Inter-Communication Between Brain Capillary Endothelial Cells and Astrocytes: Upregulation of the LDL Receptor at the Blood-Brained Barrier

Abstract

The presence of lipoproteins, a olipoproteins and their receptors in the brain could provide a system for cholesterol homeostasis, as they do in other tissues. Our previous work demonstrating in vivo the occurrence of a low density lipoprotein (LDL) receptor on the BBB has suggested that this cerebralendothelial receptor plays a role in lipid transport across the BBB (Meresse, S. et al., 1989). To examine further the function of this receptor, we have established an in vivo model, that closely mimics the in vivo situation, by co-culturing brain capillary endothelial cells on one side of a filter and astrocytes on the other (Dehouck, M.P. et al, 1990). When cultured separately, the brain capillary endothelial cells express a LDL receptor with the same apparent molecular weight as in vivo. When the astrocytes and the brain capillary endothelial were co-cultured, the number of LDL receptors located at the lummal side increased by ~3 fold.