Immunohistochemical localization of adherens junction components in blood-brain barrier microvessels of the rat

Abstract

The morphology and molecular composition of intercellular adherens junctions have most frequently been described in epithelial cells and the fascia adhaerens of the intercalated disc. A group of cytoplasmic molecules is known to be associated with adherens junctions. The intercellular bond is mediated by cadherins which bridge the cells by homophilic binding. Recently, endothelial cells have also been shown to form intercellular junctions of the adherens-type. However, they are morphologically less distinct and little is known about their molecular components. In this study we report the localization of some adherens junction components in intact microvessels of the blood-brain barrier in the rat. We used antibodies raised against alpha-actinin, vinculin, zyxin, cadherin (antipan-cadherin antibody) and A-CAM (N-cadherin) in immunohistochemical experiments at light and electron microscopical levels. Microvessel walls reacted positively for all antigens throughout postnatal development. All antigens were localised, though not necessarily exclusively, to interendothelial junctions. At the ultrastructural level, pan-cadherin reactivity was present throughout the entire length of the cleft. These results could mean that in blood-brain barrier endothelial cells the complex tight junction is embedded in an adherens junction which occupies the entire length of the cleft.

The protective effects of Pimavanserin against cerebral ischemia-induced brain injury

“…The junctional complexes among endothelial cells are important structures determining the integrity and are mainly composed of adherents junctions (AJ) [ 30 ], tight junctions (TJ) [ 12 ], and gap junctions (GJ) [ 31 ]. TJs span the apex of the intercellular barrier of epithelium or endothelial tissue, regulating the distance between the adjacent endothelial cells and maintaining the permeability of the vascular endothelial cell bypass [ 25 ].…”

The role and mechanism of tight junctions in the regulation of salivary gland secretion

“…For example, the fence function of TJs in the intestinal mucosa plays a crucial role in allowing some nutrients and drugs to be absorbed at apical membranes and blocking antigens from entering the systemic blood circulation (Suzuki, 2020). In the epithelium, TJs are located at the most apical portion of the lateral membranes and constitute the narrowest region of the paracellular space, whereas in the endothelium, TJs can be intermingled with AJs along the lateral membranes (Cong & Kong, 2020; Schulze & Firth, 1993). Accordingly, the distribution and/or expression pattern of AJs are usually simultaneously examined to include or exclude their contributions when referring to barrier function, especially in endothelial cells.…”

Experimental Models to Study the Functions of the Blood–Brain Barrier

“…The second region of intercellular connections, located below the region of TJs, is the zone of adhesive junctions, responsible for contact-base inhibition of cell growth, polarization of the cell layer, and to a certain degree, maintenance of BBB permeability [9]. It has also been proven that proper functioning of these junctions is required for the formation of TJs [14]. As before, the structure of this connection can be divided into transmembrane proteins (mostly cadherins and nectin) and cytoplasmic plate proteins (catenins alpha, beta and gamma) [8].…”