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Sangha V, Aboulhassane S, Bendayan R. Regulation of folate transport at the mouse arachnoid barrier. Fluids Barriers CNS 2024; 21:67. [PMID: 39192328 DOI: 10.1186/s12987-024-00566-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2024] [Accepted: 08/13/2024] [Indexed: 08/29/2024] Open
Abstract
BACKGROUND Folates are a family of B9 vitamins essential for normal growth and development in the central nervous system (CNS). Transport of folates is mediated by three major transport proteins: folate receptor alpha (FRα), proton-coupled folate transporter (PCFT), and reduced folate carrier (RFC). Brain folate uptake occurs at the choroid plexus (CP) epithelium through coordinated actions of FRα and PCFT, or directly into brain parenchyma at the vascular blood-brain barrier (BBB), mediated by RFC. Impaired folate transport can occur due to loss of function mutations in FRα or PCFT, resulting in suboptimal CSF folate levels. Our previous reports have demonstrated RFC upregulation by nuclear respiratory factor-1 (NRF-1) once activated by the natural compound pyrroloquinoline quinone (PQQ). More recently, we have identified folate transporter localization at the arachnoid barrier (AB). The purpose of the present study was to further characterize folate transporters localization and function in AB cells, as well as their regulation by NRF-1/PGC-1α signaling and folate deficiency. METHODS In immortalized mouse AB cells, polarized localization of RFC and PCFT was assessed by immunocytochemical analysis, with RFC and PCFT functionality examined with transport assays. The effects of PQQ treatment on changes in RFC functional expression were also investigated. Mouse AB cells grown in folate-deficient conditions were assessed for changes in gene expression of the folate transporters, and other key transporters and tight junction proteins. RESULTS Immunocytochemical analysis revealed apical localization of RFC at the mouse AB epithelium, with PCFT localized on the basolateral side and within intracellular compartments. PQQ led to significant increases in RFC functional expression, mediated by activation of the NRF-1/PGC-1α signalling cascade. Folate deficiency led to significant increases in expression of RFC, MRP3, P-gp, GLUT1 and the tight junction protein claudin-5. CONCLUSION These results uncover the polarized expression of RFC and PCFT at the AB, with induction of RFC functional expression by activation of the NRF-1/PGC-1α signalling pathway and folate deficiency. These results suggest that the AB may contribute to the flow of folates into the CSF, representing an additional pathway when folate transport at the CP is impaired.
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Affiliation(s)
- Vishal Sangha
- Leslie Dan Faculty of Pharmacy, University of Toronto, Toronto, Canada
| | - Sara Aboulhassane
- Leslie Dan Faculty of Pharmacy, University of Toronto, Toronto, Canada
| | - Reina Bendayan
- Leslie Dan Faculty of Pharmacy, University of Toronto, Toronto, Canada.
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Huang C, Hoque MT, Qu QR, Henderson J, Bendayan R. Antiretroviral drug dolutegravir induces inflammation at the mouse brain barriers. FASEB J 2024; 38:e23790. [PMID: 38982638 DOI: 10.1096/fj.202400558r] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2024] [Revised: 06/05/2024] [Accepted: 06/24/2024] [Indexed: 07/11/2024]
Abstract
Integrase strand transfer inhibitors (INSTIs) based antiretroviral therapy (ART) is currently used as first-line regimen to treat HIV infection. Despite its high efficacy and barrier to resistance, ART-associated neuropsychiatric adverse effects remain a major concern. Recent studies have identified a potential interaction between the INSTI, dolutegravir (DTG), and folate transport pathways at the placental barrier. We hypothesized that such interactions could also occur at the two major blood-brain interfaces: blood-cerebrospinal fluid barrier (BCSFB) and blood-brain barrier (BBB). To address this question, we evaluated the effect of two INSTIs, DTG and bictegravir (BTG), on folate transporters and receptor expression at the mouse BCSFB and the BBB in vitro, ex vivo and in vivo. We demonstrated that DTG but not BTG significantly downregulated the mRNA and/or protein expression of folate transporters (RFC/SLC19A1, PCFT/SLC46A1) in human and mouse BBB models in vitro, and mouse brain capillaries ex vivo. Our in vivo study further revealed a significant downregulation in Slc19a1 and Slc46a1 mRNA expression at the BCSFB and the BBB following a 14-day DTG oral treatment in C57BL/6 mice. However, despite the observed downregulatory effect of DTG in folate transporters/receptor at both brain barriers, a 14-day oral treatment of DTG-based ART did not significantly alter the brain folate level in animals. Interestingly, DTG treatment robustly elevated the mRNA and/or protein expression of pro-inflammatory cytokines and chemokines (Cxcl1, Cxcl2, Cxcl3, Il6, Il23, Il12) in primary cultures of mouse brain microvascular endothelial cells (BBB). DTG oral treatment also significantly upregulated proinflammatory cytokines and chemokine (Il6, Il1β, Tnfα, Ccl2) at the BCSFB in mice. We additionally observed a downregulated mRNA expression of drug efflux transporters (Abcc1, Abcc4, and Abcb1a) and tight junction protein (Cldn3) at the CP isolated from mice treated with DTG. Despite the structural similarities, BTG only elicited minor effects on the markers of interest at both the BBB and BCSFB. In summary, our current data demonstrates that DTG but not BTG strongly induced inflammatory responses in a rodent BBB and BCSFB model. Together, these data provide valuable insights into the mechanism of DTG-induced brain toxicity, which may contribute to the pathogenesis of DTG-associated neuropsychiatric adverse effect.
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Affiliation(s)
- Chang Huang
- Department of Pharmaceutical Sciences, Leslie Dan Faculty of Pharmacy, University of Toronto, Toronto, Ontario, Canada
| | - Md Tozammel Hoque
- Department of Pharmaceutical Sciences, Leslie Dan Faculty of Pharmacy, University of Toronto, Toronto, Ontario, Canada
| | - Qing Rui Qu
- Department of Pharmaceutical Sciences, Leslie Dan Faculty of Pharmacy, University of Toronto, Toronto, Ontario, Canada
| | - Jeffrey Henderson
- Department of Pharmaceutical Sciences, Leslie Dan Faculty of Pharmacy, University of Toronto, Toronto, Ontario, Canada
| | - Reina Bendayan
- Department of Pharmaceutical Sciences, Leslie Dan Faculty of Pharmacy, University of Toronto, Toronto, Ontario, Canada
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Hou X, Lu Z, Yu T, Zhang Y, Yao Q, Zhang C, Niu Y, Liang Q. Two maize homologs of mammalian proton-coupled folate transporter, ZmMFS_1-62 and ZmMFS_1-73, are essential to salt and drought tolerance. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2024; 210:108623. [PMID: 38626656 DOI: 10.1016/j.plaphy.2024.108623] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/23/2024] [Revised: 03/31/2024] [Accepted: 04/08/2024] [Indexed: 04/18/2024]
Abstract
Folates are essential to the maintenance of normal life activities in almost all organisms. Proton-coupled folate transporter (PCFT), belonging to the major facilitator superfamily, is one of the three major folate transporter types widely studied in mammals. However, information about plant PCFTs is limited. Here, a genome-wide identification of maize PCFTs was performed, and two PCFTs, ZmMFS_1-62 and ZmMFS_1-73, were functionally investigated. Both proteins contained the typical 12 transmembrane helixes with N- and C-termini located in the cytoplasm, and were localized in the plasma membrane. Molecular docking analysis indicated their binding activity with folates via hydrogen bonding. Interference with ZmMFS_1-62 and ZmMFS_1-73 in maize seedlings through virus-induced gene silencing disrupted folate homeostasis, mainly in the roots, and reduced tolerance to drought and salt stresses. Moreover, a molecular chaperone protein, ZmHSP20, was found to interact with ZmMFS_1-62 and ZmMFS_1-73, and interference with ZmHSP20 in maize seedlings also led to folate disruption and increased sensitivity to drought and salt stresses. Overall, this is the first report of functional identification of maize PCFTs, which play essential roles in salt and drought stress tolerance, thereby linking folate metabolism with abiotic stress responses in maize.
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Affiliation(s)
- Xiaowan Hou
- Biotechnology Research Institute, Chinese Academy of Agricultural Science, Beijing 100081, China; Key Laboratory of Hainan Province for Postharvest Physiology and Technology of Tropical Horticultural Products, South Subtropical Crops Research Institute, Chinese Academy of Tropical Agricultural Sciences, Zhanjiang, China; Key Laboratory of Forage and Endemic Crop Biotechnology, Ministry of Education, School of Life Sciences, Inner Mongolia University, Hohhot, China.
| | - Zhiwei Lu
- Key Laboratory of Hainan Province for Postharvest Physiology and Technology of Tropical Horticultural Products, South Subtropical Crops Research Institute, Chinese Academy of Tropical Agricultural Sciences, Zhanjiang, China.
| | - Taifei Yu
- Hunan Provincial Key Laboratory of the Research and Development of Novel Pharmaceutical Preparations, the "Double-First Class" Application Characteristic Discipline of Hunan Province (Pharmaceutical Science), Changsha Medical University, Changsha 410219, China.
| | - Yuanyuan Zhang
- Biotechnology Research Institute, Chinese Academy of Agricultural Science, Beijing 100081, China; Key Laboratory of Hainan Province for Postharvest Physiology and Technology of Tropical Horticultural Products, South Subtropical Crops Research Institute, Chinese Academy of Tropical Agricultural Sciences, Zhanjiang, China.
| | - Quansheng Yao
- Key Laboratory of Hainan Province for Postharvest Physiology and Technology of Tropical Horticultural Products, South Subtropical Crops Research Institute, Chinese Academy of Tropical Agricultural Sciences, Zhanjiang, China.
| | - Chunyi Zhang
- Biotechnology Research Institute, Chinese Academy of Agricultural Science, Beijing 100081, China; National Nanfan Research Institute, Chinese Academy of Agricultural Sciences, Sanya, 572000, China.
| | - Yiding Niu
- Key Laboratory of Forage and Endemic Crop Biotechnology, Ministry of Education, School of Life Sciences, Inner Mongolia University, Hohhot, China.
| | - Qiuju Liang
- Biotechnology Research Institute, Chinese Academy of Agricultural Science, Beijing 100081, China; National Nanfan Research Institute, Chinese Academy of Agricultural Sciences, Sanya, 572000, China.
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Gurler G, Belder N, Beker MC, Sever-Bahcekapili M, Uruk G, Kilic E, Yemisci M. Reduced folate carrier 1 is present in retinal microvessels and crucial for the inner blood retinal barrier integrity. Fluids Barriers CNS 2023; 20:47. [PMID: 37328777 DOI: 10.1186/s12987-023-00442-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2022] [Accepted: 05/18/2023] [Indexed: 06/18/2023] Open
Abstract
BACKGROUND Reduced folate carrier 1 (RFC1; SLC19a1) is the main responsible transporter for the B9 family of vitamins named folates, which are essential for normal tissue growth and development. While folate deficiency resulted in retinal vasculopathy, the expression and the role of RFC1 in blood-retinal barrier (BRB) are not well known. METHODS We used whole mount retinas and trypsin digested microvessel samples of adult mice. To knockdown RFC1, we delivered RFC1-targeted short interfering RNA (RFC1-siRNA) intravitreally; while, to upregulate RFC1 we delivered lentiviral vector overexpressing RFC1. Retinal ischemia was induced 1-h by applying FeCl3 to central retinal artery. We used RT-qPCR and Western blotting to determine RFC1. Endothelium (CD31), pericytes (PDGFR-beta, CD13, NG2), tight-junctions (Occludin, Claudin-5 and ZO-1), main basal membrane protein (Collagen-4), endogenous IgG and RFC1 were determined immunohistochemically. RESULTS Our analyses on whole mount retinas and trypsin digested microvessel samples of adult mice revealed the presence of RFC1 in the inner BRB and colocalization with endothelial cells and pericytes. Knocking down RFC1 expression via siRNA delivery resulted in the disintegration of tight junction proteins and collagen-4 in twenty-four hours, which was accompanied by significant endogenous IgG extravasation. This indicated the impairment of BRB integrity after an abrupt RFC1 decrease. Furthermore, lentiviral vector-mediated RFC1 overexpression resulted in increased tight junction proteins and collagen-4, confirming the structural role of RFC1 in the inner BRB. Acute retinal ischemia decreased collagen-4 and occludin levels and led to an increase in RFC1. Besides, the pre-ischemic overexpression of RFC1 partially rescued collagen-4 and occludin levels which would be decreased after ischemia. CONCLUSION In conclusion, our study clarifies the presence of RFC1 protein in the inner BRB, which has recently been defined as hypoxia-immune-related gene in other tissues and offers a novel perspective of retinal RFC1. Hence, other than being a folate carrier, RFC1 is an acute regulator of the inner BRB in healthy and ischemic retinas.
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Affiliation(s)
- Gokce Gurler
- The Institute of Neurological Sciences and Psychiatry, Hacettepe University, Ankara, Turkey
| | - Nevin Belder
- Biotechnology Institute, Ankara University, Ankara, Turkey
| | | | | | - Gokhan Uruk
- The Institute of Neurological Sciences and Psychiatry, Hacettepe University, Ankara, Turkey
| | - Ertugrul Kilic
- Neuroscience and Neurotechnology Center of Excellence (NÖROM), Ankara, Turkey
- Physiology, Istanbul Medeniyet University, Istanbul, Turkey
| | - Muge Yemisci
- The Institute of Neurological Sciences and Psychiatry, Hacettepe University, Ankara, Turkey.
- Faculty of Medicine, Department of Neurology, Hacettepe University, Ankara, Turkey.
- Neuroscience and Neurotechnology Center of Excellence (NÖROM), Ankara, Turkey.
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Toll SJ, Qiu F, Huang Y, Habgood MD, Dziegielewska KM, Nie S, Saunders NR. Entry of antiepileptic drugs (valproate and lamotrigine) into the developing rat brain. F1000Res 2021; 10:384. [DOI: 10.12688/f1000research.52607.1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 04/26/2021] [Indexed: 01/13/2023] Open
Abstract
Background: Women with epilepsy face difficult choices whether to continue antiepileptic drug treatment during pregnancy, as uncontrolled seizures carry great risk to mother and fetus but continuing treatment may have adverse effects on baby’s development. This study aimed at evaluating antiepileptic drug entry into developing brain. Methods: Anaesthetised pregnant, non-pregnant adult females, postnatal and fetal rats were injected intraperitoneally with different doses, single or in combinations, of valproate and lamotrigine, all within clinical range. Injectate included 3H-labelled drug. After 30min, CSF, blood and brain samples were obtained; radioactivity was measured using liquid scintillation counting. Some animals were also exposed to valproate in feed throughout pregnancy and into neonatal period. Drug levels were measured by liquid chromatography coupled to mass spectrometry (LC-MS). Results are given as CSF or tissue/plasma% as index of drug entry. Results: Entry of valproate into brain and CSF was higher at E19 and P4 compared to adult but was not dose-dependent; placental transfer increased significantly at highest dose of 100mg/Kg. Lamotrigine entry into the brain was dose dependent only at E19. Chronic valproate treatment, or combination of valproate and lamotrigine had little effect on either drug entry, except for reduced valproate brain entry in adult brain with chronic treatment. Placental transfer decreased significantly after chronic valproate treatment. LC-MS measurement of valproate in adults confirmed that rat plasma values were within the clinical range and CSF/plasma and brain/plasma ratios for LC-MS and 3H-valproate were similar. Conclusion: Results suggest that entry of valproate may be higher in developing brain, the capacity of barrier mechanism is mostly unaffected by doses within the clinical range, with or without addition of lamotrigine. Chronic valproate exposure may result in upregulation in cellular mechanisms restricting its entry into the brain. Entry of lamotrigine was little different at different ages and was not dose dependent.
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Toll SJ, Qiu F, Huang Y, Habgood MD, Dziegielewska KM, Nie S, Saunders NR. Entry of antiepileptic drugs (valproate and lamotrigine) into the developing rat brain. F1000Res 2021; 10:384. [PMID: 34249340 PMCID: PMC8207807 DOI: 10.12688/f1000research.52607.2] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 07/19/2021] [Indexed: 12/13/2022] Open
Abstract
Background: Women with epilepsy face difficult choices whether to continue antiepileptic drug treatment during pregnancy, as uncontrolled seizures carry great risk to mother and fetus but continuing treatment may have adverse effects on baby’s development. This study aimed at evaluating antiepileptic drug entry into developing brain. Methods: Anaesthetised pregnant, non-pregnant adult females, postnatal and fetal rats were injected intraperitoneally with different doses, single or in combinations, of valproate and lamotrigine, within clinical range. Injectate included
3H-labelled drug. After 30min, CSF, blood and brain samples were obtained; radioactivity measured using liquid scintillation counting. Some animals were also exposed to valproate in feed throughout pregnancy and into neonatal period. Drug levels measured by liquid chromatography coupled to mass spectrometry (LC-MS). Results given as CSF or tissue/plasma% as index of drug entry. Results: Entry of valproate into brain and CSF was higher at E19 and P4 compared to adult and was dose-dependent except at E19; placental transfer increased significantly at highest dose of 100mg/kg. Lamotrigine entry into the brain was dose dependent only at E19. Chronic valproate treatment, or combination of valproate and lamotrigine had little effect on either drug entry, except for reduced valproate brain entry in adult brain with chronic treatment. Placental transfer decreased significantly after chronic valproate treatment. LC-MS measurement of valproate in adults confirmed that rat plasma values were within the clinical range and CSF/plasma and brain/plasma ratios for LC-MS and
3H-valproate were similar. Conclusion: Results suggest that entry of valproate may be higher in developing brain, the capacity of barrier mechanism is mostly unaffected by doses within the clinical range, with or without addition of lamotrigine. Chronic valproate exposure may result in upregulation in cellular mechanisms restricting its entry into the brain. Entry of lamotrigine was little different at different ages and was not dose dependent.
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Affiliation(s)
- Samuel J Toll
- Biochemistry & Pharmacology, University of Melbourne, Parkville, Victoria, 3010, Australia
| | - Fiona Qiu
- Biochemistry & Pharmacology, University of Melbourne, Parkville, Victoria, 3010, Australia
| | - Yifan Huang
- Biochemistry & Pharmacology, University of Melbourne, Parkville, Victoria, 3010, Australia
| | - Mark D Habgood
- Biochemistry & Pharmacology, University of Melbourne, Parkville, Victoria, 3010, Australia
| | | | - Shuai Nie
- Melbourne Mass Spectrometry and Proteomics Facility, Bio21 Institute, University of Melbourne, Parkville, Victoria, 3010, Australia
| | - Norman R Saunders
- Biochemistry & Pharmacology, University of Melbourne, Parkville, Victoria, 3010, Australia
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7
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Alam C, Kondo M, O'Connor DL, Bendayan R. Clinical Implications of Folate Transport in the Central Nervous System. Trends Pharmacol Sci 2020; 41:349-361. [PMID: 32200980 DOI: 10.1016/j.tips.2020.02.004] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2019] [Revised: 02/19/2020] [Accepted: 02/21/2020] [Indexed: 12/11/2022]
Abstract
Folates are essential for key biosynthetic processes in mammalian cells and play a crucial role in the maintenance of central nervous system homeostasis. Mammals lack the metabolic capacity for folate biosynthesis; hence, folate requirements are largely met through dietary sources. To date, three major folate transport pathways have been characterized: the folate receptors (FRs), reduced folate carrier (RFC), and proton-coupled folate transporter (PCFT). This article reviews current knowledge on the role of folate transport systems in mediating folate delivery to vital tissues, particularly the brain, and how these pathways are modulated by various regulatory mechanisms. We will also briefly highlight the clinical significance of cerebral folate transport in relation to neurodevelopmental disorders associated with folate deficiency.
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Affiliation(s)
- Camille Alam
- Department of Pharmaceutical Sciences, Leslie Dan Faculty of Pharmacy, University of Toronto, 144 College Street, Toronto, Ontario M5S 3M2, Canada
| | - Misaki Kondo
- Department of Pharmaceutical Sciences, Leslie Dan Faculty of Pharmacy, University of Toronto, 144 College Street, Toronto, Ontario M5S 3M2, Canada
| | - Deborah L O'Connor
- Translational Medicine Program, The Hospital for Sick Children, 686 Bay Street, Toronto, Ontario M5G 0A4, Canada; Department of Nutritional Sciences, University of Toronto, 1 King's College Circle, Toronto, Ontario M5S 1A8, Canada
| | - Reina Bendayan
- Department of Pharmaceutical Sciences, Leslie Dan Faculty of Pharmacy, University of Toronto, 144 College Street, Toronto, Ontario M5S 3M2, Canada.
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Gupta S, Kesarla R, Omri A. Approaches for CNS delivery of drugs - nose to brain targeting of antiretroviral agents as a potential attempt for complete elimination of major reservoir site of HIV to aid AIDS treatment. Expert Opin Drug Deliv 2020; 16:287-300. [PMID: 30779602 DOI: 10.1080/17425247.2019.1583206] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
INTRODUCTION Human immune-deficiency virus (HIV) infection causing acquired immune-deficiency syndrome (AIDS) is one of the most life-threatening infections. The central nervous system (CNS) is reported to be the most important HIV reservoir site where the antiretroviral drugs are unable to reach. AREAS COVERED This article includes the review about HIV infections, its pathogenesis, HIV infections in CNS, its consequences, current therapies, challenges associated with the existing therapies, approaches to overcome them, CNS delivery of drugs - barriers, transport routes, approaches for transporting drugs across the blood-brain barrier, nasal route of drug delivery, and nose to brain targeting of antiretroviral agents as a potential approach for complete cure of AIDS. EXPERT OPINION Various approaches are exploited to enhance the drug delivery to the brain for various categories of drugs. However, very few have investigated on the delivery of antiretrovirals to the brain. Targeting antiretrovirals to CNS through oral/nasal routes along with oral/parenteral delivery of drug to the plasma can be a promising approach for an attempt to completely eradicate HIV reservoir and cure AIDS, after clinical trials. Further research is required to identify the exact location of the HIV reservoir in CNS and developing good animal models for evaluation of different newly developed formulations.
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Affiliation(s)
- Shweta Gupta
- a Department of Pharmaceutics, Ideal College of Pharmacy and Research , University of Mumbai , Mumbai, Maharashtra , India
| | - Rajesh Kesarla
- b Corporate Quality Assurance , Zydus Cadila , Ahmedabad , Gujarat , India
| | - Abdelwahab Omri
- c The Novel Drug & Vaccine Delivery Systems Facility, Department of Chemistry and Biochemistry , Laurentian University , Sudbury , ON , Canada
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Engevik MA, Morra CN, Röth D, Engevik K, Spinler JK, Devaraj S, Crawford SE, Estes MK, Kalkum M, Versalovic J. Microbial Metabolic Capacity for Intestinal Folate Production and Modulation of Host Folate Receptors. Front Microbiol 2019; 10:2305. [PMID: 31649646 PMCID: PMC6795088 DOI: 10.3389/fmicb.2019.02305] [Citation(s) in RCA: 81] [Impact Index Per Article: 16.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2019] [Accepted: 09/20/2019] [Indexed: 12/19/2022] Open
Abstract
Microbial metabolites, including B complex vitamins contribute to diverse aspects of human health. Folate, or vitamin B9, refers to a broad category of biomolecules that include pterin, para-aminobenzoic acid (pABA), and glutamate subunits. Folates are required for DNA synthesis and epigenetic regulation. In addition to dietary nutrients, the gut microbiota has been recognized as a source of B complex vitamins, including folate. This study evaluated the predicted folate synthesis capabilities in the genomes of human commensal microbes identified in the Human Microbiome Project and folate production by representative strains of six human intestinal bacterial phyla. Bacterial folate synthesis genes were ubiquitous across 512 gastrointestinal reference genomes with 13% of the genomes containing all genes required for complete de novo folate synthesis. An additional 39% of the genomes had the genetic capacity to synthesize folates in the presence of pABA, an upstream intermediate that can be obtained through diet or from other intestinal microbes. Bacterial folate synthesis was assessed during exponential and stationary phase growth through the evaluation of expression of select folate synthesis genes, quantification of total folate production, and analysis of folate polyglutamylation. Increased expression of key folate synthesis genes was apparent in exponential phase, and increased folate polyglutamylation occurred during late stationary phase. Of the folate producers, we focused on the commensal Lactobacillus reuteri to examine host-microbe interactions in relation to folate and examined folate receptors in the physiologically relevant human enteroid model. RNAseq data revealed segment-specific folate receptor distribution. Treatment of human colonoid monolayers with conditioned media (CM) from wild-type L. reuteri did not influence the expression of key folate transporters proton-coupled folate transporter (PCFT) or reduced folate carrier (RFC). However, CM from L. reuteri containing a site-specific inactivation of the folC gene, which prevents the bacteria from synthesizing a polyglutamate tail on folate, significantly upregulated RFC expression. No effects were observed using L. reuteri with a site inactivation of folC2, which results in no folate production. This work sheds light on the contributions of microbial folate to overall folate status and mammalian host metabolism.
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Affiliation(s)
- Melinda A. Engevik
- Department of Pathology and Immunology, Baylor College of Medicine, Houston, TX, United States
- Department of Pathology, Texas Children’s Hospital, Houston, TX, United States
| | - Christina N. Morra
- Department of Pathology and Immunology, Baylor College of Medicine, Houston, TX, United States
- Integrative Molecular and Biomedical Sciences, Baylor College of Medicine, Houston, TX, United States
| | - Daniel Röth
- Department of Molecular Imaging and Therapy, Beckman Research Institute of the City of Hope, Duarte, CA, United States
| | - Kristen Engevik
- Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, TX, United States
| | - Jennifer K. Spinler
- Department of Pathology and Immunology, Baylor College of Medicine, Houston, TX, United States
- Department of Pathology, Texas Children’s Hospital, Houston, TX, United States
| | - Sridevi Devaraj
- Department of Pathology and Immunology, Baylor College of Medicine, Houston, TX, United States
- Department of Pathology, Texas Children’s Hospital, Houston, TX, United States
| | - Sue E. Crawford
- Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, TX, United States
| | - Mary K. Estes
- Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, TX, United States
- Department of Medicine – Gastroenterology, Hepatology and Infectious Diseases, Baylor College of Medicine, Houston, TX, United States
| | - Markus Kalkum
- Department of Molecular Imaging and Therapy, Beckman Research Institute of the City of Hope, Duarte, CA, United States
- Mass Spectrometry and Proteomics Core, Beckman Research Institute of the City of Hope, Duarte, CA, United States
| | - James Versalovic
- Department of Pathology and Immunology, Baylor College of Medicine, Houston, TX, United States
- Department of Pathology, Texas Children’s Hospital, Houston, TX, United States
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Tiani KA, Stover PJ, Field MS. The Role of Brain Barriers in Maintaining Brain Vitamin Levels. Annu Rev Nutr 2019; 39:147-173. [DOI: 10.1146/annurev-nutr-082018-124235] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
It is increasingly recognized that tissue-specific nutrient deficiencies can exist in the absence of whole-body deficiency and that these deficiencies may result from disease or disease-related physiological processes. Brain and central nervous system tissues require adequate nutrient levels to function. Many nutrients are concentrated in the cerebrospinal fluid relative to the serum in healthy individuals, and other nutrients resist depletion in the presence of whole-body nutrient depletion. The endothelial, epithelial, and arachnoid brain barriers work in concert to selectively transport, concentrate, and maintain levels of the specific nutrients required by the brain while also blocking the passage of blood-borne toxins and pathogens to brain and central nervous system tissues. These barriers preserve nutrient levels within the brain and actively concentrate nutrients within the cerebrospinal fluid and brain. The roles of physical and energetic barriers, including the blood–brain and blood–nerve barriers, in maintaining brain nutrient levels in health and disease are discussed.
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Affiliation(s)
- Kendra A. Tiani
- Division of Nutritional Sciences, Cornell University, Ithaca, New York 14853, USA
| | - Patrick J. Stover
- College of Agriculture and Life Sciences, Texas A & M University, College Station, Texas 77843-2142, USA
| | - Martha S. Field
- Division of Nutritional Sciences, Cornell University, Ithaca, New York 14853, USA
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Upregulation of reduced folate carrier by vitamin D enhances brain folate uptake in mice lacking folate receptor alpha. Proc Natl Acad Sci U S A 2019; 116:17531-17540. [PMID: 31405972 DOI: 10.1073/pnas.1907077116] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Folates are critical for central nervous system function. Folate transport is mediated by 3 major pathways, reduced folate carrier (RFC), proton-coupled folate transporter (PCFT), and folate receptor alpha (FRα/Folr1), known to be regulated by ligand-activated nuclear receptors. Cerebral folate delivery primarily occurs at the choroid plexus through FRα and PCFT; inactivation of these transport systems can result in very low folate levels in the cerebrospinal fluid causing childhood neurodegenerative disorders. These disorders have devastating effects in young children, and current therapeutic approaches are not sufficiently effective. Our group has previously reported in vitro that functional expression of RFC at the blood-brain barrier (BBB) and its upregulation by the vitamin D nuclear receptor (VDR) could provide an alternative route for brain folate uptake. In this study, we further demonstrated in vivo, using Folr1 knockout (KO) mice, that loss of FRα led to a substantial decrease of folate delivery to the brain and that pretreatment of Folr1 KO mice with the VDR activating ligand, calcitriol (1,25-dihydroxyvitamin D3), resulted in over a 6-fold increase in [13C5]-5-formyltetrahydrofolate ([13C5]-5-formylTHF) concentration in brain tissues, with levels comparable to wild-type animals. Brain-to-plasma concentration ratio of [13C5]-5-formylTHF was also significantly higher in calcitriol-treated Folr1 KO mice (15-fold), indicating a remarkable enhancement in brain folate delivery. These findings demonstrate that augmenting RFC functional expression at the BBB could effectively compensate for the loss of Folr1-mediated folate uptake at the choroid plexus, providing a therapeutic approach for neurometabolic disorders caused by defective brain folate transport.
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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.
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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
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13
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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.
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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.
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14
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Alam C, Hoque MT, Finnell RH, Goldman ID, Bendayan R. Regulation of Reduced Folate Carrier (RFC) by Vitamin D Receptor at the Blood-Brain Barrier. Mol Pharm 2017; 14:3848-3858. [PMID: 28885847 DOI: 10.1021/acs.molpharmaceut.7b00572] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Folates are essential for brain development and function. Folate transport in mammalian tissues is mediated by three major folate transport systems, i.e., reduced folate carrier (RFC), proton-coupled folate transporter (PCFT), and folate receptor alpha (FRα), known to be regulated by ligand-activated nuclear receptors, such as vitamin D receptor (VDR). Folate uptake at the choroid plexus, which requires the actions of both FRα and PCFT, is critical to cerebral folate delivery. Inactivating FRα or PCFT mutations cause severe cerebral folate deficiency resulting in early childhood neurodegeneration. The objective of this study was to investigate the role of RFC in folate uptake at the level of the blood-brain barrier (BBB) and its potential regulation by VDR. We detected robust expression of RFC in different in vitro BBB model systems, particularly in immortalized cultures of human cerebral microvascular endothelial cells (hCMEC/D3) and isolated mouse brain capillaries. [3H]-methotrexate uptake by hCMEC/D3 cells at pH 7.4 was inhibited by PT523 and pemetrexed, antifolates with high affinity for RFC. We also showed that activation of VDR through calcitriol (1,25-dihydroxyvitamin D3) exposure up-regulates RFC mRNA and protein expression as well as function in hCMEC/D3 cells and isolated mouse brain capillaries. We further demonstrated that RFC expression could be down-regulated by VDR-targeting siRNA, further confirming the role of VDR in the direct regulation of this folate transporter. Together, these data suggest that augmenting RFC functional expression could constitute a novel strategy for enhancing brain folate delivery for the treatment of neurometabolic disorders caused by loss of FRα or PCFT function.
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Affiliation(s)
- Camille Alam
- Department of Pharmaceutical Sciences, Leslie Dan Faculty of Pharmacy, University of Toronto , Toronto, Ontario M5S 3M2, Canada
| | - Md Tozammel Hoque
- Department of Pharmaceutical Sciences, Leslie Dan Faculty of Pharmacy, University of Toronto , Toronto, Ontario M5S 3M2, Canada
| | - Richard H Finnell
- Departments of Molecular and Cellular Biology and Medicine, Baylor College of Medicine , Houston, Texas 77030, United States
| | - I David Goldman
- Department of Molecular Pharmacology, Albert Einstein College of Medicine , Bronx, New York 10461, United States
| | - Reina Bendayan
- Department of Pharmaceutical Sciences, Leslie Dan Faculty of Pharmacy, University of Toronto , Toronto, Ontario M5S 3M2, Canada
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Han H, Mann A, Ekstein D, Eyal S. Breaking Bad: the Structure and Function of the Blood-Brain Barrier in Epilepsy. AAPS JOURNAL 2017; 19:973-988. [DOI: 10.1208/s12248-017-0096-2] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/15/2017] [Accepted: 04/28/2017] [Indexed: 12/27/2022]
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16
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Yang Y, Wu N, Wang Z, Zhang F, Tian R, Ji W, Ren X, Niu R. Rack1 Mediates the Interaction of P-Glycoprotein with Anxa2 and Regulates Migration and Invasion of Multidrug-Resistant Breast Cancer Cells. Int J Mol Sci 2016; 17:ijms17101718. [PMID: 27754360 PMCID: PMC5085749 DOI: 10.3390/ijms17101718] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2016] [Revised: 09/18/2016] [Accepted: 10/07/2016] [Indexed: 12/11/2022] Open
Abstract
The emergence of multidrug resistance is always associated with more rapid tumor recurrence and metastasis. P-glycoprotein (P-gp), which is a well-known multidrug-efflux transporter, confers enhanced invasion ability in drug-resistant cells. Previous studies have shown that P-gp probably exerts its tumor-promoting function via protein-protein interaction. These interactions were implicated in the activation of intracellular signal transduction. We previously showed that P-gp binds to Anxa2 and promotes the invasiveness of multidrug-resistant (MDR) breast cancer cells through regulation of Anxa2 phosphorylation. However, the accurate mechanism remains unclear. In the present study, a co-immunoprecipitation coupled with liquid chromatography tandem mass spectrometry-based interactomic approach was performed to screen P-gp binding proteins. We identified Rack1 as a novel P-gp binding protein. Knockdown of Rack1 significantly inhibited proliferation and invasion of MDR cancer cells. Mechanistic studies demonstrated that Rack1 functioned as a scaffold protein that mediated the binding of P-gp to Anxa2 and Src. We showed that Rack1 regulated P-gp activity, which was necessary for adriamycin-induced P-gp-mediated phosphorylation of Anxa2 and Erk1/2. Overall, the findings in this study augment novel insights to the understanding of the mechanism employed by P-gp for promoting migration and invasion of MDR cancer cells.
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Affiliation(s)
- Yi Yang
- Public Laboratory, Tianjin Medical University Cancer Institute and Hospital, National Clinical Research Center for Cancer, Tianjin 300060, China.
- Key Laboratory of Cancer Prevention and Therapy, Tianjin Medical University Cancer Institute and Hospital, Tianjin 300060, China.
- Tianjin's Clinical Research Center for Cancer, Tianjin Medical University Cancer Institute and Hospital, Tianjin 300060, China.
- Key Laboratory of Breast Cancer Prevention and Therapy, Tianjin Medical University, Ministry of Education, Tianjin 300060, China.
| | - Na Wu
- Key Laboratory of Cancer Prevention and Therapy, Tianjin Medical University Cancer Institute and Hospital, Tianjin 300060, China.
- Tianjin's Clinical Research Center for Cancer, Tianjin Medical University Cancer Institute and Hospital, Tianjin 300060, China.
- Department of Immunology, Tianjin Medical University Cancer Institute and Hospital, National Clinical Research Center for Cancer, Tianjin 300060, China.
- Key Laboratory of Cancer Immunology and Biotherapy, Tianjin Medical University Cancer Institute and Hospital, Tianjin 300060, China.
| | - Zhiyong Wang
- Public Laboratory, Tianjin Medical University Cancer Institute and Hospital, National Clinical Research Center for Cancer, Tianjin 300060, China.
- Key Laboratory of Cancer Prevention and Therapy, Tianjin Medical University Cancer Institute and Hospital, Tianjin 300060, China.
- Tianjin's Clinical Research Center for Cancer, Tianjin Medical University Cancer Institute and Hospital, Tianjin 300060, China.
- Key Laboratory of Breast Cancer Prevention and Therapy, Tianjin Medical University, Ministry of Education, Tianjin 300060, China.
| | - Fei Zhang
- Public Laboratory, Tianjin Medical University Cancer Institute and Hospital, National Clinical Research Center for Cancer, Tianjin 300060, China.
- Key Laboratory of Cancer Prevention and Therapy, Tianjin Medical University Cancer Institute and Hospital, Tianjin 300060, China.
- Tianjin's Clinical Research Center for Cancer, Tianjin Medical University Cancer Institute and Hospital, Tianjin 300060, China.
- Key Laboratory of Breast Cancer Prevention and Therapy, Tianjin Medical University, Ministry of Education, Tianjin 300060, China.
| | - Ran Tian
- Public Laboratory, Tianjin Medical University Cancer Institute and Hospital, National Clinical Research Center for Cancer, Tianjin 300060, China.
- Key Laboratory of Cancer Prevention and Therapy, Tianjin Medical University Cancer Institute and Hospital, Tianjin 300060, China.
- Tianjin's Clinical Research Center for Cancer, Tianjin Medical University Cancer Institute and Hospital, Tianjin 300060, China.
- Key Laboratory of Breast Cancer Prevention and Therapy, Tianjin Medical University, Ministry of Education, Tianjin 300060, China.
| | - Wei Ji
- Public Laboratory, Tianjin Medical University Cancer Institute and Hospital, National Clinical Research Center for Cancer, Tianjin 300060, China.
- Key Laboratory of Cancer Prevention and Therapy, Tianjin Medical University Cancer Institute and Hospital, Tianjin 300060, China.
- Tianjin's Clinical Research Center for Cancer, Tianjin Medical University Cancer Institute and Hospital, Tianjin 300060, China.
- Key Laboratory of Breast Cancer Prevention and Therapy, Tianjin Medical University, Ministry of Education, Tianjin 300060, China.
| | - Xiubao Ren
- Key Laboratory of Cancer Prevention and Therapy, Tianjin Medical University Cancer Institute and Hospital, Tianjin 300060, China.
- Tianjin's Clinical Research Center for Cancer, Tianjin Medical University Cancer Institute and Hospital, Tianjin 300060, China.
- Department of Immunology, Tianjin Medical University Cancer Institute and Hospital, National Clinical Research Center for Cancer, Tianjin 300060, China.
- Key Laboratory of Cancer Immunology and Biotherapy, Tianjin Medical University Cancer Institute and Hospital, Tianjin 300060, China.
| | - Ruifang Niu
- Public Laboratory, Tianjin Medical University Cancer Institute and Hospital, National Clinical Research Center for Cancer, Tianjin 300060, China.
- Key Laboratory of Cancer Prevention and Therapy, Tianjin Medical University Cancer Institute and Hospital, Tianjin 300060, China.
- Tianjin's Clinical Research Center for Cancer, Tianjin Medical University Cancer Institute and Hospital, Tianjin 300060, China.
- Key Laboratory of Breast Cancer Prevention and Therapy, Tianjin Medical University, Ministry of Education, Tianjin 300060, China.
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Peng L, Dreumont N, Coelho D, Guéant JL, Arnold C. Genetic animal models to decipher the pathogenic effects of vitamin B12 and folate deficiency. Biochimie 2016; 126:43-51. [DOI: 10.1016/j.biochi.2016.05.007] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2016] [Accepted: 05/06/2016] [Indexed: 01/20/2023]
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18
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The effects of 2,3,7,8-tetrachlorodibenzo-p-dioxin on the development and function of the blood–brain barrier. Neurotoxicology 2016; 52:64-71. [DOI: 10.1016/j.neuro.2015.11.003] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2015] [Revised: 11/05/2015] [Accepted: 11/09/2015] [Indexed: 01/03/2023]
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Krishnamurthy S, Tichenor MD, Satish AG, Lehmann DB. A proposed role for efflux transporters in the pathogenesis of hydrocephalus. Croat Med J 2015; 55:366-76. [PMID: 25165050 PMCID: PMC4157374 DOI: 10.3325/cmj.2014.55.366] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
Hydrocephalus is a common brain disorder that is treated only with surgery. The basis for surgical treatment rests on the circulation theory. However, clinical and experimental data to substantiate circulation theory have remained inconclusive. In brain tissue and in the ventricles, we see that osmotic gradients drive water diffusion in water-permeable tissue. As the osmolarity of ventricular CSF increases within the cerebral ventricles, water movement into the ventricles increases and causes hydrocephalus. Macromolecular clearance from the ventricles is a mechanism to establish the normal CSF osmolarity, and therefore ventricular volume. Efflux transporters, (p-glycoprotein), are located along the blood brain barrier and play an important role in the clearance of macromolecules (endobiotics and xenobiotics) from the brain to the blood. There is clinical and experimental data to show that macromolecules are cleared out of the brain in normal and hydrocephalic brains. This article summarizes the existing evidence to support the role of efflux transporters in the pathogenesis of hydrocephalus. The location of p-gp along the pathways of macromolecular clearance and the broad substrate specificity of this abundant transporter to a variety of different macromolecules are reviewed. Involvement of p-gp in the transport of amyloid beta in Alzheimer disease and its relation to normal pressure hydrocephalus is reviewed. Finally, individual variability of p-gp expression might explain the variability in the development of hydrocephalus following intraventricular hemorrhage.
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Hegedüs C, Hegedüs T, Sarkadi B. The Role of ABC Multidrug Transporters in Resistance to Targeted Anticancer Kinase Inhibitors. RESISTANCE TO TARGETED ANTI-CANCER THERAPEUTICS 2015. [DOI: 10.1007/978-3-319-09801-2_9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
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Campos-Bedolla P, Walter FR, Veszelka S, Deli MA. Role of the Blood–Brain Barrier in the Nutrition of the Central Nervous System. Arch Med Res 2014; 45:610-38. [DOI: 10.1016/j.arcmed.2014.11.018] [Citation(s) in RCA: 114] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2014] [Accepted: 11/24/2014] [Indexed: 12/22/2022]
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Abstract
The properties of intestinal folate absorption were documented decades ago. However, it was only recently that the proton-coupled folate transporter (PCFT) was identified and its critical role in folate transport across the apical brush-border membrane of the proximal small intestine established by the loss-of-function mutations identified in the PCFT gene in subjects with hereditary folate malabsorption and, more recently, by the Pcft-null mouse. This article reviews the current understanding of the properties of PCFT-mediated transport and how they differ from those of the reduced folate carrier. Other processes that contribute to the transport of folates across the enterocyte, along with the contribution of the enterohepatic circulation, are considered. Important unresolved issues are addressed, including the mechanism of intestinal folate absorption in the absence of PCFT and regulation of PCFT gene expression. The impact of a variety of ions, organic molecules, and drugs on PCFT-mediated folate transport is described.
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Affiliation(s)
- Michele Visentin
- Departments of Molecular Pharmacology and Medicine, Albert Einstein College of Medicine, Bronx, New York 10461; , , ,
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Nrf2 upregulates ATP binding cassette transporter expression and activity at the blood-brain and blood-spinal cord barriers. J Neurosci 2014; 34:8585-93. [PMID: 24948812 DOI: 10.1523/jneurosci.2935-13.2014] [Citation(s) in RCA: 126] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Activation of nuclear factor E2-related factor-2 (Nrf2), a sensor of oxidative stress, is neuroprotective in animal models of cerebral ischemia, traumatic brain injury, subarachnoid hemorrhage, and spinal cord injury. We show here that Nrf2 activation with sulforaphane (SFN) in vivo or in vitro increases expression and transport activity of three ATP-driven drug efflux pumps at the blood-brain barrier [P-glycoprotein, ATP binding cassette b1 (Abcb1); multidrug resistance-associated protein-2 (Mrp2), Abcc2; and breast cancer resistance protein (Bcrp), Abcg2]. Dosing rats with SFN increased protein expression of all three transporters in brain capillaries and decreased by 50% brain accumulation of the P-glycoprotein substrate verapamil. Exposing rat or mouse brain capillaries to SFN increased P-glycoprotein, Bcrp, and Mrp2 transport activity and protein expression; SFN increased P-glycoprotein activity in mouse spinal cord capillaries. Inhibiting transcription or translation abolished upregulation of P-glycoprotein activity. No such effects were seen in brain capillaries from Nrf2-null mice, indicating Nrf2 dependence. Nrf2 signaled indirectly to increase transporter activity/expression. The p53 inhibitor pifithrin abolished the SFN-induced increase in transporter activity/expression, and the p53-activator nutlin-3 increased P-glycoprotein activity. SFN did not alter P-glycoprotein transport activity in brain and spinal cord capillaries from p53-null mice. Inhibitors of p38 MAPK and nuclear factor κB (NF-κB) blocked the effects of SFN and nutlin-3 on P-glycoprotein activity. These results implicate Nrf2, p53, and NF-κB in the upregulation of P-glycoprotein, Bcrp, and Mrp2 at blood-CNS barriers. They imply that the barriers are tightened selectively (efflux transporter upregulation) by oxidative stress, providing increased neuroprotection, but also reduced penetration of many therapeutic drugs.
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Tachikawa M, Uchida Y, Ohtsuki S, Terasaki T. Recent Progress in Blood–Brain Barrier and Blood–CSF Barrier Transport Research: Pharmaceutical Relevance for Drug Delivery to the Brain. DRUG DELIVERY TO THE BRAIN 2014. [DOI: 10.1007/978-1-4614-9105-7_2] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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Role of nuclear receptors in the regulation of drug transporters in the brain. Trends Pharmacol Sci 2013; 34:361-72. [PMID: 23769624 DOI: 10.1016/j.tips.2013.05.004] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2013] [Revised: 04/24/2013] [Accepted: 05/08/2013] [Indexed: 02/07/2023]
Abstract
ATP-binding cassette membrane-associated drug efflux transporters and solute carrier influx transporters, expressed at the blood-brain barrier, blood-cerebrospinal fluid barrier, and in brain parenchyma, are important determinants of drug disposition in the central nervous system. Targeting the regulatory pathways that govern the expression of these transporters could provide novel approaches to selectively alter drug permeability into the brain. Nuclear receptors are ligand-activated transcription factors which regulate the gene expression of several metabolic enzymes and drug efflux/influx transporters. Although efforts have primarily been focused on investigating these regulatory pathways in peripheral organs (i.e., liver and intestine), recent findings demonstrate their significance in the brain. This review addresses the role of nuclear receptors in the regulation of drug transporter functional expression in the brain. An in-depth understanding of these pathways could guide the development of novel pharmacotherapy with either enhanced efficacy in the central nervous system or minimal associated neurotoxicity.
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