scholarly journals Bile duct epithelial tight junctions and barrier function

2013 ◽  
Vol 1 (4) ◽  
pp. e25718 ◽  
Author(s):  
RK Rao ◽  
G Samak
Keyword(s):  
Bile Duct ◽  
Tight Junctions ◽  
Barrier Function ◽  
Epithelial Tight Junctions

scholarly journals Lipopolysaccharide disrupts tight junctions in cholangiocyte monolayers by a c-Src-, TLR4-, and LBP-dependent mechanism

2007 ◽  
Vol 293 (1) ◽  
pp. G308-G318 ◽  
Author(s):  
P. Sheth ◽  
N. Delos Santos ◽  
A. Seth ◽  
N. F. LaRusso ◽  
R. K. Rao
Keyword(s):  
Bile Duct ◽  
Tight Junction ◽  
Tight Junctions ◽  
Light Chain ◽  
Barrier Function ◽  
Myosin Light Chain Kinase ◽  
Myosin Light Chain ◽  
Duct Epithelium ◽  
Bile Duct Epithelium ◽  
Dependent Mechanism

Bile duct epithelium forms a barrier to the backflow of bile into the liver parenchyma. However, the structure and regulation of the tight junctions in bile duct epithelium is not well understood. In the present study, we evaluated the effect of lipopolysaccharide on tight junction integrity and barrier function in normal rat cholangiocyte monolayers. Lipopolysaccharide disrupts barrier function and increases paracellular permeability in a time- and dose-dependent manner. Lipopolysaccharide induced a redistribution of tight junction proteins, occludin, claudin-1, claudin-4, and zonula occludens (ZO)-1 from the intercellular junctions and reduced the level of ZO-1. Tyrosine kinase inhibitors (genistein and PP2) prevented lipopolysaccharide-induced increase in permeability and subcellular redistribution of ZO-1. Reduced expression of c-Src, TLR4, or LBP by specific small interfering RNA attenuated lipopolysaccharide-induced permeability and redistribution of ZO-1. ML-7, a myosin light chain kinase inhibitor, attenuated LPS-induced permeability. Lipopolysaccharide treatment rapidly increased the phosphorylation of occludin and ZO-1 on tyrosine residues, which was prevented by genistein and PP2. Occludin and ZO-1 were found to be highly phosphorylated on threonine residues in intact cell monolayers. Threonine-phosphorylation of occludin was rapidly reduced by lipopolysaccharide administration. Lipopolysaccharide-induced dephosphorylation of occludin on Thr residues was prevented by genistein and PP2. In conclusion, lipopolysaccharide disrupts the tight junction of a bile duct epithelial monolayer by a c-Src-, TLR4-, LBP-, and myosin light chain kinase-dependent mechanism.

Barrier Function of Intestinal Epithelial Tight Junctions (TJ)

1990 ◽  
pp. 27-33
Author(s):  
James L. Madara ◽  
Shirin Nash ◽  
Ronda Moore ◽  
Michael Shapiro ◽  
Susan Carlson ◽  
...  
Keyword(s):  
Tight Junctions ◽  
Barrier Function ◽  
Intestinal Epithelial ◽  
Epithelial Tight Junctions

Freeze-etch observations on the tight junctions of sertoli cells grown in organ culture with FSH

1978 ◽  
Vol 36 (2) ◽  
pp. 340-341
Author(s):  
Rita Meyer ◽  
Zoltan Posalaky ◽  
Dennis Mcginley
Keyword(s):  
Organ Culture ◽  
Tight Junctions ◽  
Sertoli Cell ◽  
Germ Cells ◽  
Sertoli Cells ◽  
Barrier Function ◽  
Cell Junction ◽  
Intramembranous Particles ◽  
Junctional Complexes ◽  
Oriented Parallel

The Sertoli cell tight junctional complexes have been shown to be the most important structural counterpart of the physiological blood-testis barrier. In freeze etch replicas they consist of extensive rows of intramembranous particles which are not only oriented parallel to one another, but to the myoid layer as well. Thus the occluding complex has both an internal and an overall orientation. However, this overall orientation to the myoid layer does not seem to be necessary to its barrier function. The 20 day old rat has extensive parallel tight junctions which are not oriented with respect to the myoid layer, and yet they are inpenetrable by lanthanum. The mechanism(s) for the control of Sertoli cell junction development and orientation has not been established, although such factors as the presence or absence of germ cells, and/or hormones, especially FSH have been implicated.

scholarly journals Trifostigmanoside I, an Active Compound from Sweet Potato, Restores the Activity of MUC2 and Protects the Tight Junctions through PKCα/β to Maintain Intestinal Barrier Function

2020 ◽  
Vol 22 (1) ◽  
pp. 291
Author(s):  
Amna Parveen ◽  
Seungho Choi ◽  
Ju-Hee Kang ◽  
Seung Hyun Oh ◽  
Sun Yeou Kim
Keyword(s):  
Tight Junctions ◽  
Sweet Potato ◽  
Barrier Function ◽  
Intestinal Barrier ◽  
Human Colon ◽  
Underlying Mechanism ◽  
Intestinal Barrier Function ◽  
Isolation And Identification ◽  
Human Colon Cancer ◽  
Mucin Production

Sweet potato (Ipomoea batata) is considered a superfood among vegetables and has been consumed for centuries. Traditionally, sweet potato is used to treat several illnesses, including diarrhea and stomach disorders. This study aimed to explore the protective effect of sweet potato on intestinal barrier function, and to identify the active compounds of sweet potato and their underlying mechanism of action. To this purpose, bioactivity-guided isolation, Western blotting, and immunostaining assays were applied. Interestingly, our bioactivity-guided approach enabled the first isolation and identification of trifostigmanoside I (TS I) from sweet potato. TS I induced mucin production and promoted the phosphorylation of PKCα/β in LS174T human colon cancer cells. In addition, it protected the function of tight junctions in the Caco-2 cell line. These findings suggest that TS I rescued the impaired abilities of MUC2, and protected the tight junctions through PKCα/β, to maintain intestinal barrier function.

scholarly journals Rab13 regulates PKA signaling during tight junction assembly

2004 ◽  
Vol 165 (2) ◽  
pp. 175-180 ◽  
Author(s):  
Katja Köhler ◽  
Daniel Louvard ◽  
Ahmed Zahraoui
Keyword(s):  
Tight Junction ◽  
Tight Junctions ◽  
Inhibitory Effect ◽  
Cell Junctions ◽  
Unknown Mechanism ◽  
Epithelial Tight Junctions ◽  
Actin Remodelling ◽  
Cell Cell

The GTPase Rab13 regulates the assembly of functional epithelial tight junctions (TJs) through a yet unknown mechanism. Here, we show that expression of the GTP-bound form of Rab13 inhibits PKA-dependent phosphorylation and TJ recruitment of the vasodilator-stimulated phosphoprotein, an actin remodelling protein. We demonstrate that Rab13GTP directly binds to PKA and inhibits its activity. Interestingly, activation of PKA abrogates the inhibitory effect of Rab13 on the recruitment of vasodilator-stimulated phosphoprotein, ZO-1, and claudin1 to cell–cell junctions. Rab13 is, therefore, the first GTPase that controls PKA activity and provides an unexpected link between PKA signaling and the dynamics of TJ assembly.

scholarly journals Alterations in alveolar epithelial tight junctions induced by chronic ethanol ingestion

2006 ◽  
Vol 20 (4) ◽  
Author(s):  
Michael Koval ◽  
Alberto L Fernandez ◽  
Pratibha C Joshi ◽  
David M Guidot
Keyword(s):  
Tight Junctions ◽  
Chronic Ethanol ◽  
Ethanol Ingestion ◽  
Alveolar Epithelial ◽  
Epithelial Tight Junctions
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