Search results for "tight junctions"
showing 10 items of 30 documents
Tight Junctions as a Key for Pathogens Invasion in Intestinal Epithelial Cells
2021
Tight junctions play a major role in maintaining the integrity and impermeability of the intestinal barrier. As such, they act as an ideal target for pathogens to promote their translocation through the intestinal mucosa and invade their host. Different strategies are used by pathogens, aimed at directly destabilizing the junctional network or modulating the different signaling pathways involved in the modulation of these junctions. After a brief presentation of the organization and modulation of tight junctions, we provide the state of the art of the molecular mechanisms leading to permeability breakdown of the gut barrier as a consequence of tight junctions’ attack by pathogens, including…
Effect of three edible oils on the intestinal absorption of caffeic acid: An in vivo and in vitro study.
2016
Polyphenolic antioxidants are mainly absorbed through passive paracellular permeation regulated by tight junctions. Some fatty acids are known to modulate tight junctions. Fatty acids resulting from the digestion of edible oils may improve the absorption of polyphenolic antioxidants. Therefore, we explored the effect of three edible oils on the intestinal absorption of caffeic acid. Rats were fed with soybean oil and caffeic acid dissolved in distilled water. Caffeic acid contents in the plasma collected up to 1 hr were quantified. The experiment was repeated with coconut oil and olive oil. Component fatty acids of the oils were individually tested in vitro for their effect on permeability …
A catch-22: Interleukin-22 and cancer.
2017
Barrier surfaces of multicellular organisms are in constant contact with the environment and infractions to the integrity of epithelial surfaces is likely a frequent event. Interestingly, components of the immune system, that can be activated by environmental compounds such as the microbiota or nutrients, are interspersed among epithelial cells or directly underlie the epithelium. It is now appreciated that immune cells continuously receive and integrate signals from the environment. Curiously, such continuous reception of stimulation does not normally trigger an inflammatory response but mediators produced by immune cells in response to such signals seem to rather promote barrier integrity…
Influenza virus damages the alveolar barrier by disrupting epithelial cell tight junctions
2016
A major cause of respiratory failure during influenza A virus (IAV) infection is damage to the epithelial–endothelial barrier of the pulmonary alveolus. Damage to this barrier results in flooding of the alveolar lumen with proteinaceous oedema fluid, erythrocytes and inflammatory cells. To date, the exact roles of pulmonary epithelial and endothelial cells in this process remain unclear.Here, we used an in vitro co-culture model to understand how IAV damages the pulmonary epithelial–endothelial barrier. Human epithelial cells were seeded on the upper half of a transwell membrane while human endothelial cells were seeded on the lower half. These cells were then grown in co-culture and IAV wa…
Identification of neuronal and angiogenic growth factors in an in vitro blood-brain barrier model system: Relevance in barrier integrity and tight ju…
2016
We previously demonstrated that the co-cultivation of endothelial cells with neural cells resulted in an improved integrity of the in vitro blood-brain barrier (BBB), and that this model could be useful to evaluate the transport properties of potential central nervous system disease drugs through the microvascular brain endothelial. In this study we have used real-time PCR, fluorescent microscopy, protein arrays and enzyme-linked immunosorbent assays to determine which neural- and endothelial cell-derived factors are produced in the co-culture and improve the integrity of the BBB. In addition, a further improvement of the BBB integrity was achieved by adjusting serum concentrations and grow…
Alterations in Tight- and Adherens-Junction Proteins Related to Glaucoma Mimicked in the Organotypically Cultivated Mouse Retina Under Elevated Press…
2020
Purpose To scrutinize alterations in cellular interactions and cell signaling in the glaucomatous retina, mouse retinal explants were exposed to elevated pressure. Methods Retinal explants were prepared from C57bl6 mice and cultivated in a pressure chamber under normotensive (atmospheric pressure + 0 mm Hg), moderately elevated (30 mm Hg), and highly elevated (60 mm Hg) pressure conditions. The expression levels of proteins involved in the formation of tight junctions (zonula occludens 1 [ZO-1], occludin, and claudin-5) and adherens junctions (VE-cadherin and β-catenin) and in cell-signaling cascades (Cdc42 and activated Cdc42 kinase 1 [ACK1]), as well as the expression levels of the growth…
Anti-inflammatory and tight junction protective activity of the herbal preparation STW 5-II on mouse intestinal organoids
2021
Abstract Background Irritable bowel syndrome (IBS) is a functional bowel disorder, in which recurrent abdominal pain is associated with defecation or a change in bowel habits. STW 5-II is a combination of six medicinal herbs with a clinically proven efficacy in managing IBS. Aim This study aims to establish an in vitro IBS model using mouse intestinal organoids and to explore the anti-inflammatory and tight junction protective activities of the multi-herbal preparation STW 5-II. Methods Intestinal organoids were cultured in 1:1 Matrigel™ and medium domes. Inflammation and tight junction disruption were induced by a cocktail of cytokines (TNFα, IFNγ, IL-1β, IL-6) and bacterial proteins (LPS,…
Clostridium difficile Toxins Disrupt Epithelial Barrier Function by Altering Membrane Microdomain Localization of Tight Junction Proteins
2001
ABSTRACT The anaerobic bacterium Clostridium difficile is the etiologic agent of pseudomembranous colitis. C. difficile toxins TcdA and TcdB are UDP-glucosyltransferases that monoglucosylate and thereby inactivate the Rho family of GTPases (W. P. Ciesla, Jr., and D. A. Bobak, J. Biol. Chem. 273:16021–16026, 1998). We utilized purified reference toxins of C. difficile , TcdA-10463 (TcdA) and TcdB-10463 (TcdB), and a model intestinal epithelial cell line to characterize their influence on tight-junction (TJ) organization and hence to analyze the mechanisms by which they contribute to the enhanced paracellular permeability and disease pathophysiology of pseudomembranous colitis. The increase i…
Studying the Neurovascular Unit: An Improved Blood–Brain Barrier Model
2009
The blood–brain barrier (BBB) closely interacts with the neuronal parenchyma in vivo. To replicate this interdependence in vitro, we established a murine coculture model composed of brain endothelial cell (BEC) monolayers with cortical organotypic slice cultures. The morphology of cell types, expression of tight junctions, formation of reactive oxygen species, caspase-3 activity in BECs, and alterations of electrical resistance under physiologic and pathophysiological conditions were investigated. This new BBB model allows the application of techniques such as laser scanning confocal microscopy, immunohistochemistry, fluorescent live cell imaging, and electrical cell substrate impedance se…
The action of TH17 cells on blood brain barrier in multiple sclerosis and experimental autoimmune encephalomyelitis.
2019
Th17 cells, known as a highly pro-inflammatory subtype of Th cells, are involved very early in numerous aspects of multiple sclerosis (MS) and experimental autoimmune encephalomyelitis (EAE) neuropathology. A crucial event for the formation and accumulation of MS lesions is represented by the disruption of the blood brain barrier (BBB) in relapsing-remitting MS. Th17 cells also contribute to the progression of MS/EAE. These events will allow for the passage of inflammatory cells into the brain. Secondary to this, increased recruitment of neutrophils occurs, followed by increased protease activity that will continue to attract macrophages and monocytes, leading to brain inflammation with sus…