Brain endothelial cell

Biemacki K, Prat A, Blain M, Antel JP (2001) Regulation of Thl and Th2 lymphocyte migration by human adult brain endothelial cells. J Neuropathol Exp Neurol 60 1127-1136 Bleul CC, Farzan M, Choe H, Parolin C, Clark-Lewis I, Sodroski J, Springer TA (1996a) The lymphocyte chemoattractant SDF-1 is a ligand for LESTR/fusin and blocks HIV-1 entry. Nature 382 829-833... 

Kerper LE University of Rochester, Rochester, NY Intracellular lead-calcium interactions (bovine brain endothelial cells) National Institute of Environmental Health Sciences... 

Proulx [30] summarized the published lipid compositions of BBM isolated from epithelial cells from pig, rabbit, mouse and rat small intestines. Table 3.1 shows the lipid make-up for the rat, averaged from five reported studies [30], On a molar basis, cholesterol accounts for about 50% of the total lipid content (37% on a weight basis). Thus, the cholesterol content in BBM is higher than that found in kidney epithelial (MDCK) and brain endothelial cells (Table 3.1). Slightly different BBM lipid distribution was reported by Alcorn et al. [31] here, the outer (luminal) leaflet of the BBM was seen to be rich in sphingomyelin content, while the inner leaflet (cytosol) was rich in PE and PC. Apical (brush border) and basolateral lipids are different in epithelia. The basolateral membrane content (not reported by... 

The presence at the BBB of members of the multidrug resistance-associated protein (MRPs) family, whose members preferentially transport anionic compounds, is still controversial. The seven members of the MRP family belong, like P-gp, to the ATP-binding cassette (ABC) protein superfamily. Mrpl has been found at the BBB in isolated rat brain capillaries, primary cultures of brain capillary endothelial cells and in immortalized capillary endothelial cells, but not in human brain capillaries [59]. Another member, MRP2 has been found at the luminal membrane of the brain endothelial cells [60]. However, further studies are required to show that there are MRP transporters at the BBB (Figure 15.5). As for P-gp, a functional Mrpl was found in primary cultured rat astrocytes [56] and it has been shown to take part in the release of glutathione disulfide from brain astrocytes under oxidative stress [61]. 

Adipocytes have an important secretory function. Numerous factors (collectively termed adipokines or adipocytokines), mostly peptides but also eicosanoids are produced by preadipocytes and mature adipocytes (Table 9.3). Some of these factors act in an autocrine or paracrine fashion to regulate adipogenesis, that is differentiation and maturation of adipocytes themselves, whilst others, notably, leptin, adiponectin and some cytokines act in truly endocrine way, having effects on the brain, endothelial cells, liver and skeletal muscle. Disturbance in secretion from adipocytes is associated with eating disorders and metabolic syndrome. 

Freshly isolated or subcultured brain microvascular endothelial cells offer a notable in vitro tool to study drug transport across the blood-brain barrier. Cells can be grown to monolayers on culture plates or permeable membrane supports. The cells retain the major characteristics of brain endothelial cells in vivo, such as the morphology, specific biochemical markers of the blood-brain barrier, and the intercellular tight junctional network. Examples of these markers are y-glutamyl transpeptidase, alkaline phosphatase, von-Willebrandt factor-related antigen, and ZO-1 tight junctional protein. The methods of... 

A cell line is a continuously growing cell population, which is derived from tumor cells or from primary cells, which have been immortalized using appropriate vectors. There are several lines of blood-brain barrier endothelial cells available, for example, MBECs (mouse brain endothelial cells), RBE4 cells (rat brain endothelial cells, clone 4), PBMECs (porcine brain microvessel... 

Demeuse P, Fragner P, Leroy-Noury C, Mercier C, Payen L, Fardel O, Couraud PO, Roux F (2004) Puromycin selectively increases mdrl a expression in immortalized rat brain endothelial cell lines. J Neurochem 88 23-31... 

The transport of amino acids at the BBB differs depending on their chemical class and the dual function of some amino acids as nutrients and neurotransmitters. Essential large neutral amino acids are shuttled into the brain by facilitated transport via the large neutral amino acid transporter (LAT) system [29] and display rapid equilibration between plasma and brain concentrations on a minute time scale. The LAT-system at the BBB shows a much lower Km for its substrates compared to the analogous L-system of peripheral tissues and its mRNA is highly expressed in brain endothelial cells (100-fold abundance compared to other tissues). Cationic amino acids are taken up into the brain by a different facilitative transporter, designated as the y system, which is present on the luminal and abluminal endothelial membrane. In contrast, active Na -dependent transporters for small neutral amino acids (A-system ASC-system) and cationic amino acids (B° system), appear to be confined to the abluminal surface and may be involved in removal of amino acids from brain extracellular fluid [30]. Carrier-mediated BBB transport includes monocarboxylic acids (pyruvate), amines (choline), nucleosides (adenosine), purine bases (adenine), panthotenate, thiamine, and thyroid hormones (T3), with a representative substrate given in parentheses [31]. 

Hipkiss, A. R., Preston, J. E., Himsworth, D. T., Worthington, V. C., and Abbott, N. J. (1997). Protective effects of carnosine against malondialdehyde-induced toxicity towards cultured rat brain endothelial cells. Neurosci. Lett. 238,135-138. 

Primary cultures developed from pig and cow tissue are the best studied [29-32]. These models closely resemble the BBB, exhibiting many of the key biological properties. However isolation of blood-brain endothelial cells requires relatively complex cell isolation procedures which are labor-intensive and not ideal for screening purposes. Other cell types have been shown or proposed to induce barrier function, for example, astrocytes/pericytes. Significant improvements in barrier function was achieved in these primary culture models by including astrocyte conditioned media or co-culturing with astrocytes [33]. The complexity of primary cultures led to the use of epithelial cell lines not derived from the BBB (e.g., MDCK, MDCK-MDRl or LLC-PKl) [33]. 

Garberg et al. compared a number of in vitro cell models of the BBB with in vivo data (including primary cow and human brain endothelial cells co-cultured with astrocytes, MDCK, MDCK-MDRl, Caco-2, ECV304/C6, MBEC4, SV-ARBEC cocultured with astrocytes). The best correlation, although poor, was seen with cow brain endothelial cells (r 0.43) and MDCK (r 0.46). The correlation was improved with Caco-2 when only passively transported compounds were included in the analysis (r = 0.86), BBEC showing a similar correlation [39]. 

Kannan R, Mittur A, Bao Y, Tsuruo T, Kaplowitz N. 1999. GSH transport in immortalized mouse brain endothelial cells Evidence for apical localization of a sodium-dependent GSH transporter. J Neurochem 73 390-399. 

Neuhaus, J., W. Risau, and H. Wolburg. 1991. Induction of blood-brain barrier characteristics in bovine brain endothelial cells by rat astroglial cells in transfilter coculture. Ann N Y Acad Sci 633 578. 

NE also influences the expression of other genes involved in the inflammatory response in the brain, such as MHC class II antigen and ICAM-1. More specifically, NE has opposite effects on these gene products depending on the cell type, like reducing the expression of MHC class II in glial cells, while enhancing MHC class II in IFNy-stimulated bovine brain endothelial cells. On the other hand, NE reduces the expression of ICAM in both astrocytes and brain endothelial cells (Feinstein et al., 2002). 

In addition to the permeability barrier of the capillary endothelium, highly active enzymes present in the brain endothelial cells, pericytes and astrocytes, represent a further metabolic component of the BBB that also restricts the entry of substances to the brain. This is further compounded by the presence of the p-glycoprotein active efflux system in the astrocyte membranes (see below) these various components work in parallel with the permeability barrier of the capillary endothelium, to form a multicomponent BBB. 

Prof. H-J Galla (University of Muenster, Germany) has already established an in vitro BBB model with murine brain capillary endothelial cells based on this procedure (not yet published). Thus, this procedure might easily be adapted to brain endothelial cells of other relevant species in drag discovery like rat, dog, rabbit. 

Begley DJ, Lechardeur D, Chen ZD et al. (1996) Functional expression of P-glycoprotein in an immortalised cell line of rat brain endothelial cells, RBE4. J Neurochem 67 988-995... 

Bowman PD, Betz AL, Goldstein GW (1982) Primary culture of microvascular endothelial cells from bovine retina selective growth using fibronectin coated substrate and plasma derived serum. In Vitro 18 626-632 Chat M, Bayol-Denizot C, Suleman G et al. (1998) Drug metabolizing enzyme activities and superoxide formation in primary and immortalized rat brain endothelial cells. Life Sci 62 151-163... 

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