Differential expression of endothelial β-catenin and plakoglobin during development and maturation of the blood-brain and blood-retina barrier in the chicken

✍ Scribed by Stefan Liebner; Holger Gerhardt; Hartwig Wolburg

• Publisher: John Wiley and Sons
• Year: 2000
• Tongue: English
• Weight: 654 KB
• Volume: 217
• Category: Article
• ISSN: 1058-8388
• DOI: 10.1002/(sici)1097-0177(200001)217:1<86::aid-dvdy8>3.0.co;2-e

✦ Synopsis

The development of the bloodbrain barrier depends upon the formation of a closely regulated system of adherens and tight junctions. A prerequisite for a functional junction system is the linkage of transmembrane adhesion receptors (cadherins) to the cytoskeleton via catenins. The localization of specific catenins at the adherens junction correlates with the stability of interendothelial contacts in vitro, but in vivo data are lacking thus far. Investigating brain angiogenesis in the chicken, we demonstrated that ␤-catenin, but not plakoglobin, initially codistributed with N-cadherin at the ablumenal endothelial membrane at contact sites to perivascular cells, from where both antigens disappeared during blood-brain barrier maturation. In contrast, plakoglobin was most prominent at the interendothelial junction where only small amounts of ␤-catenin were present. Western-blot analysis revealed a stronger developmental decrease of ␤-catenin than plakoglobin, whereas N-cadherin was completely lost. ␤-Catenin but not N-cadherin was reinduced in brain endothelial cells during dedifferentiation in vitro and localized to the interendothelial junctions. These first in vivo data support the hypothesis that endothelial ␤-catenin and N-cadherin are transiently relevant for the contact of brain endothelial to perivascular cells. Plakoglobin seems not to interact with N-cadherin but is exclusively localized at interendothelial junctions providing evidence for its role in the formation of stable adherens junctions, which may play a role for the initiation, and/or stabilization of tight junctions.