ZO-1 interacts with claudins, occluding, and actin (Turner, 2009), and plays an important role in structural organization of tight junctions
(Stevenson et al.
1994) proposed that the mechanism of absorption enhancement was a combination of mucoadhe-sion and a loosening effect on the tension of the tight junctions
through ionic interactions with negatively charged groups of glycocalix.
Our findings challenge the belief that the top layer of the skin or stratum corneum is the sole barrier structure: It suggests that both the stratum corneum and tight junctions
need to be defective to jumpstart the disease," she added.
The tight junctions
(TJs) limit passive paracellular movement of solutes, ions, and water across the BBB.
Development of tight junctions
de novo in the mouse early embryo: control of assembly of the tight junction
Uremic plasma impairs barrier function and depletes the tight junction
protein constituents of intestinal epithelium.
A high-fat diet may impair mucus production and decrease expression of the tight junction
proteins, contributing to greater intestinal permeability.
ZO-2 silencing in epithelial cells perturbs the gate and fence function of tight junctions
and leads to an atypical monolayer architecture.
Claudins are tetraspan membrane proteins essential components of the paracelular barriers found in tight junctions
of all epithelia and endothelia which contain a longer intracellular C-terminus through which the majority of human claudins interact with PDZ domains of various proteins (Gunzel & Yu, 2013).
The BBB is a system of cells and membranes that form tight junctions
to prevent harmful agents that circulate in the bloodstream from entering the brain.
The short answer is by disrupting the epithelial cells themselves (transepithelial permeability) and by disrupting the spaces between the epithelial cells (paracellular permeability), which consist of tight junctions
, the cytoskeleton, and several associated proteins (see figure below).
In the presence of zonulin, the normally tight junctions
between the intestinal cells remain open.