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Schmidt T, Meller S, Talbot SR, Berk BA, Law TH, Hobbs SL, Meyerhoff N, Packer RMA, Volk HA. Urinary Neurotransmitter Patterns Are Altered in Canine Epilepsy. Front Vet Sci 2022; 9:893013. [PMID: 35651965 PMCID: PMC9150448 DOI: 10.3389/fvets.2022.893013] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2022] [Accepted: 04/22/2022] [Indexed: 12/12/2022] Open
Abstract
Epilepsy is the most common chronic neurological disease in humans and dogs. Epilepsy is thought to be caused by an imbalance of excitatory and inhibitory neurotransmission. Intact neurotransmitters are transported from the central nervous system to the periphery, from where they are subsequently excreted through the urine. In human medicine, non-invasive urinary neurotransmitter analysis is used to manage psychological diseases, but not as yet for epilepsy. The current study aimed to investigate if urinary neurotransmitter profiles differ between dogs with epilepsy and healthy controls. A total of 223 urine samples were analysed from 63 dogs diagnosed with idiopathic epilepsy and 127 control dogs without epilepsy. The quantification of nine urinary neurotransmitters was performed utilising mass spectrometry technology. A significant difference between urinary neurotransmitter levels (glycine, serotonin, norepinephrine/epinephrine ratio, ɤ-aminobutyric acid/glutamate ratio) of dogs diagnosed with idiopathic epilepsy and the control group was found, when sex and neutering status were accounted for. Furthermore, an influence of antiseizure drug treatment upon the urinary neurotransmitter profile of serotonin and ɤ-aminobutyric acid concentration was revealed. This study demonstrated that the imbalances in the neurotransmitter system that causes epileptic seizures also leads to altered neurotransmitter elimination in the urine of affected dogs. Urinary neurotransmitters have the potential to serve as valuable biomarkers for diagnostics and treatment monitoring in canine epilepsy. However, more research on this topic needs to be undertaken to understand better the association between neurotransmitter deviations in the brain and urine neurotransmitter concentrations in dogs with idiopathic epilepsy.
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Affiliation(s)
- Teresa Schmidt
- Department of Small Animal Medicine and Surgery, University of Veterinary Medicine, Hannover, Germany
| | - Sebastian Meller
- Department of Small Animal Medicine and Surgery, University of Veterinary Medicine, Hannover, Germany
| | - Steven R. Talbot
- Institute for Laboratory Animal Science, Hannover Medical School, Hannover, Germany
| | - Benjamin A. Berk
- BrainCheck.Pet – Tierärztliche Praxis für Epilepsie, Sachsenstraße, Mannheim, Germany
- Department of Clinical Science and Services, Royal Veterinary College, Hatfield, United Kingdom
| | - Tsz H. Law
- Department of Clinical Science and Services, Royal Veterinary College, Hatfield, United Kingdom
| | - Sarah L. Hobbs
- Department of Clinical Science and Services, Royal Veterinary College, Hatfield, United Kingdom
| | - Nina Meyerhoff
- Department of Small Animal Medicine and Surgery, University of Veterinary Medicine, Hannover, Germany
| | - Rowena M. A. Packer
- Department of Clinical Science and Services, Royal Veterinary College, Hatfield, United Kingdom
| | - Holger A. Volk
- Department of Small Animal Medicine and Surgery, University of Veterinary Medicine, Hannover, Germany
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Ott M, Werneke U. Wernicke's encephalopathy - from basic science to clinical practice. Part 1: Understanding the role of thiamine. Ther Adv Psychopharmacol 2020; 10:2045125320978106. [PMID: 33447357 PMCID: PMC7780320 DOI: 10.1177/2045125320978106] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/10/2020] [Accepted: 11/10/2020] [Indexed: 01/19/2023] Open
Abstract
Wernicke's encephalopathy (WE) is an acute neuropsychiatric state. Untreated, WE can lead to coma or death, or progress to Korsakoff syndrome (KS) - a dementia characterized by irreversible loss of anterograde memory. Thiamine (vitamin B1) deficiency lies at the heart of this condition. Yet, our understanding of thiamine regarding prophylaxis and treatment of WE remains limited. This may contribute to the current undertreatment of WE in clinical practice. The overall aim of this review is to identify the best strategies for prophylaxis and treatment of WE in regard to (a) dose of thiamine, (b) mode of administration, (c) timing of switch from one mode of administration to another, (d) duration of administration, and (e) use of magnesium along thiamine as an essential cofactor. Evidence from randomized controlled trials and other intervention studies is virtually absent. Therefore, we have to resort to basic science for proof of principle instead. Here, we present the first part of our clinical review, in which we explore the physiology of thiamine and the pathophysiology of thiamine deficiency. We first explore both of these in their historical context. We then review the pharmacodynamics and pharmacokinetics of thiamine, exploring the roles of the six currently known thiamine compounds, their transporters, and target enzymes. We also explore the significance of magnesium as a cofactor in thiamine-facilitated enzymatic reactions and thiamine transport. In the second (forthcoming) part of this review, we will use the findings of the current review to make evidence-based inferences about strategies for prophylaxis and treatment of WE.
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Affiliation(s)
- Michael Ott
- Department of Public Health and Clinical Medicine, Division of Medicine, Umeå University, Umeå, Sweden
| | - Ursula Werneke
- Department of Clinical Sciences, Division of Psychiatry, Sunderby Research Unit, Umeå University, Umeå, Sweden
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3
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Modulating the Properties of Fe(III) Macrocyclic MRI Contrast Agents by Appending Sulfonate or Hydroxyl Groups. Molecules 2020; 25:molecules25102291. [PMID: 32414058 PMCID: PMC7288058 DOI: 10.3390/molecules25102291] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2020] [Revised: 05/07/2020] [Accepted: 05/10/2020] [Indexed: 12/30/2022] Open
Abstract
Complexes of Fe(III) that contain a triazacyclononane (TACN) macrocycle, two pendant hydroxyl groups, and a third ancillary pendant show promise as MRI contrast agents. The ancillary group plays an important role in tuning the solution relaxivity of the Fe(III) complex and leads to large changes in MRI contrast enhancement in mice. Two new Fe(III) complexes, one with a third coordinating hydroxypropyl pendant, Fe(L2), and one with an anionic non-coordinating sulfonate group, Fe(L1)(OH2), are compared. Both complexes have a deprotonated hydroxyl group at neutral pH and electrode potentials representative of a stabilized trivalent iron center. The r1 relaxivity of the Fe(L1)(OH2) complex is double that of the saturated complex, Fe(L2), at 4.7 T, 37 °C in buffered solutions. However, variable-temperature 17O-NMR experiments show that the inner-sphere water of Fe(L1)(OH2) does not exchange rapidly with bulk water under these conditions. The pendant sulfonate group in Fe(L1)(OH2) confers high solubility to the complex in comparison to Fe(L2) or previously studied analogues with benzyl groups. Dynamic MRI studies of the two complexes showed major differences in their pharmacokinetics clearance rates compared to an analogue containing a benzyl ancillary group. Rapid blood clearance and poor binding to serum albumin identify Fe(L1)(OH2) for development as an extracellular fluid contrast agent.
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Snyder EM, Asik D, Abozeid SM, Burgio A, Bateman G, Turowski SG, Spernyak JA, Morrow JR. A Class of Fe
III
Macrocyclic Complexes with Alcohol Donor Groups as Effective
T
1
MRI Contrast Agents. Angew Chem Int Ed Engl 2019. [DOI: 10.1002/ange.201912273] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Affiliation(s)
- Eric M. Snyder
- Department of Chemistry University at Buffalo State University of New York Amherst New York 14260 USA
| | - Didar Asik
- Department of Chemistry University at Buffalo State University of New York Amherst New York 14260 USA
| | - Samira M. Abozeid
- Department of Chemistry University at Buffalo State University of New York Amherst New York 14260 USA
| | - Ariel Burgio
- Department of Chemistry University at Buffalo State University of New York Amherst New York 14260 USA
| | - Gage Bateman
- Department of Chemistry University at Buffalo State University of New York Amherst New York 14260 USA
| | - Steven G. Turowski
- Department of Cell Stress Biology Roswell Park Comprehensive Cancer Center Buffalo New York 14263 USA
| | - Joseph A. Spernyak
- Department of Cell Stress Biology Roswell Park Comprehensive Cancer Center Buffalo New York 14263 USA
| | - Janet R. Morrow
- Department of Chemistry University at Buffalo State University of New York Amherst New York 14260 USA
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5
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Snyder EM, Asik D, Abozeid SM, Burgio A, Bateman G, Turowski SG, Spernyak JA, Morrow JR. A Class of Fe III Macrocyclic Complexes with Alcohol Donor Groups as Effective T 1 MRI Contrast Agents. Angew Chem Int Ed Engl 2019; 59:2414-2419. [PMID: 31725934 DOI: 10.1002/anie.201912273] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2019] [Revised: 11/07/2019] [Indexed: 12/12/2022]
Abstract
Early studies suggested that FeIII complexes cannot compete with GdIII complexes as T1 MRI contrast agents. Now it is shown that one member of a class of high-spin macrocyclic FeIII complexes produces more intense contrast in mice kidneys and liver at 30 minutes post-injection than does a commercially used GdIII agent and also produces similar T1 relaxivity in serum phantoms at 4.7 T and 37 °C. Comparison of four different FeIII macrocyclic complexes elucidates the factors that contribute to relaxivity in vivo including solution speciation. Variable-temperature 17 O NMR studies suggest that none of the complexes has a single, integral inner-sphere water that exchanges rapidly on the NMR timescale. MRI studies in mice show large in vivo differences of three of the FeIII complexes that correspond, in part, to their r1 relaxivity in phantoms. Changes in overall charge of the complex modulate contrast enhancement, especially of the kidneys.
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Affiliation(s)
- Eric M Snyder
- Department of Chemistry, University at Buffalo, State University of New York, Amherst, New York, 14260, USA
| | - Didar Asik
- Department of Chemistry, University at Buffalo, State University of New York, Amherst, New York, 14260, USA
| | - Samira M Abozeid
- Department of Chemistry, University at Buffalo, State University of New York, Amherst, New York, 14260, USA
| | - Ariel Burgio
- Department of Chemistry, University at Buffalo, State University of New York, Amherst, New York, 14260, USA
| | - Gage Bateman
- Department of Chemistry, University at Buffalo, State University of New York, Amherst, New York, 14260, USA
| | - Steven G Turowski
- Department of Cell Stress Biology, Roswell Park Comprehensive Cancer Center, Buffalo, New York, 14263, USA
| | - Joseph A Spernyak
- Department of Cell Stress Biology, Roswell Park Comprehensive Cancer Center, Buffalo, New York, 14263, USA
| | - Janet R Morrow
- Department of Chemistry, University at Buffalo, State University of New York, Amherst, New York, 14260, USA
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Wagner DJ, Hu T, Wang J. Polyspecific organic cation transporters and their impact on drug intracellular levels and pharmacodynamics. Pharmacol Res 2016; 111:237-246. [PMID: 27317943 DOI: 10.1016/j.phrs.2016.06.002] [Citation(s) in RCA: 52] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/19/2016] [Accepted: 06/02/2016] [Indexed: 01/11/2023]
Abstract
Most drugs are intended to act on molecular targets residing within a specific tissue or cell type. Therefore, the drug concentration within the target tissue or cells is most relevant to its pharmacological effect. Increasing evidences suggest that drug transporters not only play a significant role in governing systemic drug levels, but are also an important gate keeper for intra-tissue and intracellular drug concentrations. This review focuses on polyspecific organic cation transporters, which include the organic cation transporters 1-3 (OCT1-3), the multidrug and toxin extrusion proteins 1-2 (MATE1-2) and the plasma membrane monoamine transporter (PMAT). Following an overview of the tissue distribution, transport mechanisms, and functional characteristics of these transporters, we highlight the studies demonstrating the ability of locally expressed OCTs to impact intracellular drug concentrations and directly influence their pharmacological and toxicological activities. Specifically, OCT1-mediated metformin access to its site of action in the liver is impacted by genetic polymorphisms and chemical inhibition of OCT1. The impact of renal OCT2 and MATE1/2-K in cisplatin intrarenal accumulation and nephrotoxicity is reviewed. New data demonstrating the role of OCT3 in salivary drug accumulation and secretion is discussed. Whenever possible, the pharmacodynamic response and toxicological effects is presented and discussed in light of intra-tissue and intracellular drug exposure. Current challenges, knowledge gaps, and future research directions are discussed. Understanding the impact of transporters on intra-tissue and intracellular drug concentrations has important implications for rational-based optimization of drug efficacy and safety.
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Affiliation(s)
- David J Wagner
- Department of Pharmaceutics, University of Washington, Seattle, WA, United States.
| | - Tao Hu
- Department of Pharmaceutics, University of Washington, Seattle, WA, United States.
| | - Joanne Wang
- Department of Pharmaceutics, University of Washington, Seattle, WA, United States.
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Cabedo Martinez AI, Weinhäupl K, Lee WK, Wolff NA, Storch B, Żerko S, Konrat R, Koźmiński W, Breuker K, Thévenod F, Coudevylle N. Biochemical and Structural Characterization of the Interaction between the Siderocalin NGAL/LCN2 (Neutrophil Gelatinase-associated Lipocalin/Lipocalin 2) and the N-terminal Domain of Its Endocytic Receptor SLC22A17. J Biol Chem 2015; 291:2917-30. [PMID: 26635366 PMCID: PMC4742754 DOI: 10.1074/jbc.m115.685644] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2015] [Indexed: 11/22/2022] Open
Abstract
The neutrophil gelatinase-associated lipocalin (NGAL, also known as LCN2) and its cellular receptor (LCN2-R, SLC22A17) are involved in many physiological and pathological processes such as cell differentiation, apoptosis, and inflammation. These pleiotropic functions mainly rely on NGAL's siderophore-mediated iron transport properties. However, the molecular determinants underlying the interaction between NGAL and its cellular receptor remain largely unknown. Here, using solution-state biomolecular NMR in conjunction with other biophysical methods, we show that the N-terminal domain of LCN2-R is a soluble extracellular domain that is intrinsically disordered and interacts with NGAL preferentially in its apo state to form a fuzzy complex. The relatively weak affinity (≈10 μm) between human LCN2-R-NTD and apoNGAL suggests that the N terminus on its own cannot account for the internalization of NGAL by LCN2-R. However, human LCN2-R-NTD could be involved in the fine-tuning of the interaction between NGAL and its cellular receptor or in a biochemical mechanism allowing the receptor to discriminate between apo- and holo-NGAL.
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Affiliation(s)
- Ana-Isabel Cabedo Martinez
- From the Department of Computational and Structural Biology, Max F. Perutz Laboratories, University of Vienna, Campus Vienna Biocenter 5, 1030 Vienna, Austria
| | - Katharina Weinhäupl
- From the Department of Computational and Structural Biology, Max F. Perutz Laboratories, University of Vienna, Campus Vienna Biocenter 5, 1030 Vienna, Austria
| | - Wing-Kee Lee
- Chair of Physiology, Pathophysiology, and Toxicology and ZBAF, Faculty of Health, School of Medicine, Witten/Herdecke University, Stockumer Strasse 12, 58453 Witten, Germany
| | - Natascha A Wolff
- Chair of Physiology, Pathophysiology, and Toxicology and ZBAF, Faculty of Health, School of Medicine, Witten/Herdecke University, Stockumer Strasse 12, 58453 Witten, Germany
| | - Barbara Storch
- Institute of Organic Chemistry and Center for Molecular Biosciences Innsbruck, University of Innsbruck, CCB, Innrain 80/82, 6020 Innsbruck, Austria, and
| | - Szymon Żerko
- Faculty of Chemistry, Biological and Chemical Research Centre, University of Warsaw, Żwirki i Wigury 101, 02-089 Warsaw, Poland
| | - Robert Konrat
- From the Department of Computational and Structural Biology, Max F. Perutz Laboratories, University of Vienna, Campus Vienna Biocenter 5, 1030 Vienna, Austria
| | - Wiktor Koźmiński
- Faculty of Chemistry, Biological and Chemical Research Centre, University of Warsaw, Żwirki i Wigury 101, 02-089 Warsaw, Poland
| | - Kathrin Breuker
- Institute of Organic Chemistry and Center for Molecular Biosciences Innsbruck, University of Innsbruck, CCB, Innrain 80/82, 6020 Innsbruck, Austria, and
| | - Frank Thévenod
- Chair of Physiology, Pathophysiology, and Toxicology and ZBAF, Faculty of Health, School of Medicine, Witten/Herdecke University, Stockumer Strasse 12, 58453 Witten, Germany
| | - Nicolas Coudevylle
- From the Department of Computational and Structural Biology, Max F. Perutz Laboratories, University of Vienna, Campus Vienna Biocenter 5, 1030 Vienna, Austria,
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McLatchie LM, Young JS, Fry CH. Regulation of ACh release from guinea pig bladder urothelial cells: potential role in bladder filling sensations. Br J Pharmacol 2014; 171:3394-403. [PMID: 24628015 PMCID: PMC4105928 DOI: 10.1111/bph.12682] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2013] [Revised: 02/25/2014] [Accepted: 03/01/2014] [Indexed: 11/30/2022] Open
Abstract
BACKGROUND AND PURPOSE The aim of this study was to quantify and characterize the mechanism of non-neuronal ACh release from bladder urothelial cells and to determine if urothelial cells could be a site of action of anti-muscarinic drugs. EXPERIMENTAL APPROACH A novel technique was developed whereby ACh could be measured from freshly isolated guinea pig urothelial cells in suspension following mechanical stimulation. Various agents were used to manipulate possible ACh release pathways in turn and to study the effects of muscarinic receptor activation and inhibition on urothelial ATP release. KEY RESULTS Minimal mechanical stimulus achieved full ACh release, indicating a small dynamic range and possible all-or-none signal. ACh release involved a mechanism dependent on the anion channel CFTR and intracellular calcium concentration, but was independent of extracellular calcium, vesicular trafficking, connexins or pannexins, organic cation transporters and was not affected by botulinum-A toxin. Stimulating ACh receptors increased ATP production and antagonizing them reduced ATP release, suggesting a link between ACh and ATP release. CONCLUSIONS AND IMPLICATIONS These results suggest that release of non-neuronal ACh from the urothelium is large enough and well located to act as a modulator of ATP release. It is hypothesized that this pathway may contribute to the actions of anti-muscarinic drugs in reducing the symptoms of lower urinary tract syndromes. Additionally the involvement of CFTR in ACh release suggests an exciting new direction for the treatment of these conditions.
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Affiliation(s)
- L M McLatchie
- Department of Biochemistry and Physiology, FHMS, University of Surrey, Guildford, UK
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Properties and regulation of organic cation transport in freshly isolated mouse proximal tubules analyzed with a fluorescence reader-based method. Pflugers Arch 2011; 462:359-69. [PMID: 21523352 DOI: 10.1007/s00424-011-0969-7] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2011] [Revised: 04/06/2011] [Accepted: 04/11/2011] [Indexed: 01/08/2023]
Abstract
The main elimination site of organic cations (OCs) is the renal proximal tubule (PT). OC transporters (OCT) accept endogenous and exogenous substances and xenobiotics. As transgenic mouse models are increasingly used in translational medicine, functional properties with special focus on regulation of OCT of isolated mouse PTs were studied with a new fluorescence reader-based method, which allows studying larger numbers of tubules per kidney. OC transport across the basolateral membrane of PTs from male mice was measured as initial uptake of the fluorescent dye 4-(4-(dimethylamino)styryl)-N-methylpyridinium (ASP). A microtiter plate fluorescence reader was used to semi-automatically analyze OC transport in freshly isolated tubules. Relative mRNA expression of OCT1/OCT2/OCT3 in PTs was 1/0.3/0.01 and did not vary from S1 to S3 segments. ASP was transported by PTs with a K (m) of 6 μM. It was inhibited by TEA, TPA, or cimetidine (IC(50)=5, 19, or 53 μM, respectively). Angiotensin II stimulated ASP uptake (+63%), while stimulation of PKC reduced (-37%) OC transport. Inhibition of p56(lck) tyrosine kinase (-60%), of PI3K (-36%), of Ca(2+)/calmodulin (-25%), or of PKA (-33%) reduced OC transport. In PTs from OCT1/2(-/-) mice ASP uptake was reduced to ~20%. Using this fluorescence reader-based method, we report substrate specificities and a complex pattern of acute regulation of OC transport in isolated mouse PTs. Compared to isolated human PTs or rat and human OCT isoforms expressed in HEK293-cells, OC transport across the basolateral membrane of freshly isolated mouse PTs shows similarities but also specific differences.
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Expression and analysis of two novel rat organic cation transporter homologs, SLC22A17 and SLC22A23. Mol Cell Biochem 2011; 352:143-54. [PMID: 21359964 DOI: 10.1007/s11010-011-0748-y] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2010] [Accepted: 02/17/2011] [Indexed: 01/11/2023]
Abstract
The organic cation transporter (OCT, SLC22) family is a family of polyspecific transmembrane proteins that are responsible for the uptake or excretion of many cationic drugs, toxins, and endogenous metabolites in a variety of tissues. Many of the OCTs have been previously characterized, but there are a number of orphan genes whose functions remain unknown. In this study, two novel rat SLC22 genes, SLC22A17 (BOCT1) and SLC22A23 (BOCT2), were cloned and characterized. Northern blot analysis showed that BOCT1 and BOCT2 mRNA was expressed in a wide variety of tissues. BOCT1 was strongly expressed in brain, primary neurons and brain endothelial cells, with highest expression in choroid plexus. BOCT2 was also abundantly expressed in brain, as well as in liver. To characterize the products of these genes, BOCT1 cDNA was isolated from a rat blood-brain barrier cDNA library, and BOCT2 cDNA was isolated from rat brain capillary and from cultured neurons using PCR techniques. Plasmids expressing BOCT1 and BOCT2 were transfected into HEK-293 cells, as were control cDNAs for OCT1 and OCTN2. Recombinant cell surface protein was verified by western blot and fluorescence microscopy. Transport activity of BOCT1 and BOCT2 was evaluated using radioisotope uptake assays. The OCT1- and OCTN2-expressing cells transported the canonical substrates, 1-methyl-4-phenyl-pyridinium (MPP(+)) and carnitine, respectively. However, BOCT1 and BOCT2-expressing cells did not show transport activity for these substrates or a number of other SLC22 substrates. These novel family members have a nonconserved amino terminus, relative to other OCTs, that may preclude typical SLC22 transport function.
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Gaur M, Puri N, Manoharlal R, Rai V, Mukhopadhayay G, Choudhury D, Prasad R. MFS transportome of the human pathogenic yeast Candida albicans. BMC Genomics 2008; 9:579. [PMID: 19055746 PMCID: PMC2636803 DOI: 10.1186/1471-2164-9-579] [Citation(s) in RCA: 76] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2008] [Accepted: 12/03/2008] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The major facilitator superfamily (MFS) is one of the two largest superfamilies of membrane transporters present ubiquitously in bacteria, archaea, and eukarya and includes members that function as uniporters, symporters or antiporters. We report here the complete transportome of MFS proteins of a human pathogenic yeast Candida albicans. RESULTS Computational analysis of C. albicans genome enabled us to identify 95 potential MFS proteins which clustered into 17 families using Saier's Transport Commission (TC) system. Among these SP, DHA1, DHA2 and ACS represented major families consisting of 22, 22, 9 and 16 members, respectively. Family designations in C. albicans were validated by subjecting Saccharomyces cerevisiae genome to TC system. Based on the published available genomics/proteomics data, 87 of the putative MFS genes of C. albicans were found to express either at mRNA or protein levels. We checked the expression of the remaining 8 genes by using RT-PCR and observed that they are not expressed under basal growth conditions implying that either these 8 genes are expressed under specific growth conditions or they may be candidates for pseudogenes. CONCLUSION The in silico characterisation of MFS transporters in Candida albicans genome revealed a large complement of MFS transporters with most of them showing expression. Considering the clinical relevance of C. albicans and role of MFS members in antifungal resistance and nutrient transport, this analysis would pave way for identifying their physiological relevance.
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Affiliation(s)
- Manisha Gaur
- Special Centre for Molecular Medicine, Jawaharlal Nehru University, New Delhi, India.
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Ciarimboli G, Schlatter E. Regulation of organic cation transport. Pflugers Arch 2004; 449:423-41. [PMID: 15688244 DOI: 10.1007/s00424-004-1355-5] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2004] [Accepted: 09/27/2004] [Indexed: 01/11/2023]
Abstract
Transport of organic cations (OC) is important for the recycling of endogenous OC and also a necessary step for detoxification of exogenous OC in the body. Even though the identification and characterisation of numerous OC transporters in recent years has allowed the elucidation of molecular mechanisms underlying OC transport, elucidation of the regulation of this transport is just beginning. This review summarises the general properties of OC transport and then analyses the literature on the regulation of these processes. Studies on short- and long-term regulation of OC transport are considered separately. Important aspects of short-term regulation have been clarified and the regulatory pathways of several OC transporters have been characterised. Short-term regulation appears to be transporter subtype-, tissue- and species-dependent and to involve transporter phosphorylation. Transporter phosphorylation may alter the affinity for substrates or/and expression on the plasma membrane. Even though several studies have shown long-term regulation of OC transport, the pathophysiological meaning of these changes are not well understood. In this case, regulation seems to be subtype-, tissue- and gender-specific. Further research is necessary to clarify this important issue of regulation of OC transport.
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Affiliation(s)
- Giuliano Ciarimboli
- Experimentelle Nephrologie, Medizinische Klinik und Poliklinik D, Universitätsklinikum Münster, Domagkstrasse 3a, 48149, Münster, Germany.
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