The blood-brain barrier (BBB) is the main interface controlling molecular and cellular traffic between the central nervous system (CNS) and the periphery. It consists of cerebral endothelial cells (CECs) interconnected by continuous tight junctions, and closely associated pericytes and astrocytes. Different parts of the CNS have diverse functions and structure and may be subjects of different pathologies, in which the BBB is actively involved. It is largely unknown however, what are the cellular and molecular differences of the BBB in different regions of the brain. Using in silico, in vitro and ex vivo techniques we compared the expression of BBB-associated genes and proteins (i.e. markers of CECs, brain pericytes and astrocytes) in the cortical grey matter and white matter. In silico human database analysis (obtained from recalculated data of the Allen Brain Atlas), qPCR, western-blot and immunofluorescence studies on porcine and mouse brain tissue indicated an increased expression of GFAP in astrocytes in the white matter in comparison to the grey matter. We have also found increased expression of genes of the junctional complex of CECs (occludin, claudin-5, α-catenin) in the white matter in comparison to the cerebral cortex. Accordingly, occludin, claudin-5 and α-catenin proteins showed increased expression in CECs of the white matter in comparison to endothelial cells of the cortical grey matter. In parallel, barrier properties of white matter CECs were superior as well. These differences might be important in the pathogenesis of diseases differently affecting distinct regions of the brain.
- Allen Brain Atlas
- blood-brain barrier (BBB)
- cerebral endothelial cell
- Copyright © 2015, American Journal of Physiology - Heart and Circulatory Physiology