Scavenger receptor class B, type I is expressed in porcine brain capillary endothelial cells and contributes to selective uptake of HDL-associated vitamin E
| Autor: | Daniel Goti, Deneys R. van der Westhuyzen, Andelko Hrzenjak, Wolfgang Sattler, Sanja Levak-Frank, Saša Frank, Ernst Malle |
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| Rok vydání: | 2001 |
| Předmět: |
CD36 Antigens
medicine.medical_specialty Swine media_common.quotation_subject CHO Cells Biology Transfection Blood–brain barrier Biochemistry Lipoprotein particle Cellular and Molecular Neuroscience Cricetinae Internal medicine medicine Animals Vitamin E Receptors Immunologic Scavenger receptor Internalization Cells Cultured Receptors Lipoprotein media_common Receptors Scavenger Chinese hamster ovary cell Brain Membrane Proteins Lipoproteins HDL3 Scavenger Receptors Class B Capillaries Cell biology Endothelial stem cell Endocrinology medicine.anatomical_structure Blood-Brain Barrier lipids (amino acids peptides and proteins) Endothelium Vascular Lipoproteins HDL Lipoprotein |
| Zdroj: | Journal of Neurochemistry. 76:498-508 |
| ISSN: | 1471-4159 0022-3042 |
| Popis: | It is clearly established that an efficient supply to the brain of alpha-tocopherol (alphaTocH), the most biologically active member of the vitamin E family, is of the utmost importance for proper neurological functioning. Although the mechanism of uptake of alphaTocH into cells constituting the blood-brain barrier (BBB) is obscure, we previously demonstrated that high-density lipoprotein (HDL) plays a major role in the supply of alphaTocH to porcine brain capillary endothelial cells (pBCECs). Here we studied whether a porcine analogue of human and rodent scavenger receptor class B, type I mediates selective (without concomitant lipoprotein particle internalization) uptake of HDL-associated alphaTocH in a similar manner to that described for HDL-associated cholesteryl esters (CEs). In agreement with this hypothesis we observed that a major proportion of alphaTocH uptake by pBCECs occurred by selective uptake, exceeding HDL3 holoparticle uptake by up to 13-fold. The observation that selective uptake of HDL-associated CE exceeded HDL3 holoparticle up to fourfold suggested that a porcine analogue of SR-BI (pSR-BI) may be involved in lipid uptake at the BBB. In line with the observation of selective lipid uptake, RT-PCR and northern and western blot analyses revealed the presence of pSR-BI in cells constituting the BBB. Adenovirus-mediated overexpression of the human analogue of SR-BI (hSR-BI) in pBCECs resulted in a fourfold increase in selective HDL-associated alphaTocH uptake. In accordance with the proposed function of SR-BI, selective HDL-CE uptake was increased sixfold in Chinese hamster ovary cells stably transfected with murine SR-BI (mSR-BI). Most importantly stable mSR-BI overexpression mediated a twofold increase in HDL-associated [14C]alphaTocH selective uptake in comparison with control cells. In line with tracer experiments, mass transfer studies with unlabelled lipoproteins revealed that mSR-BI overexpression resulted in a twofold increase in endogenous HDL3-associated alphaTocH uptake. The results of this study indicate that SR-BI promotes the uptake of HDL-associated alphaTocH into cells constituting the BBB and plays an important role during the supply of the CNS with this indispensable micronutrient. |
| Databáze: | OpenAIRE |
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