Transient opening of tricellular vertices controls paracellular transport through the follicle epithelium during Drosophila oogenesis

AbstractParacellular permeability is regulated to allow solute transport or migration of cells across epithelial or endothelial barriers. However, how occluding junction dynamics controls paracellular permeability is poorly understood. Here we describe patency, a developmentally regulated process in Drosophila oogenesis, during which cell vertices in the follicle epithelium open transiently to allow paracellular transport of yolk proteins for uptake by the oocyte. We show that the sequential removal of E-Cadherin, N-Cadherin, NCAM/Fasciclin-2 and Sidekick from vertices precedes their basal-to-apical opening, while the subsequent assembly of tricellular occluding junctions terminates patency and seals the paracellular barrier. E-Cadherin-based adhesion is required to limit paracellular channel size, whereas stabilized adherens junctions, prolonged NCAM/Fasciclin-2 expression, impeded endocytosis, or increased actomyosin contractility prevent patency. Our findings reveal a key role of cell vertices as gateways controlling paracellular transport, and demonstrate that the dynamic regulation of adhesion and actomyosin contractility at vertices governs epithelial barrier properties.

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l-Glutamine ameliorates acetaldehyde-induced increase in paracellular permeability in Caco-2 cell monolayer

AJP Gastrointestinal and Liver Physiology ◽

10.1152/ajpgi.00058.2004 ◽

2004 ◽

Vol 287 (3) ◽

pp. G510-G517 ◽

Cited By ~ 80

Author(s):

A. Seth ◽

S. Basuroy ◽

P. Sheth ◽

R. K. Rao

Keyword(s):

Barrier Function ◽

Egf Receptor ◽

Kinase Inhibitor ◽

Cell Monolayer ◽

Intercellular Junctions ◽

Paracellular Permeability ◽

Dependent Manner ◽

Dose Dependent ◽

E Cadherin

Role of l-glutamine in the protection of intestinal epithelium from acetaldehyde-induced disruption of barrier function was evaluated in Caco-2 cell monolayer. l-Glutamine reduced the acetaldehyde-induced decrease in transepithelilal electrical resistance and increase in permeability to inulin and lipopolysaccharide in a time- and dose-dependent manner; d-glutamine, l-aspargine, l-arginine, l-lysine, or l-alanine produced no significant protection. The glutaminase inhibitor 6-diazo-5-oxo-l-norleucine failed to affect the l-glutamine-mediated protection of barrier function. l-Glutamine reduced the acetaldehyde-induced redistribution of occludin, zonula occludens-1 (ZO-1), E-cadherin, and β-catenin from the intercellular junctions. Acetaldehyde dissociates occludin, ZO-1, E-cadherin, and β-catenin from the actin cytoskeleton, and this effect was reduced by l-glutamine. l-Glutamine induced a rapid increase in the tyrosine phosphorylation of EGF receptor, and the protective effect of l-glutamine was prevented by AG1478, the EGF-receptor tyrosine kinase inhibitor. These results indicate that l-glutamine prevents acetaldehyde-induced disruption of the tight junction and increase in the paracellular permeability in Caco-2 cell monolayer by an EGF receptor-dependent mechanism.

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Effects of 1,2-Dimethylhydrazine on Barrier Properties of Rat Large Intestine and IPEC-J2 Cells

International Journal of Molecular Sciences ◽

10.3390/ijms221910278 ◽

2021 ◽

Vol 22 (19) ◽

pp. 10278

Author(s):

Viktoria Bekusova ◽

Linda Droessler ◽

Salah Amasheh ◽

Alexander G. Markov

Keyword(s):

Colorectal Cancer ◽

Electrical Resistance ◽

Barrier Properties ◽

Acute Effect ◽

Paracellular Permeability ◽

Transepithelial Electrical Resistance ◽

Rat Colon ◽

Sodium Fluorescein ◽

Cell Monolayers

Colon cancer is accompanied by a decrease of epithelial barrier properties, which are determined by tight junction (TJ) proteins between adjacent epithelial cells. The aim of the current study was to analyze the expression of TJ proteins in a rat model of 1,2-dimethylhydrazine (DMH)-induced colorectal cancer, as well as the barrier properties and TJ protein expression of IPEC-J2 cell monolayers after incubation with DMH. Transepithelial electrical resistance and paracellular permeability for sodium fluorescein of IPEC-J2 were examined by an epithelial volt/ohm meter and spectrophotometry. The expression and localization of TJ proteins were analyzed by immunoblotting and immunohistochemistry. In the colonic tumors of rats with DMH-induced carcinogenesis, the expression of claudin-3 and -4 was significantly increased compared to controls. The transepithelial electrical resistance of IPEC-J2 cells increased, while paracellular permeability for sodium fluorescein decreased, accompanied by an increased expression of claudin-4. The increase of claudin-4 in rat colon after chronic DMH exposure was consistent with the acute effect of DMH on IPEC-J2 cells, which may indicate an essential role of this protein in colorectal cancer development.

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