1
|
Catarina Duarte A, Raquel Costa A, Gonçalves I, Quintela T, Preissner R, R A Santos C. The druggability of bitter taste receptors for the treatment of neurodegenerative disorders. Biochem Pharmacol 2022; 197:114915. [PMID: 35051386 DOI: 10.1016/j.bcp.2022.114915] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2021] [Revised: 01/05/2022] [Accepted: 01/10/2022] [Indexed: 12/14/2022]
Abstract
The delivery of therapeutic drugs to the brain remains a major pharmacology challenge. A complex system of chemical surveillance to protect the brain from endogenous and exogenous toxicants at brain barriers hinders the uptake of many compounds with significant in vitro and ex vivo therapeutic properties. Despite the advances in the field in recent years, the components of this system are not completely understood. Recently, a large group of chemo-sensing receptors, have been identified in the blood-cerebrospinal fluid barrier. Among these chemo-sensing receptors, bitter taste receptors (TAS2R) hold promise as potential drug targets, as many TAS2R bind compounds with recognized neuroprotective activity (quercetin, resveratrol, among others). Whether activation of TAS2R by their ligands contributes to their diverse biological actions described in other cells and tissues is still debatable. In this review, we discuss the potential role of TAS2R gene family as the mediators of the biological activity of their ligands for the treatment of central nervous system disorders and discuss their potential to counteract drug resistance by improving drug delivery to the brain.
Collapse
Affiliation(s)
- Ana Catarina Duarte
- CICS-UBI - Health Sciences Research Center, University of Beira Interior, Covilhã, Portugal; CPIRN-IPG- Centro de Potencial e Inovação de Recursos Naturais- Instituto Politécnico da Guarda, Av. Dr. Francisco de Sá Carneiro, 6300-559, Guarda, Portugal
| | - Ana Raquel Costa
- CICS-UBI - Health Sciences Research Center, University of Beira Interior, Covilhã, Portugal
| | - Isabel Gonçalves
- CICS-UBI - Health Sciences Research Center, University of Beira Interior, Covilhã, Portugal
| | - Telma Quintela
- CICS-UBI - Health Sciences Research Center, University of Beira Interior, Covilhã, Portugal
| | - Robert Preissner
- Institute of Physiology and Science-IT, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Philippstrasse 12, 10115, Berlin, Germany
| | - Cecília R A Santos
- CICS-UBI - Health Sciences Research Center, University of Beira Interior, Covilhã, Portugal.
| |
Collapse
|
2
|
Duarte AC, Rosado T, Costa AR, Santos J, Gallardo E, Quintela T, Ishikawa H, Schwerk C, Schroten H, Gonçalves I, Santos CRA. The bitter taste receptor TAS2R14 regulates resveratrol transport across the human blood-cerebrospinal fluid barrier. Biochem Pharmacol 2020; 177:113953. [PMID: 32272108 DOI: 10.1016/j.bcp.2020.113953] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2020] [Accepted: 03/31/2020] [Indexed: 02/06/2023]
Abstract
The regulation of transport mechanisms at brain barriers must be thoroughly understood, so that novel strategies for improving drug delivery to the brain can be designed. The blood-cerebrospinal fluid barrier (BCSFB) established by the choroid plexus (CP) epithelial cells has been poorly studied in this regard despite its relevance for the protection of the central nervous system (CNS). This study assessed the role of bitter taste receptors (TAS2Rs), TAS2R14 and TAS2R39, in the transport of resveratrol across CP epithelial cells using an in vitro model of the human BCSFB. Both receptors are expressed in human CP cells and known to bind resveratrol. First, Ca2+ imaging assays demonstrated that resveratrol specifically activates the TAS2R14 receptor, but not TAS2R39, in these human CP epithelial cells. Then, we proceeded with permeation studies that showed resveratrol can cross the human BCSFB, from the blood to the CSF side and that TAS2R14 knockdown decreased the transport of resveratrol across these cells. Conversely, inhibition of efflux transporters ABCC1, ABCC4 or ABCG2 also restrained the transport of resveratrol across these cells. Interestingly, resveratrol upregulated the expression of ABCG2 located at the apical membrane of the cells via TAS2R14, whereas ABCC1 and ABCC4 at the basolateral membrane of the cells were not affected. Altogether, our study demonstrates that the BCSFB is a gateway for resveratrol entrance into the CNS and that the receptor TAS2R14 regulates its transport by regulating the action of efflux transporters at CP epithelial cells.
Collapse
Affiliation(s)
- Ana C Duarte
- CICS-UBI - Health Sciences Research Centre, Universidade da Beira Interior, Covilhã, Portugal
| | - Tiago Rosado
- CICS-UBI - Health Sciences Research Centre, Universidade da Beira Interior, Covilhã, Portugal; Laboratório de Fármaco-Toxicologia, UBIMedical, Universidade da Beira Interior, Estrada Municipal 506, 6200-284 Covilhã, Portugal
| | - Ana R Costa
- CICS-UBI - Health Sciences Research Centre, Universidade da Beira Interior, Covilhã, Portugal
| | - José Santos
- CICS-UBI - Health Sciences Research Centre, Universidade da Beira Interior, Covilhã, Portugal
| | - Eugénia Gallardo
- CICS-UBI - Health Sciences Research Centre, Universidade da Beira Interior, Covilhã, Portugal; Laboratório de Fármaco-Toxicologia, UBIMedical, Universidade da Beira Interior, Estrada Municipal 506, 6200-284 Covilhã, Portugal
| | - Telma Quintela
- CICS-UBI - Health Sciences Research Centre, Universidade da Beira Interior, Covilhã, Portugal
| | - Hiroshi Ishikawa
- Laboratory of Clinical Regenerative Medicine, Department of Neurosurgery, Faculty of Medicine, University of Tsukuba, Tsukuba, Japan
| | - Christian Schwerk
- Pediatric Infectious Diseases, Department of Pediatrics, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
| | - Horst Schroten
- Pediatric Infectious Diseases, Department of Pediatrics, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
| | - Isabel Gonçalves
- CICS-UBI - Health Sciences Research Centre, Universidade da Beira Interior, Covilhã, Portugal
| | - Cecília R A Santos
- CICS-UBI - Health Sciences Research Centre, Universidade da Beira Interior, Covilhã, Portugal.
| |
Collapse
|
3
|
Synthesis of bifunctional cabbage flower-like Ho 3+/NiO nanostructures as a modifier for simultaneous determination of methotrexate and carbamazepine. Anal Bioanal Chem 2020; 412:1011-1024. [PMID: 31897563 DOI: 10.1007/s00216-019-02326-8] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2019] [Revised: 11/15/2019] [Accepted: 12/03/2019] [Indexed: 10/25/2022]
Abstract
Cabbage flower-like Ho3+/NiO nanostructure (CFL-Ho3+/NiO NSs) with significant electrocatalytic oxidation has been published for the first time. First, structure and morphology of CFL-Ho3+/NiO-NSs have been described by XRD, SEM, and EDX methods. Then, CFL-Ho3+/NiO-NSs have been applied as a modifier for simultaneous electrochemical detection of methotrexate (MTX) and carbamazepine (CBZ). Functions of the modified electrode have been dealt with through electrochemical impedance spectroscopy (EIS). It has been demonstrated that the electrode response has been linear from 0.001-310.0 μM with a limit of detection of 5.2 nM and 4.5 nM (3 s/m) through DPV for MTX and CBZ. Diffusion coefficient (D) and heterogeneous rate constant (kh) have been detected for MTX and CBZ oxidation at the surface of the modified electrode. Moreover, CFL-Ho3+/NiO-NS/GCE has been employed for determining MTX and CBZ in urine and drug specimens. Outputs showed the analyte acceptable recovery. Therefore, the electrode could be applied to analyze both analytes in drug prescription and clinical laboratories. Graphical abstract Electrochemical sensor based on bifunctional cabbage flower-like Ho3+/NiO nanostructures modified glassy carbon electrode for simultaneous detecting methotrexate and carbamazepine was fabricated.
Collapse
|
4
|
Vidmar M, Grželj J, Mlinarič-Raščan I, Geršak K, Dolenc MS. Medicines associated with folate-homocysteine-methionine pathway disruption. Arch Toxicol 2018; 93:227-251. [PMID: 30499019 DOI: 10.1007/s00204-018-2364-z] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2018] [Accepted: 11/20/2018] [Indexed: 12/18/2022]
Abstract
Folate is vital for cell development and growth. It is involved in one-carbon transfer reactions essential for the synthesis of purines and pyrimidines. It also acts in conjunction with cobalamin (vitamin B12) as a fundamental cofactor in the remethylation cycle that converts homocysteine to methionine. A deficiency in folate or vitamin B12 can lead to elevated homocysteine level, which has been identified as an independent risk factor in several health-related conditions. Adequate folate levels are essential in women of childbearing age and in pregnant women, and folate deficiency is associated with several congenital malformations. Low folate levels can be caused by dietary deficiencies, a genetic predisposition or treatment with medicines that affect folate concentration. Women who are pregnant or of child-bearing age commonly use medicines, so it is important to identify the basic biochemical mechanisms by which medicines interfere with the folate-homocysteine-methionine pathway. This review focuses on prescription medicines associated with folate disruption. It also summarizes their undesirable/toxic effects. Recommendations regarding folate supplementation during medical therapy are also reviewed.
Collapse
Affiliation(s)
- M Vidmar
- Research Unit, Department of Obstetrics and Gynecology, University Medical Centre Ljubljana, Šlajmarjeva 3, Ljubljana, Slovenia.,University of Ljubljana, Faculty of Pharmacy, Aškerčeva 7, Ljubljana, Slovenia
| | - J Grželj
- University of Ljubljana, Faculty of Pharmacy, Aškerčeva 7, Ljubljana, Slovenia.,Krka, d.d., Novo mesto, Šmarješka 6, Novo mesto, Slovenia
| | - I Mlinarič-Raščan
- University of Ljubljana, Faculty of Pharmacy, Aškerčeva 7, Ljubljana, Slovenia
| | - K Geršak
- Research Unit, Department of Obstetrics and Gynecology, University Medical Centre Ljubljana, Šlajmarjeva 3, Ljubljana, Slovenia
| | - M Sollner Dolenc
- University of Ljubljana, Faculty of Pharmacy, Aškerčeva 7, Ljubljana, Slovenia.
| |
Collapse
|
5
|
Ogushi N, Sasaki K, Shimoda M. Effects of leucovorin (folinic acid) in the methotrexate-treated rat brain. J Vet Med Sci 2018; 80:760-765. [PMID: 29607891 PMCID: PMC5989019 DOI: 10.1292/jvms.17-0666] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
Folinic acid (FA) is generally administered to patients with CNS tumors in order to treat severe neurological disorders caused by methotrexate (MTX); therefore, we herein examined the
effects of the co-administration of FA on MTX concentrations in the rat brain and cerebrospinal fluid (CSF) as well as the pharmacokinetics of MTX. MTX was intravenously or intrathecally
administered to rats with or without FA. MTX concentrations were assessed by HPLC. No significant differences were observed in pharmacokinetic parameters, including kel,
Vd, AUC, Cltot and t1/2, between the FA-treated and non-treated groups. MTX concentrations were not significantly different in the brain or CSF 6 hr after
the intrathecal administration of MTX. However, compare to intravenous administration of MTX, intravenous administration of both FA and MTX significantly decreased MTX concentrations in the
brains and CSF. These results suggest that FA inhibits the influx of MTX into the brain and CSF, possibly by competing with folate carriers, but has no effect on its efflux from these
regions. Therefore, FA may be administered to CNS tumor patients receiving intrathecal MTX therapy in order to treat the adverse effects of MTX without affecting its concentrations in the
brain and CSF.
Collapse
Affiliation(s)
- Naofumi Ogushi
- The Department of Veterinary Medicine, Faculty of Agriculture, Tokyo University of Agriculture and Technology, Fuchu, Tokyo 183-8509, Japan.,Ogushi Animal Hospital, 3-2556-5 Wakasa Tokorozawa-shi, Saitama 359-1151, Japan
| | - Kazuaki Sasaki
- The Department of Veterinary Medicine, Faculty of Agriculture, Tokyo University of Agriculture and Technology, Fuchu, Tokyo 183-8509, Japan
| | - Minoru Shimoda
- The Department of Veterinary Medicine, Faculty of Agriculture, Tokyo University of Agriculture and Technology, Fuchu, Tokyo 183-8509, Japan
| |
Collapse
|
6
|
Mann A, Portnoy E, Han H, Inbar D, Blatch D, Shmuel M, Ben-Hur T, Eyal S, Ekstein D. Folate homeostasis in epileptic rats. Epilepsy Res 2018; 142:64-72. [PMID: 29571151 DOI: 10.1016/j.eplepsyres.2018.03.014] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2018] [Revised: 03/09/2018] [Accepted: 03/15/2018] [Indexed: 12/28/2022]
Abstract
Folate is involved in metabolic processes and it has been implicated in both aggravation and amelioration of seizures. The aim of the current work was to study the effect of chronic temporal lobe epilepsy (TLE) on the plasma and brain concentrations of folate and on its uptake carriers in the brain - the reduced folate carrier (RFC), folate receptor α (FRα) and proton coupled folate transporter (PCFT). We utilized the rat lithium pilocarpine model for TLE. Approximately two months following status epilepticus, rats with spontaneous recurrent seizures (SRS) were sacrificed for brain and plasma folate concentration analyses and folate uptake carrier expression studies. RT-PCR and western blot analyses were utilized for quantification of folate carriers' mRNAs and proteins, respectively. The distribution of folate carriers in the brain was studied using immunohistochemistry. In the SRS rats we found lower plasma concentrations (10 ± 0.9 in control vs. 6.6 ± 1.6 ng/ml in SRS, P < 0.05), but preserved cortical and increased hippocampal levels of folate (0.5 ± 0.1 in control vs. 0.9 ± 0.2 ng/mg in SRS, P = 0.055). Hippocampus - to - plasma ratio of folate concentration was 3-fold higher in the SRS group, compared with the controls (0.13 ± 0.03 vs. 0.04 ± 0.02, respectively; P < 0.01). mRNA and protein levels of the folate uptake carriers did not differ between SRS rats and controls. However, immunofluorescent staining quantification revealed that the emission intensity of both RFC and FRα was elevated 8-fold and 4-fold, respectively, in hippocampal CA1 neurons of SRS rats, compared to controls (P < 0.01). PCFT was unquantifiable. If corroborated by complementary research in humans, the findings of this study may be utilized clinically for supplemental therapy planning, in imaging the epileptic focus, and for drug delivery into the epileptic brain. Further studies are required for better elucidating the clinical and mechanistic significance of altered folate balances in the epileptic brain.
Collapse
Affiliation(s)
- Aniv Mann
- Institute for Drug Research, School of Pharmacy, The Hebrew University of Jerusalem, Jerusalem, 91120 Israel.
| | - Emma Portnoy
- Institute for Drug Research, School of Pharmacy, The Hebrew University of Jerusalem, Jerusalem, 91120 Israel.
| | - Hadas Han
- Institute for Drug Research, School of Pharmacy, The Hebrew University of Jerusalem, Jerusalem, 91120 Israel.
| | - Dorrit Inbar
- Department of Neurology, Agnes Ginges Center for Human Neurogenetics, Hadassah Hebrew University Medical Center, Jerusalem, 91120, Israel.
| | - Dana Blatch
- Department of Neurology, Agnes Ginges Center for Human Neurogenetics, Hadassah Hebrew University Medical Center, Jerusalem, 91120, Israel.
| | - Miriam Shmuel
- Institute for Drug Research, School of Pharmacy, The Hebrew University of Jerusalem, Jerusalem, 91120 Israel.
| | - Tamir Ben-Hur
- Department of Neurology, Agnes Ginges Center for Human Neurogenetics, Hadassah Hebrew University Medical Center, Jerusalem, 91120, Israel.
| | - Sara Eyal
- Institute for Drug Research, School of Pharmacy, The Hebrew University of Jerusalem, Jerusalem, 91120 Israel.
| | - Dana Ekstein
- Department of Neurology, Agnes Ginges Center for Human Neurogenetics, Hadassah Hebrew University Medical Center, Jerusalem, 91120, Israel.
| |
Collapse
|
7
|
Morris ME, Rodriguez-Cruz V, Felmlee MA. SLC and ABC Transporters: Expression, Localization, and Species Differences at the Blood-Brain and the Blood-Cerebrospinal Fluid Barriers. AAPS JOURNAL 2017; 19:1317-1331. [PMID: 28664465 DOI: 10.1208/s12248-017-0110-8] [Citation(s) in RCA: 101] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/25/2017] [Accepted: 06/05/2017] [Indexed: 12/11/2022]
Abstract
The blood-brain barrier (BBB) and the blood-cerebrospinal fluid barrier (BCSFB) separate the brain and cerebrospinal fluid (CSF) from the systemic circulation and represent a barrier to the uptake of both endogenous compounds and xenobiotics into the brain. For compounds whose passive diffusion is limited due to their ionization or hydrophilicity, membrane transporters can facilitate their uptake across the BBB or BCSFB. Members of the solute carrier (SLC) and ATP-binding case (ABC) families are present on these barriers. Differences exist in the localization and expression of transport proteins between the BBB and BCSFB, resulting in functional differences in transport properties. This review focuses on the expression, membrane localization, and different isoforms present at each barrier. Diseases that affect the central nervous system including brain tumors, HIV, Alzheimer's disease, Parkinson's disease, and stroke affect the integrity and expression of transporters at the BBB and BCSFB and will be briefly reviewed.
Collapse
Affiliation(s)
- Marilyn E Morris
- Department of Pharmaceutical Sciences, University at Buffalo, State University of New York at Buffalo, Buffalo, New York, 14214-8033, USA.
| | - Vivian Rodriguez-Cruz
- Department of Pharmaceutical Sciences, University at Buffalo, State University of New York at Buffalo, Buffalo, New York, 14214-8033, USA
| | - Melanie A Felmlee
- Department of Pharmaceutics and Medicinal Chemistry, Thomas J Long School of Pharmacy and Health Sciences, University of the Pacific, 3601 Pacific Ave, Stockton, California, 95211, USA
| |
Collapse
|
8
|
Bénit CP, Vecht CJ. Seizures and cancer: drug interactions of anticonvulsants with chemotherapeutic agents, tyrosine kinase inhibitors and glucocorticoids. Neurooncol Pract 2015; 3:245-260. [PMID: 31385988 DOI: 10.1093/nop/npv038] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2015] [Indexed: 01/13/2023] Open
Abstract
Patients with cancer commonly experience seizures. Combined therapy with anticonvulsant drugs (AEDs) and chemotherapeutic drugs or tyrosine kinase inhibitors carries inherent risks on drug-drug interactions (DDIs). In this review, pharmacokinetic studies of AEDs with chemotherapeutic drugs, tyrosine kinase inhibitors, and glucocorticoids are discussed, including data on maximum tolerated dose, drug clearance, elimination half-life, and organ exposure. Enzyme-inducing AEDs (EIAEDs) cause about a 2-fold to 3-fold faster clearance of concurrent chemotherapeutic drugs metabolized along the same pathway, including cyclophosphamide, irinotecan, paclitaxel, and teniposide, and up to 4-fold faster clearance with the tyrosine kinase inhibitors crizotinib, dasatinib, imatinib, and lapatinib. The use of tyrosine kinase inhibitors, particularly imatinib and crizotinib, may lead to enzyme inhibition of concurrent therapy. Many of the newer generation AEDs do not induce or inhibit drug metabolism, but they can alter enzyme activity by other drugs including AEDs, chemotherapeutics and tyrosine kinase inhibitors. Glucocorticoids can both induce and undergo metabolic change. Quantitative data on changes in drug metabolism help to apply the appropriate dose regimens. Because the large individual variability in metabolic activity increases the risks for undertreatment and/or toxicity, we advocate routine plasma drug monitoring. There are insufficient data available on the effects of tyrosine kinase inhibitors on AED metabolism.
Collapse
Affiliation(s)
- Christa P Bénit
- Department of Neurology, Medical Center Haaglanden, The Hague, Netherlands (C.B.); Service Neurologie Mazarin, GH Pitié-Salpêtrière, Paris, France (C.J.V.)
| | - Charles J Vecht
- Department of Neurology, Medical Center Haaglanden, The Hague, Netherlands (C.B.); Service Neurologie Mazarin, GH Pitié-Salpêtrière, Paris, France (C.J.V.)
| |
Collapse
|
9
|
Characterization of efflux transport proteins of the human choroid plexus papilloma cell line HIBCPP, a functional in vitro model of the blood-cerebrospinal fluid barrier. Pharm Res 2015; 32:2973-82. [PMID: 25986174 DOI: 10.1007/s11095-015-1679-1] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2014] [Accepted: 03/18/2015] [Indexed: 01/06/2023]
Abstract
PURPOSE To characterize the human choroid plexus (CP) papilloma cell line HIBCPP with respect to ABC export protein expression and function in order to evaluate its use as an in vitro model to study carrier-mediated transport processes at the CP. METHODS Expression profiles of ABC transporters were studied by quantitative real-time PCR and Western Blot analysis. Functionality of transporters was investigated by means of uptake experiments and permeation studies carried out on permeable filter systems. In addition, immunohistochemistry served to study localization of ABCC1 and ABCC4. RESULTS Both qPCR and Western Blot revealed that ABC transporters known to be expressed in CP are also expressed in HIBCPP cells. Immunohistochemistry confirmed basolateral expression of ABCC1. Functionality of ABCC1, ABCC4, ABCB1 and ABCG2 could be shown in uptake assays. CONCLUSIONS Altogether, the HIBCPP cells promise to be a functional and relevant in vitro tool to investigate transport processes at the blood-cerebrospinal fluid barrier.
Collapse
|
10
|
Sanchez-Covarrubias L, Slosky LM, Thompson BJ, Davis TP, Ronaldson PT. Transporters at CNS barrier sites: obstacles or opportunities for drug delivery? Curr Pharm Des 2014; 20:1422-49. [PMID: 23789948 DOI: 10.2174/13816128113199990463] [Citation(s) in RCA: 154] [Impact Index Per Article: 15.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2013] [Accepted: 06/18/2013] [Indexed: 01/11/2023]
Abstract
The blood-brain barrier (BBB) and blood-cerebrospinal fluid (BCSF) barriers are critical determinants of CNS homeostasis. Additionally, the BBB and BCSF barriers are formidable obstacles to effective CNS drug delivery. These brain barrier sites express putative influx and efflux transporters that precisely control permeation of circulating solutes including drugs. The study of transporters has enabled a shift away from "brute force" approaches to delivering drugs by physically circumventing brain barriers towards chemical approaches that can target specific compounds of the BBB and/or BCSF barrier. However, our understanding of transporters at the BBB and BCSF barriers has primarily focused on understanding efflux transporters that efficiently prevent drugs from attaining therapeutic concentrations in the CNS. Recently, through the characterization of multiple endogenously expressed uptake transporters, this paradigm has shifted to the study of brain transporter targets that can facilitate drug delivery (i.e., influx transporters). Additionally, signaling pathways and trafficking mechanisms have been identified for several endogenous BBB/BCSF transporters, thereby offering even more opportunities to understand how transporters can be exploited for optimization of CNS drug delivery. This review presents an overview of the BBB and BCSF barrier as well as the many families of transporters functionally expressed at these barrier sites. Furthermore, we present an overview of various strategies that have been designed and utilized to deliver therapeutic agents to the brain with a particular emphasis on those approaches that directly target endogenous BBB/BCSF barrier transporters.
Collapse
Affiliation(s)
| | | | | | | | - Patrick T Ronaldson
- Department of Medical Pharmacology, College of Medicine, University of Arizona, 1501 North Campbell Avenue, P.O. Box 245050, Tucson, AZ, 85724-5050.
| |
Collapse
|
11
|
Choroid plexus transcytosis and exosome shuttling deliver folate into brain parenchyma. Nat Commun 2013; 4:2123. [PMID: 23828504 DOI: 10.1038/ncomms3123] [Citation(s) in RCA: 221] [Impact Index Per Article: 20.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2013] [Accepted: 06/07/2013] [Indexed: 12/19/2022] Open
Abstract
Loss of folate receptor-α function is associated with cerebral folate transport deficiency and childhood-onset neurodegeneration. To clarify the mechanism of cerebral folate transport at the blood-cerebrospinal fluid barrier, we investigate the transport of 5-methyltetrahydrofolate in polarized cells. Here we identify folate receptor-α-positive intralumenal vesicles within multivesicular bodies and demonstrate the directional cotransport of human folate receptor-α, and labelled folate from the basolateral to the apical membrane in rat choroid plexus cells. Both the apical medium of folate receptor-α-transfected rat choroid plexus cells and human cerebrospinal fluid contain folate receptor-α-positive exosomes. Loss of folate receptor-α-expressing cerebrospinal fluid exosomes correlates with severely reduced 5-methyltetrahydrofolate concentration, corroborating the importance of the folate receptor-α-mediated folate transport in the cerebrospinal fluid. Intraventricular injections of folate receptor-α-positive and -negative exosomes into mouse brains demonstrate folate receptor-α-dependent delivery of exosomes into the brain parenchyma. Our results unravel a new pathway of folate receptor-α-dependent exosome-mediated folate delivery into the brain parenchyma and opens new avenues for cerebral drug targeting.
Collapse
|
12
|
Ho HTB, Dahlin A, Wang J. Expression Profiling of Solute Carrier Gene Families at the Blood-CSF Barrier. Front Pharmacol 2012; 3:154. [PMID: 22936914 PMCID: PMC3426838 DOI: 10.3389/fphar.2012.00154] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2012] [Accepted: 08/01/2012] [Indexed: 12/12/2022] Open
Abstract
The choroid plexus (CP) is a highly vascularized tissue in the brain ventricles and acts as the blood-cerebrospinal fluid (CSF) barrier (BCSFB). A main function of the CP is to secrete CSF, which is accomplished by active transport of small ions and water from the blood side to the CSF side. The CP also supplies the brain with certain nutrients, hormones, and metal ions, while removing metabolites and xenobiotics from the CSF. Numerous membrane transporters are expressed in the CP in order to facilitate the solute exchange between the blood and the CSF. The solute carrier (SLC) superfamily represents a major class of transporters in the CP that constitutes the molecular mechanisms for CP function. Recently, we systematically and quantitatively examined Slc gene expression in 20 anatomically comprehensive brain areas in the adult mouse brain using high-quality in situ hybridization data generated by the Allen Brain Atlas. Here we focus our analysis on Slc gene expression at the BCSFB using previously obtained data. Of the 252 Slc genes present in the mouse brain, 202 Slc genes were found at detectable levels in the CP. Unsupervised hierarchical cluster analysis showed that the CP Slc gene expression pattern is substantially different from the other 19 analyzed brain regions. The majority of the Slc genes in the CP are expressed at low to moderate levels, whereas 28 Slc genes are present in the CP at the highest levels. These highly expressed Slc genes encode transporters involved in CSF secretion, energy production, and transport of nutrients, hormones, neurotransmitters, sulfate, and metal ions. In this review, the functional characteristics and potential importance of these Slc transporters in the CP are discussed, with particular emphasis on their localization and physiological functions at the BCSFB.
Collapse
Affiliation(s)
- Horace T B Ho
- Department of Pharmaceutics, University of Washington Seattle, WA, USA
| | | | | |
Collapse
|
13
|
Sprowl JA, Mikkelsen TS, Giovinazzo H, Sparreboom A. Contribution of tumoral and host solute carriers to clinical drug response. Drug Resist Updat 2012; 15:5-20. [PMID: 22459901 DOI: 10.1016/j.drup.2012.01.009] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Members of the solute carrier family of transporters are responsible for the cellular uptake of a broad range of endogenous compounds and xenobiotics in multiple tissues. Several of these solute carriers are known to be expressed in cancer cells or cancer cell lines, and decreased cellular uptake of drugs potentially contributes to the development of resistance. As result, the expression levels of these proteins in humans have important consequences for an individual's susceptibility to certain drug-induced side effects, interactions, and treatment efficacy. In this review article, we provide an update of this rapidly emerging field, with specific emphasis on the direct contribution of solute carriers to anticancer drug uptake in tumors, the role of these carriers in regulation of anticancer drug disposition, and recent advances in attempts to evaluate these proteins as therapeutic targets.
Collapse
Affiliation(s)
- Jason A Sprowl
- Department of Pharmaceutical Sciences, St Jude Children's Research Hospital, Memphis, TN 38105, USA
| | | | | | | |
Collapse
|