] [Accepted: 02/03/2022] [Indexed: 12/01/2022] Open
Abstract
The purpose of this study was to develop a method to comprehensively determine the localization of apical and basolateral membrane proteins, using a combination of apical/basolateral membrane separation and accurate SWATH (Sequential Window Acquisition of all THeoretical fragment ion spectra) proteomics. The SWATH analysis of basolateral and apical plasma membrane fractions in mouse liver quantified the protein expression of 1373 proteins. The basolateral/apical ratios of the protein expression levels were compared with the reported immunohistochemical localization for 41 model proteins (23 basolateral, 11 apical and 7 both membrane-localized proteins). Three groups were perfectly distinguished. Border lines to distinguish the apical-, both- and basolateral localizations were determined to be 0.766 and 1.42 based on probability density. The method that was established was then applied to the comprehensive determination of the proteins in mouse liver. The findings indicated that 154 and 125 proteins were localized in the apical and basolateral membranes, respectively. The levels of receptors, CD antigens and integrins, enzymes and Ras-related molecules were much higher in apical membranes than in basolateral membranes. In contrast, the levels of adhesion molecules, scaffold proteins and transporters in basolateral membranes were much higher than in apical membranes.
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Upadhyay A, Boyle KE, Broderick TL. The Effects of Streptozotocin-Induced Diabetes and Insulin Treatment on Carnitine Biosynthesis and Renal Excretion. Molecules 2021; 26:6872. [PMID: 34833964 PMCID: PMC8620001 DOI: 10.3390/molecules26226872] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2021] [Revised: 11/09/2021] [Accepted: 11/10/2021] [Indexed: 11/16/2022] Open
Abstract
Carnitine insufficiency is reported in type 1 diabetes mellitus. To determine whether this is accompanied by defects in biosynthesis and/or renal uptake, liver and kidney were obtained from male Sprague-Dawley rats with streptozotocin-induced diabetes. Diabetic rats exhibited the metabolic consequences of type 1 diabetes, including hypoinsulinemia, hyperglycemia, and increased urine output. Systemic hypocarnitinemia, expressed as free carnitine levels, was evident in the plasma, liver, and kidney of diabetic rats. Compared to control rats, the low free carnitine in the plasma of diabetic rats was accompanied by decreased expression of γ-butyrobetaine hydroxylase in liver and kidney, suggesting impaired carnitine biosynthesis. Expression of organic cation transporter-2 in kidney was also reduced, indicating impaired renal reabsorption, and confirmed by the presence of elevated levels of free carnitine in the urine of diabetic rats. Insulin treatment of diabetic rats reversed the plasma hypocarnitinemia, increased the free carnitine content in both kidney and liver, and prevented urinary losses of free carnitine. This was associated with increased expression of γ-butyrobetaine hydroxylase and organic cation transporter-2. The results of our study indicate that type 1 diabetes induced with streptozotocin disrupts carnitine biosynthesis and renal uptake mechanisms, leading to carnitine insufficiency. These aberrations in carnitine homeostasis are prevented with daily insulin treatment.
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Affiliation(s)
- Aman Upadhyay
- Department of Biomedical Sciences, College of Graduate Studies, Midwestern University, Glendale, AZ 85308, USA;
| | - Kate E. Boyle
- Arizona College of Osteopathic Medicine, Midwestern University, Glendale, AZ 85308, USA;
| | - Tom L. Broderick
- Laboratory of Diabetes and Exercise Metabolism, Department of Physiology, College of Graduate Studies, Midwestern University, Glendale, AZ 85308, USA
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Sun D, Chen Q, Gai Z, Zhang F, Yang X, Hu W, Chen C, Yang G, Hörmann S, Kullak-Ublick GA, Visentin M. The Role of the Carnitine/Organic Cation Transporter Novel 2 in the Clinical Outcome of Patients With Locally Advanced Esophageal Carcinoma Treated With Oxaliplatin. Front Pharmacol 2021; 12:684545. [PMID: 34603016 PMCID: PMC8481660 DOI: 10.3389/fphar.2021.684545] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2021] [Accepted: 08/18/2021] [Indexed: 01/25/2023] Open
Abstract
Esophageal cancer is the ninth most common malignancy worldwide, ranking sixth in mortality. Platinum-based chemotherapy is commonly used for treating locally advanced esophageal cancer, yet it is ineffective in a large portion of patients. There is a need for reliable molecular markers with direct clinical application for a prospective selection of patients who can benefit from chemotherapy and patients in whom toxicity is likely to outweigh the benefit. The cytotoxic activity of platinum derivatives largely depends on the uptake and accumulation into cells, primarily by organic cation transporters (OCTs). The aim of the study was to investigate the impact of OCT expression on the clinical outcome of patients with esophageal cancer treated with oxaliplatin. Twenty patients with esophageal squamous cell carcinoma (SCC) were prospectively enrolled and surgical specimens used for screening OCT expression level by western blotting and/or immunostaining, and for culture of cancer cells. Sixty-seven patients with SCC who received oxaliplatin and for whom follow-up was available were retrospectively assessed for organic cation/carnitine transporter 2 (OCTN2) expression by real time RT-PCR and immunostaining. OCTN2 staining was also performed in 22 esophageal adenocarcinomas. OCTN2 function in patient-derived cancer cells was evaluated by assessing L-carnitine uptake and sensitivity to oxaliplatin. The impact of OCTN2 on oxaliplatin activity was also assessed in HEK293 cells overexpressing OCTN2. OCTN2 expression was higher in tumor than in normal tissues. In patient-derived cancer cells and HEK293 cells, the expression of OCTN2 sensitized to oxaliplatin. Patients treated with oxaliplatin who had high OCTN2 level in the tumor tissue had a reduced risk of recurrence and a longer survival time than those with low expression of OCTN2 in tumor tissue. In conclusion, OCTN2 is expressed in esophageal cancer and it is likely to contribute to the accumulation and cytotoxic activity of oxaliplatin in patients with esophageal carcinoma treated with oxaliplatin.
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Affiliation(s)
- Dongfeng Sun
- Department of Thoracic Surgery, The First Affiliated Hospital of Shandong First Medical University & Shandong Provincial Qianfoshan Hospital, Shandong Medicine and Health Key Laboratory of Emergency Medicine, Shandong Lung Cancer Institute, Shandong Institute of Respiratory Diseases, Jinan, China
| | - Qingfa Chen
- The Institute for Tissue Engineering and Regenerative Medicine, Liaocheng University/Liaocheng People's Hospital, Liaocheng, China
| | - Zhibo Gai
- Department of Clinical Pharmacology and Toxicology, University Hospital Zurich, University of Zurich, Zurich, Switzerland
| | - Fengxia Zhang
- Department of Thoracic Surgery, The First Affiliated Hospital of Shandong First Medical University & Shandong Provincial Qianfoshan Hospital, Shandong Medicine and Health Key Laboratory of Emergency Medicine, Shandong Lung Cancer Institute, Shandong Institute of Respiratory Diseases, Jinan, China
| | - Xiaoqing Yang
- Department of Pathology, The First Affiliated Hospital of Shandong First Medical University and Shandong Provincial Qianfoshan Hospital, Jinan, China
| | - Wensi Hu
- Department of Thoracic Surgery, The First Affiliated Hospital of Shandong First Medical University & Shandong Provincial Qianfoshan Hospital, Shandong Medicine and Health Key Laboratory of Emergency Medicine, Shandong Lung Cancer Institute, Shandong Institute of Respiratory Diseases, Jinan, China
| | - Chengyu Chen
- Department of Thoracic Surgery, The First Affiliated Hospital of Shandong First Medical University & Shandong Provincial Qianfoshan Hospital, Shandong Medicine and Health Key Laboratory of Emergency Medicine, Shandong Lung Cancer Institute, Shandong Institute of Respiratory Diseases, Jinan, China
| | - Guangjie Yang
- Department of Nuclear Medicine, The Affiliated Hospital of Qingdao University, Qingdao, Shandong, China
| | - Severin Hörmann
- Department of Pathology and Molecular Pathology, University Hospital Zurich, University of Zurich, Zurich, Switzerland
| | - Gerd A Kullak-Ublick
- Department of Clinical Pharmacology and Toxicology, University Hospital Zurich, University of Zurich, Zurich, Switzerland
| | - Michele Visentin
- Department of Clinical Pharmacology and Toxicology, University Hospital Zurich, University of Zurich, Zurich, Switzerland
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Zhang L, Gui T, Console L, Scalise M, Indiveri C, Hausler S, Kullak-Ublick GA, Gai Z, Visentin M. Cholesterol stimulates the cellular uptake of L-carnitine by the carnitine/organic cation transporter novel 2 (OCTN2). J Biol Chem 2020; 296:100204. [PMID: 33334877 PMCID: PMC7948396 DOI: 10.1074/jbc.ra120.015175] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2020] [Revised: 12/14/2020] [Accepted: 12/17/2020] [Indexed: 12/19/2022] Open
Abstract
The carnitine/organic cation transporter novel 2 (OCTN2) is responsible for the cellular uptake of carnitine in most tissues. Being a transmembrane protein OCTN2 must interact with the surrounding lipid microenvironment to function. Among the main lipid species that constitute eukaryotic cells, cholesterol has highly dynamic levels under a number of physiopathological conditions. This work describes how plasma membrane cholesterol modulates OCTN2 transport of L-carnitine in human embryonic kidney 293 cells overexpressing OCTN2 (OCTN2-HEK293) and in proteoliposomes harboring human OCTN2. We manipulated the cholesterol content of intact cells, assessed by thin layer chromatography, through short exposures to empty and/or cholesterol-saturated methyl-β-cyclodextrin (mβcd), whereas free cholesterol was used to enrich reconstituted proteoliposomes. We measured OCTN2 transport using [3H]L-carnitine, and expression levels and localization by surface biotinylation and Western blotting. A 20-min preincubation with mβcd reduced the cellular cholesterol content and inhibited L-carnitine influx by 50% in comparison with controls. Analogously, the insertion of cholesterol in OCTN2-proteoliposomes stimulated L-carnitine uptake in a dose-dependent manner. Carnitine uptake in cells incubated with empty mβcd and cholesterol-saturated mβcd to preserve the cholesterol content was comparable with controls, suggesting that the mβcd effect on OCTN2 was cholesterol dependent. Cholesterol stimulated L-carnitine influx in cells by markedly increasing the affinity for L-carnitine and in proteoliposomes by significantly enhancing the affinity for Na+ and, in turn, the L-carnitine maximal transport capacity. Because of the antilipogenic and antioxidant features of L-carnitine, the stimulatory effect of cholesterol on L-carnitine uptake might represent a novel protective effect against lipid-induced toxicity and oxidative stress.
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Affiliation(s)
- Lu Zhang
- College of Traditional Chinese Medicine, Innovation Research Institute of Traditional Chinese Medicine, Shandong University of Traditional Chinese Medicine, Jinan, China; Department of Clinical Pharmacology and Toxicology, University Hospital Zurich, University of Zurich, Zurich, Switzerland
| | - Ting Gui
- College of Traditional Chinese Medicine, Innovation Research Institute of Traditional Chinese Medicine, Shandong University of Traditional Chinese Medicine, Jinan, China
| | - Lara Console
- Department DiBEST (Biologia, Ecologia, Scienze della Terra) Unit of Biochemistry and Molecular Biotechnology, University of Calabria, Arcavacata di Rende, Italy
| | - Mariafrancesca Scalise
- Department DiBEST (Biologia, Ecologia, Scienze della Terra) Unit of Biochemistry and Molecular Biotechnology, University of Calabria, Arcavacata di Rende, Italy
| | - Cesare Indiveri
- Department DiBEST (Biologia, Ecologia, Scienze della Terra) Unit of Biochemistry and Molecular Biotechnology, University of Calabria, Arcavacata di Rende, Italy
| | - Stephanie Hausler
- Department of Clinical Pharmacology and Toxicology, University Hospital Zurich, University of Zurich, Zurich, Switzerland
| | - Gerd A Kullak-Ublick
- Department of Clinical Pharmacology and Toxicology, University Hospital Zurich, University of Zurich, Zurich, Switzerland; Mechanistic Safety, CMO & Patient Safety, Global Drug Development, Novartis Pharma, Basel, Switzerland
| | - Zhibo Gai
- College of Traditional Chinese Medicine, Innovation Research Institute of Traditional Chinese Medicine, Shandong University of Traditional Chinese Medicine, Jinan, China; Department of Clinical Pharmacology and Toxicology, University Hospital Zurich, University of Zurich, Zurich, Switzerland.
| | - Michele Visentin
- Department of Clinical Pharmacology and Toxicology, University Hospital Zurich, University of Zurich, Zurich, Switzerland.
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Organic Cation Transporters in Human Physiology, Pharmacology, and Toxicology. Int J Mol Sci 2020; 21:ijms21217890. [PMID: 33114309 PMCID: PMC7660683 DOI: 10.3390/ijms21217890] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2020] [Revised: 10/20/2020] [Accepted: 10/21/2020] [Indexed: 12/13/2022] Open
Abstract
Individual cells and epithelia control the chemical exchange with the surrounding environment by the fine-tuned expression, localization, and function of an array of transmembrane proteins that dictate the selective permeability of the lipid bilayer to small molecules, as actual gatekeepers to the interface with the extracellular space. Among the variety of channels, transporters, and pumps that localize to cell membrane, organic cation transporters (OCTs) are considered to be extremely relevant in the transport across the plasma membrane of the majority of the endogenous substances and drugs that are positively charged near or at physiological pH. In humans, the following six organic cation transporters have been characterized in regards to their respective substrates, all belonging to the solute carrier 22 (SLC22) family: the organic cation transporters 1, 2, and 3 (OCT1–3); the organic cation/carnitine transporter novel 1 and 2 (OCTN1 and N2); and the organic cation transporter 6 (OCT6). OCTs are highly expressed on the plasma membrane of polarized epithelia, thus, playing a key role in intestinal absorption and renal reabsorption of nutrients (e.g., choline and carnitine), in the elimination of waste products (e.g., trimethylamine and trimethylamine N-oxide), and in the kinetic profile and therapeutic index of several drugs (e.g., metformin and platinum derivatives). As part of the Special Issue Physiology, Biochemistry, and Pharmacology of Transporters for Organic Cations, this article critically presents the physio-pathological, pharmacological, and toxicological roles of OCTs in the tissues in which they are primarily expressed.
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Ranea-Robles P, Yu C, van Vlies N, Vaz FM, Houten SM. Slc22a5 haploinsufficiency does not aggravate the phenotype of the long-chain acyl-CoA dehydrogenase KO mouse. J Inherit Metab Dis 2020; 43:486-495. [PMID: 31845336 PMCID: PMC7205564 DOI: 10.1002/jimd.12204] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/12/2019] [Revised: 11/22/2019] [Accepted: 12/11/2019] [Indexed: 01/10/2023]
Abstract
Secondary carnitine deficiency is commonly observed in inherited metabolic diseases characterised by the accumulation of acylcarnitines such as mitochondrial fatty acid oxidation (FAO) disorders. It is currently unclear if carnitine deficiency and/or acylcarnitine accumulation play a role in the pathophysiology of FAO disorders. The long-chain acyl-CoA dehydrogenase (LCAD) KO mouse is a model for long-chain FAO disorders and is characterised by decreased levels of tissue and plasma free carnitine. Tissue levels of carnitine are controlled by SLC22A5, the plasmalemmal carnitine transporter. Here, we have further decreased carnitine availability in the LCAD KO mouse through a genetic intervention by introducing one defective Slc22a5 allele (jvs). Slc22a5 haploinsufficiency decreased free carnitine levels in liver, kidney, and heart of LCAD KO animals. The resulting decrease in the tissue long-chain acylcarnitines levels had a similar magnitude as the decrease in free carnitine. Levels of cardiac deoxycarnitine, a carnitine biosynthesis intermediate, were elevated due to Slc22a5 haploinsufficiency in LCAD KO mice. A similar increase in heart and muscle deoxycarnitine was observed in an independent experiment using Slc22a5jvs/jvs mice. Cardiac hypertrophy, fasting-induced hypoglycemia and increased liver weight, the major phenotypes of the LCAD KO mouse, were not affected by Slc22a5 haploinsufficiency. This may suggest that secondary carnitine deficiency does not play a major role in the pathophysiology of these phenotypes. Similarly, our data do not support a major role for toxicity of long-chain acylcarnitines in the phenotype of the LCAD KO mouse.
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Affiliation(s)
- Pablo Ranea-Robles
- Department of Genetics and Genomic Sciences, Icahn Institute for Data Science and Genomic Technology, Icahn School of Medicine at Mount Sinai, New York, New York
| | - Chunli Yu
- Department of Genetics and Genomic Sciences, Icahn Institute for Data Science and Genomic Technology, Icahn School of Medicine at Mount Sinai, New York, New York
- Mount Sinai Genomics, Inc., New York, New York
| | - Naomi van Vlies
- Institute for Translational Vaccinology, Bilthoven, The Netherlands
- Department of Clinical Chemistry, Amsterdam Gastroenterology & Metabolism, Laboratory Genetic Metabolic Diseases, Amsterdam UMC, University of Amsterdam, Amsterdam, The Netherlands
| | - Frédéric M Vaz
- Department of Clinical Chemistry, Amsterdam Gastroenterology & Metabolism, Laboratory Genetic Metabolic Diseases, Amsterdam UMC, University of Amsterdam, Amsterdam, The Netherlands
| | - Sander M Houten
- Department of Genetics and Genomic Sciences, Icahn Institute for Data Science and Genomic Technology, Icahn School of Medicine at Mount Sinai, New York, New York
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Pochini L, Galluccio M, Scalise M, Console L, Indiveri C. OCTN: A Small Transporter Subfamily with Great Relevance to Human Pathophysiology, Drug Discovery, and Diagnostics. SLAS DISCOVERY 2018; 24:89-110. [PMID: 30523710 DOI: 10.1177/2472555218812821] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
OCTN is a small subfamily of membrane transport proteins that belongs to the larger SLC22 family. Two of the three members of the subfamily, namely, OCTN2 and OCTN1, are present in humans. OCTN2 plays a crucial role in the absorption of carnitine from diet and in its distribution to tissues, as demonstrated by the occurrence of severe pathologies caused by malfunctioning or altered expression of this transporter. These findings suggest avoiding a strict vegetarian diet during pregnancy and in childhood. Other roles of OCTN2 are related to the traffic of carnitine derivatives in many tissues. The role of OCTN1 is still unclear, despite the identification of some substrates such as ergothioneine, acetylcholine, and choline. Plausibly, the transporter acts on the control of inflammation and oxidative stress, even though knockout mice do not display phenotypes. A clear role of both transporters has been revealed in drug interaction and delivery. The polyspecificity of the OCTNs is at the base of the interactions with drugs. Interestingly, OCTN2 has been recently exploited in the prodrug approach and in diagnostics. A promising application derives from the localization of OCTN2 in exosomes that represent a noninvasive diagnostic tool.
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Affiliation(s)
- Lorena Pochini
- 1 Department DiBEST (Biologia, Ecologia, Scienze della Terra), Unit of Biochemistry and Molecular Biotechnology, University of Calabria, Arcavacata di Rende, Italy
| | - Michele Galluccio
- 1 Department DiBEST (Biologia, Ecologia, Scienze della Terra), Unit of Biochemistry and Molecular Biotechnology, University of Calabria, Arcavacata di Rende, Italy
| | - Mariafrancesca Scalise
- 1 Department DiBEST (Biologia, Ecologia, Scienze della Terra), Unit of Biochemistry and Molecular Biotechnology, University of Calabria, Arcavacata di Rende, Italy
| | - Lara Console
- 1 Department DiBEST (Biologia, Ecologia, Scienze della Terra), Unit of Biochemistry and Molecular Biotechnology, University of Calabria, Arcavacata di Rende, Italy
| | - Cesare Indiveri
- 1 Department DiBEST (Biologia, Ecologia, Scienze della Terra), Unit of Biochemistry and Molecular Biotechnology, University of Calabria, Arcavacata di Rende, Italy.,2 CNR Institute of Biomembranes, Bioenergetics and Molecular Biotechnology, Bari, Italy
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Kou L, Sun R, Ganapathy V, Yao Q, Chen R. Recent advances in drug delivery via the organic cation/carnitine transporter 2 (OCTN2/SLC22A5). Expert Opin Ther Targets 2018; 22:715-726. [PMID: 30016594 DOI: 10.1080/14728222.2018.1502273] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
INTRODUCTION Transporters in the plasma membrane have been exploited successfully for the delivery of drugs in the form of prodrugs and nanoparticles. Organic cation/carnitine transporter 2 (OCTN2, SLC22A5) has emerged as a viable target for drug delivery. OCTN2 is a Na+-dependent high-affinity transporter for L-carnitine and a Na+-independent transporter for organic cations. OCTN2 is expressed in the blood-brain barrier, heart, liver, kidney, intestinal tract and placenta and plays an essential role in L-carnitine homeostasis in the body. Areas covered: In recent years, several studies have been reported in the literature describing the utility of OCTN2 to enhance the delivery of drugs, prodrugs and nanoparticles. Here we summarize the salient features of OCTN2 in terms of its role in the cellular uptake of its physiological substrate L-carnitine in physiological and pathological context; the structural requirements for recognition and the recent advances in OCTN2-targeted drug delivery systems, including prodrugs and nanoparticles, are discussed. Expert opinion: This transporter has great potential to be utilized as a target for drug delivery to improve oral absorption of drugs in the intestinal tract. It also has potential to facilitate the transfer of drugs across the biological barriers such as the blood-brain barrier, blood-retinal barrier, and maternal-fetal barrier.
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Affiliation(s)
- Longfa Kou
- a Department of Pharmacy , The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University , Wenzhou , China
| | - Rui Sun
- a Department of Pharmacy , The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University , Wenzhou , China
| | - Vadivel Ganapathy
- a Department of Pharmacy , The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University , Wenzhou , China.,b Department of Cell Biology and Biochemistry , School of Medicine, Texas Tech University Health Sciences Center , Lubbock , TX , USA
| | - Qing Yao
- c School of Pharmaceutical Sciences , Wenzhou Medical University , Wenzhou , China
| | - Ruijie Chen
- a Department of Pharmacy , The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University , Wenzhou , China
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Kubo Y, Akanuma SI, Hosoya KI. Impact of SLC6A Transporters in Physiological Taurine Transport at the Blood-Retinal Barrier and in the Liver. Biol Pharm Bull 2017; 39:1903-1911. [PMID: 27904033 DOI: 10.1248/bpb.b16-00597] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Cumulative studies showed that taurine (2-aminoethanesulfonic acid) contributes to a variety of physiological events. Transport study suggested the cellular taurine transport in an Na+- and Cl--dependent manner, and the several members of SLC6A family have been shown as taurine transporter. At the inner blood-retinal barrier (BRB), taurine transporter (TauT/SLC6A) is involved in the transport of taurine to the retina from the circulating blood. The involvement of TauT is also suggested in γ-aminobutyric acid (GABA) transport at the inner BRB, and its role is assumed in the elimination of GABA from the retinal interstitial fluid. In the retina, taurine is thought to be a major organic osmolyte, and its influx and efflux through TauT and volume-sensitive organic osmolyte and anion channel (VSOAC) in Müller cells regulate the osmolarity in the retinal microenvironment to maintain a healthy retina. In the liver, hepatocytes take up taurine via GABA transporter 2 (GAT2/SLC6A13, the orthologue of mouse GAT3) expressed at the sinusoidal membrane of periportal hepatocytes, contributing to the metabolism of bile acid. Site-directed mutagenesis study suggests amino acid residues that are crucial in the recognition of substrates by GATs and TauT. The evidence suggests the physiological impact of taurine transporters in tissues.
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Affiliation(s)
- Yoshiyuki Kubo
- Department of Pharmaceutics, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama
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Schmitt S, Höfner G, Wanner KT. MS Transport Assays for γ-Aminobutyric Acid Transporters—An Efficient Alternative for Radiometric Assays. Anal Chem 2014; 86:7575-83. [DOI: 10.1021/ac501366r] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Affiliation(s)
- Sebastian Schmitt
- Department of Pharmacy—Center
for Drug Research, Ludwig-Maximilians-Universität München, Butenandtstraße
7, 81377 München, Germany
| | - Georg Höfner
- Department of Pharmacy—Center
for Drug Research, Ludwig-Maximilians-Universität München, Butenandtstraße
7, 81377 München, Germany
| | - Klaus T. Wanner
- Department of Pharmacy—Center
for Drug Research, Ludwig-Maximilians-Universität München, Butenandtstraße
7, 81377 München, Germany
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Tamai I. Pharmacological and pathophysiological roles of carnitine/organic cation transporters (OCTNs: SLC22A4, SLC22A5 and Slc22a21). Biopharm Drug Dispos 2012; 34:29-44. [PMID: 22952014 DOI: 10.1002/bdd.1816] [Citation(s) in RCA: 99] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2012] [Revised: 08/27/2012] [Accepted: 08/30/2012] [Indexed: 02/06/2023]
Abstract
The carnitine/organic cation transporter (OCTN) family consists of three transporter isoforms, i.e. OCTN1 (SLC22A4) and OCTN2 (SLC22A5) in humans and animals and Octn3 (Slc22a21) in mice. These transporters are physiologically essential to maintain appropriate systemic and tissue concentrations of carnitine by regulating its membrane transport during intestinal absorption, tissue distribution and renal reabsorption. Among them, OCTN2 is a sodium-dependent, high-affinity transporter of carnitine, and a functional defect of OCTN2 due to genetic mutation causes primary systemic carnitine deficiency (SCD). Since carnitine is essential for beta-oxidation of long-chain fatty acids to produce ATP, OCTN2 gene mutation causes a range of symptoms, including cardiomyopathy, skeletal muscle weakness, fatty liver and male infertility. These functional consequences of Octn2 gene mutation can be seen clearly in an animal model, jvs mouse, which exhibits the SCD phenotype. In addition, although the mechanism is not clear, single nucleotide polymorphisms of OCTN1 and OCTN2 genes are associated with increased incidences of rheumatoid arthritis, Crohn's disease and asthma. OCTN1 and OCTN2 accept cationic drugs as substrates and contribute to intestinal and pulmonary absorption, tissue distribution (including to tumour cells), and renal excretion of these drugs. Modulation of the transport activity of OCTN2 by externally administered drugs may cause drug-induced secondary carnitine deficiency. Rodent Octn3 transports carnitine specifically, particularly in male reproductive tissues. Thus, the OCTNs are physiologically, pathologically and pharmacologically important. Detailed characterization of these transporters will greatly improve our understanding of the pathology associated with common diseases caused by functional deficiency of OCTNs.
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Affiliation(s)
- Ikumi Tamai
- Faculty of Pharmaceutical Sciences, Institute of Medical, Pharmaceutical and Health Sciences, Kanazawa University, Kanazawa, 920-1192, Japan.
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Ikeda S, Tachikawa M, Akanuma SI, Fujinawa J, Hosoya KI. Involvement of γ-aminobutyric acid transporter 2 in the hepatic uptake of taurine in rats. Am J Physiol Gastrointest Liver Physiol 2012; 303:G291-7. [PMID: 22678999 DOI: 10.1152/ajpgi.00388.2011] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Taurine is essential for the hepatic synthesis of bile salts and, although taurine is synthesized mainly in pericentral hepatocytes, taurine and taurine-conjugated bile acids are abundant in periportal hepatocytes. One possible explanation for this discrepancy is that the active supply of taurine to hepatocytes from the blood stream is a key regulatory factor. The purpose of the present study is to investigate and identify the transporter responsible for taurine uptake by periportal hepatocytes. An in vivo bolus injection of [(3)H]taurine into the rat portal vein demonstrated that 25% of the injected [(3)H]taurine was taken up by the liver on a single pass. The in vivo uptake was significantly inhibited by GABA, taurine, β-alanine, and nipecotic acid, a GABA transporter (GAT) inhibitor, each at a concentration of 10 mM. The characteristics of Na(+)- and Cl(-)-dependent [(3)H]taurine uptake by freshly isolated rat hepatocytes were consistent with those of GAT2 (solute carrier SLC6A13). Indeed, the K(m) value of the saturable uptake (594 μM) was close to that of mouse SLC6A13-mediated taurine transport. Although GABA, taurine, and β-alanine inhibited the [(3)H]taurine uptake by > 50%, each at a concentration of 10 mM, GABA caused a marked inhibition with an IC(50) value of 95 μM. The [(3)H]taurine uptake exhibited a significant reduction when the GAT2 gene was silenced. Immunohistochemical analysis showed that GAT2 was localized on the sinusoidal membrane of the hepatocytes predominantly in the periportal region. These results suggest that GAT2 is responsible for taurine transport from the circulating blood to hepatocytes predominantly in the periportal region.
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Affiliation(s)
- Saori Ikeda
- Department of Pharmaceutics, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama, Japan
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A common X-linked inborn error of carnitine biosynthesis may be a risk factor for nondysmorphic autism. Proc Natl Acad Sci U S A 2012; 109:7974-81. [PMID: 22566635 DOI: 10.1073/pnas.1120210109] [Citation(s) in RCA: 91] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
We recently reported a deletion of exon 2 of the trimethyllysine hydroxylase epsilon (TMLHE) gene in a proband with autism. TMLHE maps to the X chromosome and encodes the first enzyme in carnitine biosynthesis, 6-N-trimethyllysine dioxygenase. Deletion of exon 2 of TMLHE causes enzyme deficiency, resulting in increased substrate concentration (6-N-trimethyllysine) and decreased product levels (3-hydroxy-6-N-trimethyllysine and γ-butyrobetaine) in plasma and urine. TMLHE deficiency is common in control males (24 in 8,787 or 1 in 366) and was not significantly increased in frequency in probands from simplex autism families (9 in 2,904 or 1 in 323). However, it was 2.82-fold more frequent in probands from male-male multiplex autism families compared with controls (7 in 909 or 1 in 130; P = 0.023). Additionally, six of seven autistic male siblings of probands in male-male multiplex families had the deletion, suggesting that TMLHE deficiency is a risk factor for autism (metaanalysis Z-score = 2.90 and P = 0.0037), although with low penetrance (2-4%). These data suggest that dysregulation of carnitine metabolism may be important in nondysmorphic autism; that abnormalities of carnitine intake, loss, transport, or synthesis may be important in a larger fraction of nondysmorphic autism cases; and that the carnitine pathway may provide a novel target for therapy or prevention of autism.
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Tachikawa M, Ikeda S, Fujinawa J, Hirose S, Akanuma SI, Hosoya KI. γ-Aminobutyric acid transporter 2 mediates the hepatic uptake of guanidinoacetate, the creatine biosynthetic precursor, in rats. PLoS One 2012; 7:e32557. [PMID: 22384273 PMCID: PMC3288109 DOI: 10.1371/journal.pone.0032557] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2011] [Accepted: 02/01/2012] [Indexed: 12/14/2022] Open
Abstract
Guanidinoacetic acid (GAA) is the biosynthetic precursor of creatine which is involved in storage and transmission of phosphate-bound energy. Hepatocytes readily convert GAA to creatine, raising the possibility that the active uptake of GAA by hepatocytes is a regulatory factor. The purpose of this study is to investigate and identify the transporter responsible for GAA uptake by hepatocytes. The characteristics of [(14)C]GAA uptake by hepatocytes were elucidated using the in vivo liver uptake method, freshly isolated rat hepatocytes, an expression system of Xenopus laevis oocytes, gene knockdown, and an immunohistochemical technique. In vivo injection of [(14)C]GAA into the rat femoral vein and portal vein results in the rapid uptake of [(14)C]GAA by the liver. The uptake was markedly inhibited by γ-aminobutyric acid (GABA) and nipecotinic acid, an inhibitor of GABA transporters (GATs). The characteristics of Na(+)- and Cl(-)-dependent [(14)C]GAA uptake by freshly isolated rat hepatocytes were consistent with those of GAT2. The Km value of the GAA uptake (134 µM) was close to that of GAT2-mediated GAA transport (78.9 µM). GABA caused a marked inhibition with an IC(50) value of 8.81 µM. The [(14)C]GAA uptake exhibited a significant reduction corresponding to the reduction in GAT2 protein expression. GAT2 was localized on the sinusoidal membrane of the hepatocytes predominantly in the periportal region. This distribution pattern was consistent with that of the creatine biosynthetic enzyme, S-adenosylmethionine:guanidinoacetate N-methyltransferase. GAT2 makes a major contribution to the sinusoidal GAA uptake by periportal hepatocytes, thus regulating creatine biosynthesis in the liver.
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Affiliation(s)
- Masanori Tachikawa
- Department of Pharmaceutics, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama, Japan
- Division of Membrane Transport and Drug Targeting, Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai, Japan
| | - Saori Ikeda
- Department of Pharmaceutics, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama, Japan
| | - Jun Fujinawa
- Department of Pharmaceutics, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama, Japan
| | - Shirou Hirose
- Department of Pharmaceutics, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama, Japan
| | - Shin-ichi Akanuma
- Department of Pharmaceutics, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama, Japan
| | - Ken-ichi Hosoya
- Department of Pharmaceutics, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama, Japan
- * E-mail:
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Zhou Y, Holmseth S, Hua R, Lehre AC, Olofsson AM, Poblete-Naredo I, Kempson SA, Danbolt NC. The betaine-GABA transporter (BGT1, slc6a12) is predominantly expressed in the liver and at lower levels in the kidneys and at the brain surface. Am J Physiol Renal Physiol 2012; 302:F316-28. [DOI: 10.1152/ajprenal.00464.2011] [Citation(s) in RCA: 97] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
The Na+- and Cl−-dependent GABA-betaine transporter (BGT1) has received attention mostly as a protector against osmolarity changes in the kidney and as a potential controller of the neurotransmitter GABA in the brain. Nevertheless, the cellular distribution of BGT1, and its physiological importance, is not fully understood. Here we have quantified mRNA levels using TaqMan real-time PCR, produced a number of BGT1 antibodies, and used these to study BGT1 distribution in mice. BGT1 (protein and mRNA) is predominantly expressed in the liver (sinusoidal hepatocyte plasma membranes) and not in the endothelium. BGT1 is also present in the renal medulla, where it localizes to the basolateral membranes of collecting ducts (particularly at the papilla tip) and the thick ascending limbs of Henle. There is some BGT1 in the leptomeninges, but brain parenchyma, brain blood vessels, ependymal cells, the renal cortex, and the intestine are virtually BGT1 deficient in 1- to 3-mo-old mice. Labeling specificity was assured by processing tissue from BGT1-deficient littermates in parallel as negative controls. Addition of 2.5% sodium chloride to the drinking water for 48 h induced a two- to threefold upregulation of BGT1, tonicity-responsive enhancer binding protein, and sodium- myo-inositol cotransporter 1 (slc5a3) in the renal medulla, but not in the brain and barely in the liver. BGT1-deficient and wild-type mice appeared to tolerate the salt treatment equally well, possibly because betaine is one of several osmolytes. In conclusion, this study suggests that BGT1 plays its main role in the liver, thereby complementing other betaine-transporting carrier proteins (e.g., slc6a20) that are predominantly expressed in the small intestine or kidney rather than the liver.
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Affiliation(s)
- Y. Zhou
- Department of Anatomy, Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway
| | - S. Holmseth
- Department of Anatomy, Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway
| | - R. Hua
- Department of Anatomy, Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway
| | - A. C. Lehre
- Department of Anatomy, Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway
| | - A. M. Olofsson
- Department of Anatomy, Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway
| | - I. Poblete-Naredo
- Departamento de Genética y Biología Molecular, Centro de Investigación y de studios Avanzados del Instituto Politécnico Nacional, México City, Mexico; and
| | - S. A. Kempson
- Department of Cellular and Integrative Physiology, Indiana University School of Medicine, Indianapolis, Indiana
| | - N. C. Danbolt
- Department of Anatomy, Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway
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Jong NN, Nakanishi T, Liu JJ, Tamai I, McKeage MJ. Oxaliplatin transport mediated by organic cation/carnitine transporters OCTN1 and OCTN2 in overexpressing human embryonic kidney 293 cells and rat dorsal root ganglion neurons. J Pharmacol Exp Ther 2011; 338:537-47. [PMID: 21606177 DOI: 10.1124/jpet.111.181297] [Citation(s) in RCA: 101] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
The organic cation/carnitine transporters OCTN1 and OCTN2 are related to other organic cation transporters (OCT1, OCT2, and OCT3) known for transporting oxaliplatin, an anticancer drug with dose-limiting neurotoxicity. In this study, we sought to determine whether OCTN1 and OCTN2 also transported oxaliplatin and to characterize their functional expression and contributions to its neuronal accumulation and neurotoxicity in dorsal root ganglion (DRG) neurons relative to those of OCTs. [(14)C]Oxaliplatin uptake, platinum accumulation, and cytotoxicity were determined in OCTN-overexpressing human embryonic kidney (HEK) 293 cells and primary cultures of rat DRG neurons. Levels of mRNA and functional activities of rat (r)Octns and rOcts in rat DRG tissue and primary cultures were characterized using reverse transcription-polymerase chain reaction and uptake of model OCT/OCTN substrates, including [(3)H]1-methyl-4-phenylpyridinium (MPP(+)) (OCT1-3), [(14)C]tetraethylammonium bromide (TEA(+)) (OCT1-3 and OCTN1/2), [(3)H]ergothioneine (OCTN1), and [(3)H]l-carnitine (OCTN2). HEK293 cells overexpressing rOctn1, rOctn2, human OCTN1, and human OCTN2 showed increased uptake and cytotoxicity of oxaliplatin compared with mock-transfected HEK293 controls; in addition, both uptake and cytotoxicity were inhibited by ergothioneine and L-carnitine. The uptake of ergothioneine mediated by OCTN1 and of L-carnitine mediated by OCTN2 was decreased during oxaliplatin exposure. rOctn1 and rOctn2 mRNA was readily detected in rat DRG tissue, and they were functionally active in cultured rat DRG neurons, more so than rOct1, rOct2, or rOct3. DRG neuronal accumulation of [(14)C]oxaliplatin and platinum during oxaliplatin exposure depended on time, concentration, temperature, and sodium and was inhibited by ergothioneine and to a lesser extent by L-carnitine but not by MPP(+). Loss of DRG neuronal viability during oxaliplatin exposure was inhibited by ergothioneine but not by L-carnitine or MPP(+). OCTN1 and OCTN2 both transport oxaliplatin and are functionally expressed by DRG neurons. OCTN1-mediated transport of oxaliplatin appears to contribute to its neuronal accumulation and treatment-limiting neurotoxicity more so than OCTN2 or OCTs.
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Affiliation(s)
- Nancy N Jong
- Cancer Clinical Pharmacology Research Group, Department of Pharmacology and Clinical Pharmacology, School of Medical Sciences, University of Auckland, 85 Park Rd., Grafton, Private Bag 92019, Auckland 1023, New Zealand
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Lemire J, Mailloux R, Darwich R, Auger C, Appanna VD. The disruption of L-carnitine metabolism by aluminum toxicity and oxidative stress promotes dyslipidemia in human astrocytic and hepatic cells. Toxicol Lett 2011; 203:219-26. [PMID: 21439360 DOI: 10.1016/j.toxlet.2011.03.019] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2011] [Revised: 03/11/2011] [Accepted: 03/14/2011] [Indexed: 12/19/2022]
Abstract
L-Carnitine is a critical metabolite indispensable for the metabolism of lipids as it facilitates fatty acid transport into the mitochondrion where β-oxidation occurs. Human astrocytes (CCF-STTG1 cells) and hepatocytes (HepG2 cells) exposed to aluminum (Al) and hydrogen peroxide (H₂O₂), were characterized with lower levels of L-carnitine, diminished β-oxidation, and increased lipid accumulation compared to the controls. γ-Butyrobetainealdehyde dehydrogenase (BADH) and butyrobetaine dioxygenase (BBDOX), two key enzymes mediating the biogenesis of L-carnitine, were sharply reduced during Al and H₂O₂ challenge. Exposure of the Al and H₂O₂-treated cells to α-ketoglutarate (KG), led to the recovery of L-carnitine production with the concomitant reduction in ROS levels. It appears that the channeling of KG to combat oxidative stress results in decreased L-carnitine synthesis, an event that contributes to the dyslipidemia observed during Al and H₂O₂ insults in these mammalian cells. Hence, KG may help alleviate pathological conditions induced by oxidative stress.
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Affiliation(s)
- Joseph Lemire
- Department of Chemistry and Biochemistry, Laurentian University, Sudbury, Ontario P3E2C6, Canada
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Nakanishi T, Fukuyama Y, Fujita M, Shirasaka Y, Tamai I. Carnitine Precursor γ-Butyrobetaine is a Novel Substrate of the Na+- and Cl−-dependent GABA Transporter Gat2. Drug Metab Pharmacokinet 2011; 26:632-6. [DOI: 10.2133/dmpk.dmpk-11-nt-053] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Alshabanah OA, Hafez MM, Al-Harbi MM, Hassan ZK, Al Rejaie SS, Asiri YA, Sayed-Ahmed MM. Doxorubicin toxicity can be ameliorated during antioxidant L-carnitine supplementation. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2010; 3:428-33. [PMID: 21307642 PMCID: PMC3154045 DOI: 10.4161/oxim.3.6.14416] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Doxorubicin is an antibiotic broadly used in treatment of different types of solid tumors. The present study investigates whether L-carnitine, antioxidant agent, can reduce the hepatic damage induced by doxorubicin. Male Wistar albino rats were divided into six groups: group 1 was intraperitoneal injected with normal saline for 10 consecutive days; group 2, 3 and 4 were injected every other day with doxorubicin (3 mg/kg, i.p.), to obtain treatments with cumulative doses of 6, 12 and 18 mg/kg. The fifth group was injected with L-carnitine (200 mg/kg, i.p.) for 10 consecutive days and the sixth group was received doxorubicin (18 mg/kg) and L-carnitine (200 mg/kg). High cumulative dose of doxorubicin (18 mg/kg) significantly increases the biochemical levels of alanine transaminase, alkaline phosphatase, total bilirubin, thiobarbituric acid reactive substances (TBARs), total nitrate/nitrite (NOx) p < 0.05 and decrease in glutathione (GSH ), superoxide dismutase (SOD), glutathione peroxidase (GSHP x), glutathione-s-transferase (GST), glutathione reductase (GR) and catalase (CAT) activity p < 0.05. The effect of doxorubicin on the activity of antioxidant genes was confirmed by real time PCR in which the expression levels of these genes in liver tissue were significantly decrease compared to control p < 0.05. Interestingly, L-carnitine supplementation completely reversed the biochemical and gene expression levels induced by doxorubicin to the control values. In conclusion, data from this study suggest that the reduction of antioxidant defense during doxorubicin administration resulted in hepatic injury could be prevented by L-carnitine supplementation by decreasing the oxidative stress and preserving both the activity and gene expression level of antioxidant enzymes.
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Affiliation(s)
- Othman A Alshabanah
- Department of Pharmacology; College of pharmacy, King Saud University, Riyadh Kingdom of Saudi Arabia.
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