Characterization of uptake of folates by rat and human blood-brain barrier endothelial cells

Department of Biochemistry (U38-FCT), Faculty of Medicine, University of Porto, Porto, Portugal.
BioFactors (Impact Factor: 4.59). 05/2010; 36(3):201-9. DOI: 10.1002/biof.82
Source: PubMed

ABSTRACT This study aimed to characterize (3)H-folic acid ((3)H-FA) and (14)C-methyltetrahydrofolic acid ((14)C-MTHF) uptake by rat (RBE4) and human (hCMEC/D3) blood-brain barrier (BBB) endothelial cell lines. Uptake of (3)H-FA and (14)C-MTHF by RBE4 cells was time dependent and linear for the first 2 min of incubation; uptake by hCMEC/D3 cells showed a less marked time-dependency and a greater experimental variability. So, further experiments were performed in RBE4 cells only. Uptake of (3)H-FA was stimulated at acidic and alkaline pH, Na(+) dependent, stimulated when F(-) substituted for Cl(-), energy independent, inhibited by premetrexed, stimulated by cytochalasin D, and unaffected by MTHF, DIDS, SITS, methotrexate, monensin, and FA. Uptake of (14)C-MTHF was found to be pH-, Na(+)-, Cl(-)- and energy independent, inhibited by premetrexed and methotrexate, stimulated by cytochalasin D, and unaffected by FA, DIDS, SITS, monensin, and MTHF. RT-PCR analysis showed mRNA expression of reduced folate transporter (RFC), but neither of FRalpha nor of proton-coupled folate transporter (PCFT) in RBE4 cells, and mRNA expression of RFC and PCFT, but not of FRalpha, in hCMEC/D3 cells. In conclusion, both human and rat BBB endothelial cells show little capacity for (3)H-FA and (14)C-MTHF apical uptake. Hence, these cell lines do not appear to be a good model to study the transport of folates at the BBB.

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Available from: Pedro Gonçalves, Sep 29, 2015
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    • "Several substances, e.g., dietary components, hormones, therapeutic drugs and drugs of abuse, have been shown to influence different transporters at different levels (e.g., enterocyte, colon, placenta) (Araujo et al. 2010; Goncalves et al. 2009, 2011; Keating et al. 2007, 2009; Martel et al. 2010). Particularly, glucose transport was shown to be modified by flavonoids, vitamins and drugs of abuse (Araujo et al. 2008; Faria et al. 2009; Keating et al. 2009; Martel et al. 2010). "
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    ABSTRACT: The blood-brain barrier (BBB) plays a key role in limiting and regulating glucose access to glial and neuronal cells. In this work glucose uptake on a human BBB cell model (the hCMEC/D3 cell line) was characterized. The influence of some hormones and diet components on glucose uptake was also studied. (3)H-2-deoxy-D-glucose ([(3)H]-DG) uptake for hCMEC/D3 cells was evaluated in the presence or absence of tested compounds. [(3)H]-DG uptake was sodium- and energy-independent. [(3)H]-DG uptake was regulated by Ca(2+) and calmodulin but not by MAPK kinase pathways. PKC, PKA and protein tyrosine kinase also seem to be involved in glucose uptake modulation. Progesterone and estrone were found to decrease (3)H-DG uptake. Catechin and epicatechin did not have any effect, but their methylated metabolites increased [(3)H]-DG uptake. Quercetin and myricetin decreased [(3)H]-DG uptake, and glucuronic acid-conjugated quercetin did not have any effect. These cells expressed GLUT1, GLUT3 and SGLT1 mRNA.
    Journal of Membrane Biology 08/2013; 246(9). DOI:10.1007/s00232-013-9583-2 · 2.46 Impact Factor
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    ABSTRACT: The blood-brain barrier (BBB) is a dynamic and complex interface between the blood and the central nervous system regulating brain homeostasis. Major functions of the BBB include the transport of nutrients and protection of the brain from toxic compounds. This review summarizes the most important transport pathways contributing to the nutrition of the brain. Carrier-mediated transport selectively delivers small molecules like sugars, amino acids, vitamins, and trace elements. Large biomolecules, lipoproteins, peptide and protein hormones cross the BBB by receptor-mediated transport. Active efflux transporters participate in the brain efflux of endogenous metabolites as well as toxins, xenobiotics and drugs. Dysfunction in the transport of nutrients at the BBB is described in several neurological disorders and diseases. The BBB penetration of neuroprotective nutrients, especially plant polyphenols and alkaloids, their potential protective effect on brain endothelium and the interaction of nutraceuticals with active efflux transporters at the BBB are discussed. In vitro BBB models to examine nutrient transport are also presented. Copyright © 2014 IMSS. Published by Elsevier Inc. All rights reserved.
    Archives of Medical Research 12/2014; 45(8). DOI:10.1016/j.arcmed.2014.11.018 · 2.65 Impact Factor