1
|
Sha L, Yong X, Shao Z, Duan Y, Hong Q, Zhang J, Zhang Y, Chen L. Targeting adverse effects of antiseizure medication on offspring: current evidence and new strategies for safety. Expert Rev Neurother 2023; 23:141-156. [PMID: 36731825 DOI: 10.1080/14737175.2023.2176751] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
INTRODUCTION For women with epilepsy of reproductive age, antiseizure medications (ASMs) are associated with an increased risk of offspring malformations. There are safety concerns for most anti-seizure medications in the perinatal period, and there is a clear need to identify safe medications. ASMs must transport through biological barriers to exert toxic effects on the fetus, and transporters play essential roles in trans-barrier drug transport. Therefore, it is vital to understand the distribution and properties of ASM-related transporters in biological barriers. AREAS COVERED This study reviews the structure, transporter distribution, and properties of the blood-brain, placental, and blood-milk barrier, and summarizes the existing evidence for the trans-barrier transport mechanism of ASMs and standard experimental models of biological barriers. EXPERT OPINION Ideal ASMs in the perinatal period should have the following characteristics: 1) Increased transport through the blood-brain barrier, and 2) Reduced transport of the placental and blood-milk barriers. Thus, only low-dose or almost no antiseizure medication could enter the fetus's body, which could decrease medication-induced fetal abnormalities. Based on the stimulated structure and molecular docking, we propose a development strategy for new ASMs targeting transporters of biological barriers to improve the perinatal treatment of female patients with epilepsy.
Collapse
Affiliation(s)
- Leihao Sha
- Department of Neurology, Joint Research Institution of Altitude Health, West China Hospital, Sichuan University, Chengdu, 610041, Sichuan
| | - Xihao Yong
- Division of Nephrology and Kidney Research Institute, State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University, Chengdu, 610041, China
| | - Zhenhua Shao
- Division of Nephrology and Kidney Research Institute, State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University, Chengdu, 610041, China
| | - Yifei Duan
- Department of Neurology, Joint Research Institution of Altitude Health, West China Hospital, Sichuan University, Chengdu, 610041, Sichuan
| | - Qiulei Hong
- Department of Neurology, Joint Research Institution of Altitude Health, West China Hospital, Sichuan University, Chengdu, 610041, Sichuan
| | - Jifa Zhang
- Department of Neurology, Joint Research Institution of Altitude Health, West China Hospital, Sichuan University, Chengdu, 610041, Sichuan
| | - Yunwu Zhang
- The current form, Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, School of Medicine, Xiamen University, Xiamen, 361102, China
| | - Lei Chen
- Department of Neurology, Joint Research Institution of Altitude Health, West China Hospital, Sichuan University, Chengdu, 610041, Sichuan
| |
Collapse
|
2
|
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.
Collapse
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
| |
Collapse
|
3
|
Cheah IK, Halliwell B. Ergothioneine, recent developments. Redox Biol 2021; 42:101868. [PMID: 33558182 PMCID: PMC8113028 DOI: 10.1016/j.redox.2021.101868] [Citation(s) in RCA: 68] [Impact Index Per Article: 22.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2020] [Revised: 01/14/2021] [Accepted: 01/14/2021] [Indexed: 02/06/2023] Open
Abstract
There has been a recent surge of interest in the unique low molecular weight dietary thiol/thione, ergothioneine. This compound can accumulate at high levels in the body from diet and may play important physiological roles in human health and development, and possibly in prevention and treatment of disease. Blood levels of ergothioneine decline with age and onset of various diseases. Here we highlight recent advances in our knowledge of ergothioneine.
Collapse
Affiliation(s)
- Irwin K Cheah
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, 117596, Singapore; Life Science Institute, Neurobiology Programme, Centre for Life Sciences, National University of Singapore, 117456, Singapore
| | - Barry Halliwell
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, 117596, Singapore; Life Science Institute, Neurobiology Programme, Centre for Life Sciences, National University of Singapore, 117456, Singapore.
| |
Collapse
|
4
|
Transporters in the Mammary Gland-Contribution to Presence of Nutrients and Drugs into Milk. Nutrients 2019; 11:nu11102372. [PMID: 31590349 PMCID: PMC6836069 DOI: 10.3390/nu11102372] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2019] [Revised: 09/19/2019] [Accepted: 09/25/2019] [Indexed: 02/07/2023] Open
Abstract
A large number of nutrients and bioactive ingredients found in milk play an important role in the nourishment of breast-fed infants and dairy consumers. Some of these ingredients include physiologically relevant compounds such as vitamins, peptides, neuroactive compounds and hormones. Conversely, milk may contain substances-drugs, pesticides, carcinogens, environmental pollutants-which have undesirable effects on health. The transfer of these compounds into milk is unavoidably linked to the function of transport proteins. Expression of transporters belonging to the ATP-binding cassette (ABC-) and Solute Carrier (SLC-) superfamilies varies with the lactation stages of the mammary gland. In particular, Organic Anion Transporting Polypeptides 1A2 (OATP1A2) and 2B1 (OATP2B1), Organic Cation Transporter 1 (OCT1), Novel Organic Cation Transporter 1 (OCTN1), Concentrative Nucleoside Transporters 1, 2 and 3 (CNT1, CNT2 and CNT3), Peptide Transporter 2 (PEPT2), Sodium-dependent Vitamin C Transporter 2 (SVCT2), Multidrug Resistance-associated Protein 5 (ABCC5) and Breast Cancer Resistance Protein (ABCG2) are highly induced during lactation. This review will focus on these transporters overexpressed during lactation and their role in the transfer of products into the milk, including both beneficial and harmful compounds. Furthermore, additional factors, such as regulation, polymorphisms or drug-drug interactions will be described.
Collapse
|
5
|
Ito S. Emerging Research Paradigm for Infant Drug Exposure Through Breast Milk. Curr Pharm Des 2019; 25:528-533. [DOI: 10.2174/1381612825666190318165932] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2019] [Accepted: 03/16/2019] [Indexed: 01/16/2023]
Abstract
Background:
Information on drug secretion into milk is insufficient due to the exclusion of lactating
women from clinical trials and drug development processes. As a result, non-adherence to the necessary drug
therapy and discontinuation of breastfeeding occur, even if the predicted level of infant exposure is low. In contrast,
inadvertent infant exposure to drugs in breast milk continues to happen due to lack of rational risk assessment,
resulting in serious toxicity cases including death. This problem is multifactorial, but one of the key elements
is the lack of pharmacokinetic information on drug secretion into milk and resultant infant exposure levels,
the first line of evidence for risk assessment.
Methods:
Basic PK principles in drug excretion into milk were explained. The literature was scanned to identify
approaches for PK data acquisition in this challenging field.
Results:
This review describes the feasibility to develop such approaches, and the knowledge gaps that still exist.
A combination of population pharmacokinetics approach (to estimate averages and variations of drug concentration
profiles in milk) and physiologically-based pharmacokinetics modeling of infants (to predict the population
profiles of infant drug exposure levels) appears useful.
Conclusions:
In order to facilitate participant enrollment and PK data acquisition in a timely manner, networks of
investigators become crucial.
Collapse
Affiliation(s)
- Shinya Ito
- Division of Clinical Pharmacology and Toxicology, Hospital for Sick Children, 555 University Avenue, Toronto, Ontario M5G 1X8, Canada
| |
Collapse
|
6
|
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.
Collapse
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
| |
Collapse
|
7
|
Abstract
One impediment to breastfeeding is the lack of information on the use of many drugs during lactation, especially newer ones. The principles of drug passage into breastmilk are well established, but have often not been optimally applied prospectively. Commonly used preclinical rodent models for determining drug excretion into milk are very unreliable because of marked differences in milk composition and transporters compared to those of humans. Measurement of drug concentrations in humans remains the gold standard, but computer modeling is promising. New FDA labeling requirements present an opportunity to apply modeling to preclinical drug development in place of conventional animal testing for drug excretion into breastmilk, which should improve the use of medications in nursing mothers.
Collapse
|
8
|
Mihaljevic I, Popovic M, Zaja R, Smital T. Phylogenetic, syntenic, and tissue expression analysis of slc22 genes in zebrafish (Danio rerio). BMC Genomics 2016; 17:626. [PMID: 27519738 PMCID: PMC4982206 DOI: 10.1186/s12864-016-2981-y] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2016] [Accepted: 07/29/2016] [Indexed: 01/11/2023] Open
Abstract
BACKGROUND SLC22 protein family is a member of the SLC (Solute carriers) superfamily of polyspecific membrane transporters responsible for uptake of a wide range of organic anions and cations, including numerous endo- and xenobiotics. Due to the lack of knowledge on zebrafish Slc22 family, we performed initial characterization of these transporters using a detailed phylogenetic and conserved synteny analysis followed by the tissue specific expression profiling of slc22 transcripts. RESULTS We identified 20 zebrafish slc22 genes which are organized in the same functional subgroups as human SLC22 members. Orthologies and syntenic relations between zebrafish and other vertebrates revealed consequences of the teleost-specific whole genome duplication as shown through one-to-many orthologies for certain zebrafish slc22 genes. Tissue expression profiles of slc22 transcripts were analyzed using qRT-PCR determinations in nine zebrafish tissues: liver, kidney, intestine, gills, brain, skeletal muscle, eye, heart, and gonads. Our analysis revealed high expression of oct1 in kidney, especially in females, followed by oat3 and oat2c in females, oat2e in males and orctl4 in females. oct1 was also dominant in male liver. oat2d showed the highest expression in intestine with less noticeable gender differences. All slc22 genes showed low expression in gills, and moderate expression in heart and skeletal muscle. Dominant genes in brain were oat1 in females and oct1 in males, while the highest gender differences were determined in gonads, with dominant expression of almost all slc22 genes in testes and the highest expression of oat2a. CONCLUSIONS Our study offers the first insight into the orthology relationships, gene expression and potential role of Slc22 membrane transporters in zebrafish. Clear orthological relationships of zebrafish slc22 and other vertebrate slc22 genes were established. slc22 members are mostly highly conserved, suggesting their physiological and toxicological importance. One-to-many orthologies and differences in tissue expression patterns of zebrafish slc22 genes in comparison to human orthologs were observed. Our expression data point to partial similarity of zebrafish versus human Slc22 members, with possible compensatory roles of certain zebrafish transporters, whereas higher number of some orthologs implies potentially more diverse and specific roles of these proteins in zebrafish.
Collapse
Affiliation(s)
- Ivan Mihaljevic
- Division for Marine and Environmental Research, Laboratory for Molecular Ecotoxicology, Ruđer Bošković Institute, Bijenička cesta 54, 10000, Zagreb, Croatia
| | - Marta Popovic
- Division for Marine and Environmental Research, Laboratory for Molecular Ecotoxicology, Ruđer Bošković Institute, Bijenička cesta 54, 10000, Zagreb, Croatia.,Department of Oncology, University of Oxford, Old Road Campus Research Building, Roosevelt Drive, Oxford, UK
| | - Roko Zaja
- Division for Marine and Environmental Research, Laboratory for Molecular Ecotoxicology, Ruđer Bošković Institute, Bijenička cesta 54, 10000, Zagreb, Croatia.,Sir William Dunn School of Pathology, University of Oxford, Oxford, England, UK
| | - Tvrtko Smital
- Division for Marine and Environmental Research, Laboratory for Molecular Ecotoxicology, Ruđer Bošković Institute, Bijenička cesta 54, 10000, Zagreb, Croatia.
| |
Collapse
|
9
|
Yagdiran Y, Oskarsson A, Knight CH, Tallkvist J. ABC- and SLC-Transporters in Murine and Bovine Mammary Epithelium--Effects of Prochloraz. PLoS One 2016; 11:e0151904. [PMID: 27028005 PMCID: PMC4814071 DOI: 10.1371/journal.pone.0151904] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2016] [Accepted: 02/15/2016] [Indexed: 01/16/2023] Open
Abstract
Some chemicals are ligands to efflux transporters which may result in high concentrations in milk. Limited knowledge is available on the influence of maternal exposure to chemicals on the expression and function of transporters in the lactating mammary gland. We determined gene expression of ABC and SLC transporters in murine mammary tissue of different gestation and lactation stages, in murine mammary cells (HC11) featuring resting and secreting phenotypes and in bovine mammary tissue and cells (BME-UV). Effects on transporter expression and function of the imidazole fungicide prochloraz, previously reported to influence BCRP in mammary cells, was investigated on transporter expression and function in the two cell lines. Transporters studied were BCRP, MDR1, MRP1, OATP1A5/OATP1A2, OCTN1 and OCT1. Gene expressions of BCRP and OCT1 in murine mammary glands were increased during gestation and lactation, whereas MDR1, MRP1, OATP1A5 and OCTN1 were decreased, compared to expressions in virgins. All transporters measured in mammary glands of mice were detected in bovine mammary tissue and in HC11 cells, while only MDR1 and MRP1 were detected in BME-UV cells. Prochloraz treatment induced MDR1 gene and protein expression in both differentiated HC11 and BME-UV cells and increased protein function in HC11 cells, resulting in decreased accumulation of the MDR1 substrate digoxin. In conclusion, our results demonstrate that murine (HC11) and bovine (BME-UV) mammary epithelial cells can be applied to characterize expression and function of transporters as well as effects of contaminants on the mammary transporters. An altered expression, induced by a drug or toxic chemical, on any of the transporters expressed in the mammary epithelial cells during lactation may modulate the well-balanced composition of nutrients and/or secretion of contaminants in milk with potential adverse effects on breast-fed infants and dairy consumers.
Collapse
Affiliation(s)
- Yagmur Yagdiran
- Department of Biomedical Sciences and Veterinary Public Health, Swedish University of Agricultural Sciences, SE-750 07 Uppsala, Sweden
| | - Agneta Oskarsson
- Department of Biomedical Sciences and Veterinary Public Health, Swedish University of Agricultural Sciences, SE-750 07 Uppsala, Sweden
| | - Christopher H. Knight
- Department of Veterinary Clinical and Animal Sciences, University of Copenhagen, 1870 Frederiksberg C, Denmark
| | - Jonas Tallkvist
- Department of Biomedical Sciences and Veterinary Public Health, Swedish University of Agricultural Sciences, SE-750 07 Uppsala, Sweden
- * E-mail:
| |
Collapse
|
10
|
Michalec K, Mysiorek C, Kuntz M, Bérézowski V, Szczepankiewicz AA, Wilczyński GM, Cecchelli R, Nałęcz KA. Protein kinase C restricts transport of carnitine by amino acid transporter ATB(0,+) apically localized in the blood-brain barrier. Arch Biochem Biophys 2014; 554:28-35. [PMID: 24823859 DOI: 10.1016/j.abb.2014.05.006] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2014] [Revised: 04/29/2014] [Accepted: 05/03/2014] [Indexed: 10/25/2022]
Abstract
Carnitine (3-hydroxy-4-trimethylammoniobutyrate) is necessary for transfer of fatty acids through the inner mitochondrial membrane. Carnitine, not synthesized in the brain, is delivered there through the strongly polarized blood-brain barrier (BBB). Expression and presence of two carnitine transporters - organic cation/carnitine transporter (OCTN2) and amino acid transporter B(0,+) (ATB(0,+)) have been demonstrated previously in an in vitro model of the BBB. Due to potential protein kinase C (PKC) phosphorylation sites within ATB(0,+) sequence, the present study verified effects of this kinase on transporter function and localization in the BBB. ATB(0,+) can be regulated by estrogen receptor α and up-regulated in vitro, therefore its presence in vivo was verified with the transmission electron microscopy. The analyses of brain slices demonstrated ATB(0,+) luminal localization in brain capillaries, confirmed by biotinylation experiments in an in vitro model of the BBB. Brain capillary endothelial cells were shown to control carnitine gradient. ATB(0,+) was phosphorylated by PKC, what correlated with inhibition of carnitine transport. PKC activation did not change the amount of ATB(0,+) present in the apical membrane of brain endothelial cells, but resulted in transporter exclusion from raft microdomains. ATB(0,+) inactivation by a lateral movement in plasma membrane after transporter phosphorylation has been postulated.
Collapse
Affiliation(s)
- Katarzyna Michalec
- Laboratory of Mechanisms of Transport Through Biomembranes, Nencki Institute of Experimental Biology, Warsaw, Poland
| | - Caroline Mysiorek
- Univ Lille Nord de France, Lille, France; UArtois, LBHE, Lens, France; IMPRT-IFR114, Lille, France
| | - Mélanie Kuntz
- Univ Lille Nord de France, Lille, France; UArtois, LBHE, Lens, France; IMPRT-IFR114, Lille, France
| | - Vincent Bérézowski
- Univ Lille Nord de France, Lille, France; UArtois, LBHE, Lens, France; IMPRT-IFR114, Lille, France
| | - Andrzej A Szczepankiewicz
- Laboratory of Molecular and Systemic Neuromorphology, Nencki Institute of Experimental Biology, Warsaw, Poland
| | - Grzegorz M Wilczyński
- Laboratory of Molecular and Systemic Neuromorphology, Nencki Institute of Experimental Biology, Warsaw, Poland
| | - Roméo Cecchelli
- Univ Lille Nord de France, Lille, France; UArtois, LBHE, Lens, France; IMPRT-IFR114, Lille, France
| | - Katarzyna A Nałęcz
- Laboratory of Mechanisms of Transport Through Biomembranes, Nencki Institute of Experimental Biology, Warsaw, Poland.
| |
Collapse
|
11
|
Shennan DB, Boyd CAR. The functional and molecular entities underlying amino acid and peptide transport by the mammary gland under different physiological and pathological conditions. J Mammary Gland Biol Neoplasia 2014; 19:19-33. [PMID: 24158403 DOI: 10.1007/s10911-013-9305-5] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/29/2013] [Accepted: 10/15/2013] [Indexed: 12/20/2022] Open
Abstract
This review describes the properties and regulation of the membrane transport proteins which supply the mammary gland with aminonitrogen to support metabolism under different physiological conditions (i.e. pregnancy, lactation and involution). Early studies focussed on characterising amino acid and peptide transport pathways with respect to substrate specificity, kinetics and hormonal regulation to allow a broad picture of the systems within the gland to be established. Recent investigations have concentrated on identifying the individual transporters at the molecular level (i.e. mRNA and protein). Many of the latter studies have identified the molecular correlates of the transport systems uncovered in the earlier functional investigations but in turn have also highlighted the need for more amino acid transport studies to be performed. The transporters function as either cotransporters and exchangers (or both) and act in a coordinated and regulated fashion to support the metabolic needs of the gland. However, it is apparent that a physiological role for a number of the transport proteins has yet to be elucidated. This article highlights the many gaps in our knowledge regarding the precise cellular location of a number of amino acid transporters within the gland. We also describe the role of amino acid transport in mammary cell volume regulation. Finally, the important role that individual mammary transport proteins may have in the growth and proliferation of mammary tumours is discussed.
Collapse
Affiliation(s)
- D B Shennan
- Brasenose College, 39 Caerlaverock Road, Prestwick, UK,
| | | |
Collapse
|
12
|
Koepsell H. The SLC22 family with transporters of organic cations, anions and zwitterions. Mol Aspects Med 2013; 34:413-35. [PMID: 23506881 DOI: 10.1016/j.mam.2012.10.010] [Citation(s) in RCA: 275] [Impact Index Per Article: 25.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2012] [Accepted: 08/18/2012] [Indexed: 12/14/2022]
Abstract
The SLC22 family contains 13 functionally characterized human plasma membrane proteins each with 12 predicted α-helical transmembrane domains. The family comprises organic cation transporters (OCTs), organic zwitterion/cation transporters (OCTNs), and organic anion transporters (OATs). The transporters operate as (1) uniporters which mediate facilitated diffusion (OCTs, OCTNs), (2) anion exchangers (OATs), and (3) Na(+)/zwitterion cotransporters (OCTNs). They participate in small intestinal absorption and hepatic and renal excretion of drugs, xenobiotics and endogenous compounds and perform homeostatic functions in brain and heart. Important endogeneous substrates include monoamine neurotransmitters, l-carnitine, α-ketoglutarate, cAMP, cGMP, prostaglandins, and urate. It has been shown that mutations of the SLC22 genes encoding these transporters cause specific diseases like primary systemic carnitine deficiency and idiopathic renal hypouricemia and are correlated with diseases such as Crohn's disease and gout. Drug-drug interactions at individual transporters may change pharmacokinetics and toxicities of drugs.
Collapse
Affiliation(s)
- Hermann Koepsell
- University of Würzburg, Institute of Anatomy and Cell Biology, Koellikerstr. 6, 97070 Würzburg, Germany.
| |
Collapse
|
13
|
Nirmal J, Singh SB, Biswas NR, Thavaraj V, Azad RV, Velpandian T. Potential pharmacokinetic role of organic cation transporters in modulating the transcorneal penetration of its substrates administered topically. Eye (Lond) 2013; 27:1196-203. [PMID: 23846373 DOI: 10.1038/eye.2013.146] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2013] [Accepted: 05/24/2013] [Indexed: 01/11/2023] Open
Abstract
PURPOSE We hypothesize organic cation transporters (OCT) may have a potential role in determining the pharmacokinetics and toxicity of organic cation drugs applied topically. Hence, in the present in vivo study, we attempted to evaluate the role of OCT in modulating the transport of its substrates after topical application. METHODS New Zealand albino rabbits of either sex were used. Transcorneal penetration of OCT substrates tetraethylammonium and metformin after single instillation was evaluated in the absence and presence of OCT blockers (quinidine and atropine). Aqueous humor (AH) samples were collected through paracentesis amounting to 70-100 μl under topical anesthesia at various time intervals. The samples were subjected for estimation of both substrate as well as blocker concentrations using liquid chromatography mass spectrometry. RESULTS Topical pre-treatment (30 min before substrate) of OCT blockers significantly decreased the transcorneal penetration of OCT substrates after single topical administration. The levels of blockers reaching AH in the presence of substrates were also modulated at 60 min after its administration as compared with its control. CONCLUSION OCT are functionally active in the uptake of their substrates from tear to AH. Therefore, OCT in the corneal epithelium may be positioned from apical to basolateral. When administering their substrates/blockers topically, both may be competing for OCT for their uptake across the cornea, thereby decreasing the corneal penetration. Hence OCT can have a potential pharmacokinetic role in modulating the ocular bioavailability of their substrates administered topically, which are used as ocular therapeutics.
Collapse
Affiliation(s)
- J Nirmal
- Department of Ocular Pharmacology and Pharmacy, Dr Rajendra Prasad Centre for Ophthalmic Sciences, All India Institute of Medical Sciences, Ansari Nagar, New Delhi, India
| | | | | | | | | | | |
Collapse
|
14
|
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.
Collapse
Affiliation(s)
- Ikumi Tamai
- Faculty of Pharmaceutical Sciences, Institute of Medical, Pharmaceutical and Health Sciences, Kanazawa University, Kanazawa, 920-1192, Japan.
| |
Collapse
|
15
|
Wu W, Dnyanmote AV, Nigam SK. Remote communication through solute carriers and ATP binding cassette drug transporter pathways: an update on the remote sensing and signaling hypothesis. Mol Pharmacol 2011; 79:795-805. [PMID: 21325265 DOI: 10.1124/mol.110.070607] [Citation(s) in RCA: 93] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Recent data from knockouts, human disease, and transport studies suggest that solute carrier (SLC) and ATP binding cassette (ABC) multispecific "drug" transporters maintain effective organ and body fluid concentrations of key nutrients, signaling molecules, and antioxidants. These processes involve transcellular movement of solutes across epithelial barriers and fluid compartments (e.g., blood, cerebrospinal fluid, urine, bile) via "matching" or homologous sets of SLC (e.g., SLC21, SLC22, SLC47) and ABC transporters. As described in the "Remote Sensing and Signaling Hypothesis" (Biochem Biophys Res Commun 323:429-436, 2004; Biochem Biophys Res Commun 351:872-876, 2006; J Biol Chem 282:23841-23853, 2007; Nat Clin Pract Nephrol 3:443-448, 2007; Mol Pharmacol 76:481-490, 2009), highly regulated transporter networks with overlapping substrate preferences are involved in sensing and signaling to maintain homeostasis in response to environmental changes (e.g., substrate imbalance and injury). They function in parallel with (and interact with) the endocrine and autonomic systems. Uric acid (urate), carnitine, prostaglandins, conjugated sex steroids, cGMP, odorants, and enterobiome metabolites are discussed here as examples. Xenobiotics hitchhike on endogenous carrier systems, sometimes leading to toxicity and side effects. By regulation of the expression and/or function of various remote organ multispecific transporters after injury, the overall transport capacity of the remote organ to handle endogenous toxins, metabolites, and signaling molecules may change, aiding in recovery. Moreover, these transporters may play a role in communication between organisms. The specific cellular components involved in sensing and altering transporter abundance or functionality depend upon the metabolite in question and probably involve different types of sensors as well as epigenetic regulation.
Collapse
Affiliation(s)
- Wei Wu
- Department of Medicine, University of California San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA
| | | | | |
Collapse
|
16
|
Upregulation of mammary gland OCTNs maintains carnitine homeostasis in suckling infants. Biochem Biophys Res Commun 2011; 404:1010-5. [DOI: 10.1016/j.bbrc.2010.12.100] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2010] [Accepted: 12/20/2010] [Indexed: 11/23/2022]
|
17
|
Eichhorst J, Alcorn J, Lepage J, Etter M, Antonishyn NA, Fitterer B, Birch DA, Agopsowicz KL, Ruthnum L, Greenberg CR, Lehotay DC. Elevated neonatal 3-OH isovalerylcarnitine due to breast milk sources in maternal 3-MCC deficiency. Mol Genet Metab 2010; 101:84-6. [PMID: 20619711 DOI: 10.1016/j.ymgme.2010.05.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/21/2010] [Accepted: 05/21/2010] [Indexed: 10/19/2022]
Abstract
We report a positive newborn screen for 3-hydroxyisovalerylcarnitine (C(5)OH) with an absence of 3-methylcrotonyl-coenzyme A carboxylase deficiency in the neonate. Subsequent blood tests demonstrated persistently elevated C(5)OH. Serial testing of the mother identified markedly elevated C(5)OH in both maternal blood and breast milk. High C(5)OH milk concentrations provide a significant source of C(5)OH to the nursing neonate and possibly explains its persistent elevation in the neonate, a commonly observed finding in maternal 3-MCC deficiency.
Collapse
Affiliation(s)
- Jeff Eichhorst
- Department of Pathology, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
18
|
High Affinity Carnitine Transporters from OCTN Family in Neural Cells. Neurochem Res 2010; 35:743-8. [DOI: 10.1007/s11064-010-0131-5] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/22/2010] [Indexed: 12/30/2022]
|
19
|
Ling B, Alcorn J. Acute administration of cefepime lowers L-carnitine concentrations in early lactation stage rat milk. J Nutr 2008; 138:1317-22. [PMID: 18567754 DOI: 10.1093/jn/138.7.1317] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Our study investigated the potential for important in vivo drug-nutrient transport interactions at the lactating mammary gland using the L-carnitine transporter substrates, cefepime and L-carnitine, as proof-of-concept. On d 4 (n = 6/treatment) and d 10 (n = 6/treatment) of lactation, rats were administered cefepime (250 mg/h) or saline by continuous i.v. infusion (4 h). Serum and milk L-carnitine and cefepime concentrations were quantified by HPLC-UV. In whole mammary gland, organic cation/carnitine transporter (OCTN)1, OCTN2, OCTN3, amino acid transporter B(0,+) (ATB(0,+)), and L-carnitine transporter 2 expression were determined by quantitative RT-PCR and by western blot and immunohistochemistry when possible. Cefepime caused a 56% decrease in milk L-carnitine concentrations on lactation d 4 (P = 0.0048) but did not affect milk L-carnitine at lactation d 10 or serum L-carnitine concentrations at either time. The mean L-carnitine and cefepime milk:serum ratios (M/S) decreased from 9.1 +/- 0.4 to 4.9 +/- 0.6 (P < 0.0001) and 0.89 +/- 0.3 to 0.12 +/- 0.02 (P = 0.0473), respectively, between d 4 and d 10 of lactation. In both groups, OCTN2 (P < 0.0001), OCTN3 (P = 0.0039), and ATB(0,+) (P = 0.004) mRNA expression and OCTN2 protein (P < 0.0001) were higher in mammary glands at d 4 of lactation compared with d 10. Immunohistochemistry revealed OCTN1 and OCTN2 localization in the mammary alveolar epithelium and OCTN3 expression in the interstitial space and blood vessel endothelium. In conclusion, cefepime significantly decreased milk L-carnitine concentrations only at d 4 of lactation. Relative to d 10, enhanced expression of OCTN2 and ATB(0,+) in mammary glands at d 4 of lactation and higher M/S (L-carnitine and cefepime) suggests cefepime competes with L-carnitine for L-carnitine transporters expressed in the lactating mammary gland to adversely affect L-carnitine milk concentrations and these effects depend upon lactation stage.
Collapse
Affiliation(s)
- Binbing Ling
- College of Pharmacy and Nutrition, University of Saskatchewan, Saskatoon, SK, S7N 5C9 Canada
| | | |
Collapse
|
20
|
Miecz D, Januszewicz E, Czeredys M, Hinton BT, Berezowski V, Cecchelli R, Nałecz KA. Localization of organic cation/carnitine transporter (OCTN2) in cells forming the blood-brain barrier. J Neurochem 2007; 104:113-23. [PMID: 17995936 DOI: 10.1111/j.1471-4159.2007.05024.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Carnitine beta-hydroxy-gamma-(trimethylammonio)butyrate - a compound necessary in the peripheral tissues for a transfer of fatty acids for their oxidation within the cell, accumulates in the brain despite low beta-oxidation in this organ. In order to enter the brain, carnitine has to cross the blood-brain barrier formed by capillary endothelial cells which are in close interaction with astrocytes. Previous studies, demonstrating expression of mRNA coding two carnitine transporters - organic cation/carnitine transporter 2 (OCTN2) and B(0,+) in endothelial cells, did not give any information on carnitine transporters polarity in endothelium. Therefore more detailed experiments were performed on expression and localization of a high affinity carnitine transporter OCTN2 in an in vitro model of the blood-brain barrier by real-time PCR, western blot analysis, and immunocytochemistry. The amount of mRNA was comparable in endothelial cells and kidney, when referred to house-keeping genes, it was, however, significantly lower in astrocytes. Polarity of OCTN2 localization was further studied in an in vitro model of the blood-brain barrier with use of anti-OCTN2 antibodies. Z-axis analysis of the confocal microscope pictures of endothelial cells, with anti-P-glycoprotein antibodies as the marker of apical membrane, showed OCTN2 localization at the basolateral membrane and in the cytoplasmic region in the vicinity of nuclei. Localization of OCTN2 suggest that carnitine can be also transported from the brain, playing an important role in removal of certain acyl esters.
Collapse
Affiliation(s)
- Dorota Miecz
- Nencki Institute of Experimental Biology, Warszawa, Poland
| | | | | | | | | | | | | |
Collapse
|