The avidin-biotinylated peroxidase complex (ABC) method was used to detect binding of 14 lectins in tissue, cultured cells, and nitrocellulose blots. When applied to frozen sections of canine cerebral cortex and pituitary and evaluated by light microscopy, these lectins produced distinct staining patterns as determined by their individual carbohydrate specificities. Major saccharide residues detected in the endothelium of these cerebral tissues include α- and β-galactose, α-mannose and/or α-glucose, and N-acetylglucosamine. Application to cells cultured from the canine cerebral endothelium gave staining results similar to those of microvessels in tissue. Thus, these characteristics of intact capillaries are retained in cultured cells and define fundamental properties of the blood-brain interface. Visual comparison of these staining patterns to those obtained for electrophoretic blots of solubilized membrane proteins identified multiple glycoprotein receptors and illustrated the vast quantity and variety of surface carbohydrate residues and the complexity of the cerebral endothelial cell glycocalyx. This carbohydrate-rich layer, which extends into the capillary lumen, may be of significant importance to the unique function of the blood-brain barrier.
Bibliographical noteFunding Information:
The authors wish to acknowledge the expert editorial assistance of Carolyn Clark and the financial assistance of the Minnesota affiliate of the American Diabetes Association. Timothy G. Myers was a participant in the Undergraduate Research Opportunities Program through the Department of Chemistry at the University of Minnesota, Duluth.
Copyright 2014 Elsevier B.V., All rights reserved.
- Blood-brain barrier
- Cerebral endothelium
- Cultured cell
- Protein blot