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Gründemann D, Hartmann L, Flögel S. The Ergothioneine Transporter (ETT): Substrates and Locations, an Inventory. FEBS Lett 2021; 596:1252-1269. [PMID: 34958679 DOI: 10.1002/1873-3468.14269] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2021] [Revised: 12/21/2021] [Accepted: 12/22/2021] [Indexed: 11/07/2022]
Abstract
In all vertebrates including mammals, the ergothioneine transporter ETT (obsolete name OCTN1; human gene symbol SLC22A4) is a powerful and highly specific transporter for the uptake of ergothioneine (ET). ETT is not expressed ubiquitously and only cells with high ETT cell-surface levels can accumulate ET to high concentration. Without ETT, there is no uptake because the plasma membrane is essentially impermeable to this hydrophilic zwitterion. Here, we review the substrate specificity and localization of ETT, which is prominently expressed in neutrophils, monocytes/macrophages, and developing erythrocytes. Most sites of strong expression are conserved across species, but there are also major differences. In particular, we critically analyze the evidence for the expression of ETT in the brain as well as recent data suggesting that the transporter SLC22A15 may transport also ET. We conclude that, to date, ETT remains the only well-defined biomarker for intracellular ET activity. In humans, the ability to take up, distribute, and retain ET depends principally on this transporter.
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Affiliation(s)
- Dirk Gründemann
- Department of Pharmacology, University of Cologne, Faculty of Medicine and University Hospital Cologne, Gleueler Straße 24, 50931, Cologne, Germany
| | - Lea Hartmann
- Department of Pharmacology, University of Cologne, Faculty of Medicine and University Hospital Cologne, Gleueler Straße 24, 50931, Cologne, Germany
| | - Svenja Flögel
- Department of Pharmacology, University of Cologne, Faculty of Medicine and University Hospital Cologne, Gleueler Straße 24, 50931, Cologne, Germany
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Yee SW, Giacomini KM. Emerging Roles of the Human Solute Carrier 22 Family. Drug Metab Dispos 2021; 50:DMD-MR-2021-000702. [PMID: 34921098 PMCID: PMC9488978 DOI: 10.1124/dmd.121.000702] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2021] [Revised: 11/22/2021] [Accepted: 12/08/2021] [Indexed: 11/22/2022] Open
Abstract
The human Solute Carrier 22 family (SLC22), also termed the organic ion transporter family, consists of 28 distinct multi-membrane spanning proteins, which phylogenetically cluster together according to their charge specificity for organic cations (OCTs), organic anions (OATs) and organic zwitterion/cations (OCTNs). Some SLC22 family members are well characterized in terms of their substrates, transport mechanisms and expression patterns, as well as their roles in human physiology and pharmacology, whereas others remain orphans with no known ligands. Pharmacologically, SLC22 family members play major roles as determinants of the absorption and disposition of many prescription drugs, and several including the renal transporters, OCT2, OAT1 and OAT3 are targets for many clinically important drug-drug interactions. In addition, mutations in some of these transporters (SLC22A5 (OCTN2) and SLC22A12 (URAT1) lead to rare monogenic disorders. Genetic polymorphisms in SLC22 transporters have been associated with common human disease, drug response and various phenotypic traits. Three members in this family were deorphaned in very recently: SLC22A14, SLC22A15 and SLC22A24, and found to transport specific compounds such as riboflavin (SLC22A14), anti-oxidant zwitterions (SLC22A15) and steroid conjugates (SLC22A24). Their physiologic and pharmacological roles need further investigation. This review aims to summarize the substrates, expression patterns and transporter mechanisms of individual SLC22 family members and their roles in human disease and drug disposition and response. Gaps in our understanding of SLC22 family members are described. Significance Statement In recent years, three members of the SLC22 family of transporters have been deorphaned and found to play important roles in the transport of diverse solutes. New research has furthered our understanding of the mechanisms, pharmacological roles, and clinical impact of SLC22 transporters. This minireview provides overview of SLC22 family members of their physiologic and pharmacologic roles, the impact of genetic variants in the SLC22 family on disease and drug response, and summary of recent studies deorphaning SLC22 family members.
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Affiliation(s)
- Sook Wah Yee
- Bioengineering and Therapeutic Sciences, Univerity of California, San Francisco, United States
| | - Kathleen M Giacomini
- Bioengineering and Therapeutic Sciences, Univerity of California, San Francisco, United States
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Borodina I, Kenny LC, McCarthy CM, Paramasivan K, Pretorius E, Roberts TJ, van der Hoek SA, Kell DB. The biology of ergothioneine, an antioxidant nutraceutical. Nutr Res Rev 2020; 33:190-217. [PMID: 32051057 PMCID: PMC7653990 DOI: 10.1017/s0954422419000301] [Citation(s) in RCA: 100] [Impact Index Per Article: 25.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2019] [Revised: 11/20/2019] [Accepted: 11/25/2019] [Indexed: 02/07/2023]
Abstract
Ergothioneine (ERG) is an unusual thio-histidine betaine amino acid that has potent antioxidant activities. It is synthesised by a variety of microbes, especially fungi (including in mushroom fruiting bodies) and actinobacteria, but is not synthesised by plants and animals who acquire it via the soil and their diet, respectively. Animals have evolved a highly selective transporter for it, known as solute carrier family 22, member 4 (SLC22A4) in humans, signifying its importance, and ERG may even have the status of a vitamin. ERG accumulates differentially in various tissues, according to their expression of SLC22A4, favouring those such as erythrocytes that may be subject to oxidative stress. Mushroom or ERG consumption seems to provide significant prevention against oxidative stress in a large variety of systems. ERG seems to have strong cytoprotective status, and its concentration is lowered in a number of chronic inflammatory diseases. It has been passed as safe by regulatory agencies, and may have value as a nutraceutical and antioxidant more generally.
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Affiliation(s)
- Irina Borodina
- The Novo Nordisk Foundation Center for Biosustainability, Building 220, Chemitorvet 200, Technical University of Denmark, 2800Kongens Lyngby, Denmark
| | - Louise C. Kenny
- Department of Women’s and Children’s Health, Institute of Translational Medicine, University of Liverpool, Crown Street, LiverpoolL8 7SS, UK
| | - Cathal M. McCarthy
- Irish Centre for Fetal and Neonatal Translational Research (INFANT), Cork University Maternity Hospital, Cork, Republic of Ireland
- Department of Pharmacology and Therapeutics, Western Gateway Building, University College Cork, Cork, Republic of Ireland
| | - Kalaivani Paramasivan
- The Novo Nordisk Foundation Center for Biosustainability, Building 220, Chemitorvet 200, Technical University of Denmark, 2800Kongens Lyngby, Denmark
| | - Etheresia Pretorius
- Department of Physiological Sciences, Faculty of Science, Stellenbosch University, Stellenbosch, Private Bag X1 Matieland, 7602, South Africa
| | - Timothy J. Roberts
- Department of Physiological Sciences, Faculty of Science, Stellenbosch University, Stellenbosch, Private Bag X1 Matieland, 7602, South Africa
- Department of Biochemistry, Institute of Integrative Biology, Faculty of Health and Life Sciences, University of Liverpool, Crown Street, LiverpoolL69 7ZB, UK
| | - Steven A. van der Hoek
- The Novo Nordisk Foundation Center for Biosustainability, Building 220, Chemitorvet 200, Technical University of Denmark, 2800Kongens Lyngby, Denmark
| | - Douglas B. Kell
- The Novo Nordisk Foundation Center for Biosustainability, Building 220, Chemitorvet 200, Technical University of Denmark, 2800Kongens Lyngby, Denmark
- Department of Physiological Sciences, Faculty of Science, Stellenbosch University, Stellenbosch, Private Bag X1 Matieland, 7602, South Africa
- Department of Biochemistry, Institute of Integrative Biology, Faculty of Health and Life Sciences, University of Liverpool, Crown Street, LiverpoolL69 7ZB, UK
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Pochini L, Pappacoda G, Galluccio M, Pastore F, Scalise M, Indiveri C. Effect of Cholesterol on the Organic Cation Transporter OCTN1 (SLC22A4). Int J Mol Sci 2020; 21:ijms21031091. [PMID: 32041338 PMCID: PMC7037232 DOI: 10.3390/ijms21031091] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2019] [Revised: 02/02/2020] [Accepted: 02/03/2020] [Indexed: 02/07/2023] Open
Abstract
The effect of cholesterol was investigated on the OCTN1 transport activity measured as [14C]-tetraethylamonium or [3H]-acetylcholine uptake in proteoliposomes reconstituted with native transporter extracted from HeLa cells or the human recombinant OCTN1 over-expressed in E. coli. Removal of cholesterol from the native transporter by MβCD before reconstitution led to impairment of transport activity. A similar activity impairment was observed after treatment of proteoliposomes harboring the recombinant (cholesterol-free) protein by MβCD, suggesting that the lipid mixture used for reconstitution contained some cholesterol. An enzymatic assay revealed the presence of 10 µg cholesterol/mg total lipids corresponding to 1% cholesterol in the phospholipid mixture used for the proteoliposome preparation. On the other way around, the activity of the recombinant OCTN1 was stimulated by adding the cholesterol analogue, CHS to the proteoliposome preparation. Optimal transport activity was detected in the presence of 83 µg CHS/ mg total lipids for both [14C]-tetraethylamonium or [3H]-acetylcholine uptake. Kinetic analysis of transport demonstrated that the stimulation of transport activity by CHS consisted in an increase of the Vmax of transport with no changes of the Km. Altogether, the data suggests a direct interaction of cholesterol with the protein. A further support to this interpretation was given by a docking analysis indicating the interaction of cholesterol with some protein sites corresponding to CARC-CRAC motifs. The observed direct interaction of cholesterol with OCTN1 points to a possible direct influence of cholesterol on tumor cells or on acetylcholine transport in neuronal and non-neuronal cells via OCTN1.
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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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