Tight junction barrier function

Chen Y, Merzdorf C, Paul DL, Goodenough DA (1997) COOH terminus of occludin is required for tight junction barrier function in early Xenopus embryos. J Cell Biol 138 891-899... 

PURPOSE AND RATIONALE This test uses the ex vivo model of comeal organ culture previously discussed combined with surface biotinylation technique. The comeal epithelium functions as a barrier that separates the internal ocular tissues from the external environment and is therefore vulnerable to chemical insult (Gipson and Sugrue 1994). The joint assessment of comeal organ culture and surface biotinylation is a measure of ocular toxicity that is intended to reveal disrupted tight junction barriers following chemical exposure. 

Baida MS, Whitney JA, Flores C, Gonzalez-Mariscal L, Cereijido M, and Matter K [1996] Functional dissociation of paracellular permeability and transepithelial electrical resistance and disruption of the apical-basolateral intramembrane diffusion barrier by the expression of a mutant tight junction membrane protein. J Cell Biol 134 1031-1049... 

Yoo J, Nichols A, Mammen J, Calvo I, Song JC, Worrell RT, Matlin K, and Matthews JB [2003] Bryostatin-1 enhances barrier function in T84 epithelia through PKC-dependent regulation of tight junction proteins. Am J Physiol 285 C300-C309... 

The blood-brain barrier forms the interface between the bloodstream and the brain parenchyma and thus controls the passage of endogenous substances and xenobiotics into and out of the central nervous system. Brain microvessels exhibit a variety of unique structural features, such as an extremely tight endothelium without fenestration, a very low rate of pinocytosis, tight junctions between endothelial cells excluding paracellular permeability, and a series of polarized transport proteins. The following chapter describes the structural and functional characteristics of the blood-brain barrier with emphasis on transport proteins, as well as in vitro techniques, which allow studying this complex barrier in the brain. 

Tire brain, which must function in a chemically stable environment, is protected by a tough outer covering, the arachnoid membrane, and by the blood-brain barrier406 407 and the blood-cerebrospinal barrier. Both of these barriers consist of tight junctions similar to those seen in Fig. 1-15A. They are formed between the endothelial cells of the cerebral capillaries and between the epithelial cells that surround the capillaries of the choroid plexus. The choroid plexus consists of capillary beds around portions... 

Harhaj NS, Antonetti DA. Regulation of tight junctions and loss of barrier function in pathophysiology. International Journal of Biochemistry and Cell Biology 2004, 36, 1206-1237. 

Water homeostasis is a strict requirement for normal physiological function. The most important task of the human skin is thus to create a watertight enclosure of the body to prevent water loss. It is the intercellular lipid matrix of the outermost keratinized horny layer of the skin (possibly together with recently reported claudin-based tight-junctions Furuse et al., 2002) that represents the skin barrier proper as once this lipid matrix (composed foremostly of saturated long chain ceramides ( 50% wt/wt) and cholesterol (—30% wt/wt) (Wertz and Norlen, 2002)) has been removed, substances diffuse freely into or out of the body system (Blank, 1952 Breathnach et al., 1973 Elias and Friend, 1975). At the same time the intercellular lipid matrix ensures that the stratum corneum remains hydrated and thus the skin surface appears healthy and smooth. 

E. coli strain Nissle 1917 Improves epithelial barrier function Increases tight junction protein expression, ZO-2 Zyrek et al. (2007)... 

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