Tight junctions
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The skin is known to be the largest organ in human organism creating interface with outer environment. The skin provides protective barrier against pathogens, physical and chemical insults, and against uncontrolled loss of water. The barrier function was primarily attributed to the stratum corneum (SC) but recent studies confirmed that epidermal tight junctions (TJs) also play important role in maintaining barrier properties of the skin. Independent observations indicate that barrier function and its recovery is impaired in aged skin. However, trans-epidermal water loss (TEWL) values remains rather unchanged in elderly population. UV radiation as major factor of photoageing impairs TJ proteins, but TJs have great self-regenerative potential. Since it may be possible that TJs can compensate TEWL in elderly due to its regenerative and compensatory capabilities, important question remains to be answered: how are TJs regulated during skin ageing? This review provides an insight into TJs functioning as epidermal barrier and summarizes current knowledge about the impact of ageing on the barrier function of the skin and epidermal TJs.
- MeSH
- epidermis metabolismus patologie účinky záření MeSH
- kožní absorpce MeSH
- lidé MeSH
- permeabilita MeSH
- perspiratio insensibilis MeSH
- stárnutí kůže * účinky záření MeSH
- stárnutí metabolismus patologie MeSH
- těsný spoj metabolismus patologie účinky záření MeSH
- ultrafialové záření škodlivé účinky MeSH
- věkové faktory MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- přehledy MeSH
Many respiratory pathogens compromise epithelial barrier function during lung infection by disrupting intercellular junctions, such as adherens junctions and tight junctions, that maintain intercellular integrity. This includes Streptococcus pneumoniae, a leading cause of pneumonia, which can successfully breach the epithelial barrier and cause severe infections such as septicemia and meningitis. Fluorescence microscopy analysis on intercellular junction protein manipulation by respiratory pathogens has yielded major advances in our understanding of their pathogenesis. Unfortunately, a lack of automated image analysis tools that can tolerate variability in sample-sample staining has limited the accuracy in evaluating intercellular junction organization quantitatively. We have created an open source, automated Python computer script called "Intercellular Junction Organization Quantification" or IJOQ that can handle a high degree of sample-sample staining variability and robustly measure intercellular junction integrity. In silico validation of IJOQ was successful in analyzing computer generated images containing varying degrees of simulated intercellular junction disruption. Accurate IJOQ analysis was further confirmed using images generated from in vitro and in vivo bacterial infection models. When compared in parallel to a previously published, semi-automated script used to measure intercellular junction organization, IJOQ demonstrated superior analysis for all in vitro and in vivo experiments described herein. These data indicate that IJOQ is an unbiased, easy-to-use tool for fluorescence microscopy analysis and will serve as a valuable, automated resource to rapidly quantify intercellular junction disruption under diverse experimental conditions.
PURPOSE: To document the expression of apical-basal polarity (ABP) determinants in the mouse corneal epithelium (CE) and elucidate the functions of Pard3 in establishment and maintenance of ABP, stratification, homeostasis, and barrier function in the CE. METHODS: Pard3Δ/ΔC mice (Pard3LoxP/LoxP; Aldh3A1-Cre/+) with cornea-specific Pard3 ablation were generated by breeding Aldh3A1-Cre/+ with Pard3LoxP/LoxP mice. The control (Aldh3A1-Cre/+ or Pard3LoxP/LoxP alone) and Pard3Δ/ΔC corneal histology, ocular surface properties, barrier function, and actin cytoskeleton were assessed by Haematoxylin and Eosin staining of paraformaldehyde-fixed, paraffin-embedded tissues, scanning electron microscopy, fluorescein staining, and phalloidin staining, respectively. The expression of specific markers of interest was evaluated by qRT-PCR, immunoblots and immunofluorescent staining. RESULTS: Dynamic changes were observed in the expression and localization of ABP determinants as the CE stratified and matured between post-natal day 5 (PN5) and PN52. Adult Pard3Δ/ΔC CE contained fewer cell layers with rounded basal cells, and loosely adherent superficial cells lacking microplicae. Adult Pard3Δ/ΔC CE also displayed impaired barrier function with decreased expression of tight junction, adherens junction, and desmosome components, disrupted actin cytoskeletal organization, increased proliferation, and upregulation of transcription factors that drive epithelial-mesenchymal transition (EMT). CONCLUSIONS: Disruption of ABP in Pard3Δ/ΔC CE, altered expression of cell junction complex components and disorganized actin cytoskeleton, increased cell proliferation, and upregulated EMT transcription factors suggest that the ABP-determinant Pard3 promotes CE features while suppressing mesenchymal cell fate. Collectively, these results elucidate that Pard3-mediated ABP is essential for CE stratification, homeostasis and barrier function.
- MeSH
- adaptorové proteiny signální transdukční * MeSH
- cytoskelet * metabolismus MeSH
- homeostáza fyziologie MeSH
- mikroskopie elektronová rastrovací MeSH
- myši MeSH
- polarita buněk * fyziologie MeSH
- rohovkový epitel * metabolismus ultrastruktura MeSH
- těsný spoj * metabolismus fyziologie MeSH
- zvířata MeSH
- Check Tag
- myši MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
This study aimed to explore the function of Seleno-chitooligosaccharide (SOA) on the intestinal barrier through regulation of inflammatory cytokines, tight junction protein, and gut microbiota in mice. The results of ELISA assay demonstrated that SOA significantly increased the levels of IL-2, IL-10, and IFN-γ in serum and ileum. Meanwhile, SOA increased the levels of IL-4 in the ileum (p < 0.05). In addition, Diamine Oxidase (DAO) concentration was decreased in ileum by SOA treatments (p < 0.05). The administration of SOA significantly upregulated the expression of ZO-1 and Occludin in the ileum (p < 0.05). By 16S rDNA sequencing, reduced ratio of Bacillota/Bacteroidota was observed in SOA treated mice. Within the phylum of Bacteroidota, SOA increased the relative abundance of Deferribacterota, uncultured Bacteroidales bacterium, and Bacteroides. Within the phylum of Bacillota, increased relative abundance of Erysipelatoclostridium and Lachnoclostridium, and reduced relative abundance of Ruminococcaceae UCG-010 were observed with SOA supplement. In summary, SOA has the potential to modulate the function of intestinal barrier function and prevent intestinal diseases.
- MeSH
- chitin farmakologie analogy a deriváty metabolismus MeSH
- chitosan MeSH
- cytokiny * metabolismus MeSH
- funkce střevní bariéry MeSH
- ileum mikrobiologie účinky léků metabolismus MeSH
- myši MeSH
- oligosacharidy * farmakologie metabolismus MeSH
- proteiny těsného spoje * metabolismus genetika MeSH
- střevní mikroflóra * účinky léků MeSH
- střevní sliznice * metabolismus účinky léků mikrobiologie MeSH
- zvířata MeSH
- Check Tag
- mužské pohlaví MeSH
- myši MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
V posledních letech dochází k průlomovým poznatkům týkajícím se ultra-/struktury a funkce intestinální epiteliální bariéry. Současně se ukazuje, jak významná je evolučně získaná schopnost makroorganizmu dynamicky koordinovat spolupráci s komplexním kolonizujícím mikrobiálním ekosystémem pro udržení zdraví a k prevenci onemocnění. K porušení intestinální epiteliální bariéry může docházet při akutních i chronických chorobných stavech primárně infekční i neinfekční etiologie. Předkládaný přehled shrnuje aktuální znalosti o struktuře a funkci intestinální epiteliální bariéry.
In recent years, there has been a revolutionary outbreak of our knowledge about ultra-/structure and function of the intestinal epithelial barrier. During evolution acquisited ability of the macroorganism to dynamically coordinate the interaction with the complexe colonizing microbial ecosystem has been recently shown to be crucial in the health and in the illness-prevention. As acute as chronic pathological conditions, primarilly infectious or non-infectious, may lead to disruption of the intestinal epithelial barrier. The presented overview summarises actual knowledge about structure and function of the intestinal epithelial barrier. Key words: intestinal epithelial barrier – tight junctions – infection The authors declare they have no potential conflicts of interest concerning drugs, products, or services used in the study. The Editorial Board declares that the manuscript met the ICMJE „uniform requirements“ for biomedical papers. Submitted: 8. 8. 2013 Accepted: 18. 11. 2013
- Klíčová slova
- intestinální epiteliální bariéra, těsná spojení,
- MeSH
- epitelové buňky fyziologie metabolismus MeSH
- lidé MeSH
- slizniční imunita * MeSH
- střevní sliznice * fyziologie imunologie metabolismus MeSH
- těsný spoj * MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- práce podpořená grantem MeSH
- přehledy MeSH
Puwainaphycins (PUW) and minutissamides (MIN) are cyanobacterial lipopeptides found in various cyanobacterial species. The first possible target of human exposure to them is intestinal epithelium but effect of PUW/MIN on enterocytes is not known at all. Using differentiated Caco-2 cells, PUW F was found to be cytotoxic from 5 µM concentration based on lactate dehydrogenase release assay and total protein concentration. However, it is also able to induce production of interleukin 8 in non-cytotoxic concentrations 1 and 2.5 µM detected by ELISA. Effects of MIN A and C were similar but less pronounced compared to PUW F. On the other hand, MIN D was the least toxic compound with no significant pro-inflammatory effects. Surprisingly, pro-inflammatory activation of the cells by PUW F and MIN C resulted in an increase in tight junction (TJ) protein claudin 4 expression determined by western blot analysis and confirmed by confocal microscopy. Furthermore, decrease in expression of zonula occludens 3, another TJ protein, was observed after the exposure to PUW F. Taken together, these cytotoxic lipopeptides, especially PUW F, are to be studied more deeply due to their capability to activate and/or deregulate human enterocytes in low concentrations.
- MeSH
- Caco-2 buňky MeSH
- lidé MeSH
- lipopeptidy * MeSH
- sinice * MeSH
- střevní sliznice MeSH
- těsný spoj MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Intestinal milieu disorders are strongly related to the occurrence of inflammatory bowel diseases (IBDs), which results from mucosa destruction, epithelium disruption, and tight junction (TJ) proteins loss. Excess of H2 S in the intestinal milieu produced by the sulfate-reducing bacteria metabolism contributes to development of IBDs via epithelial barrier breakdown. Conventional interventions, such as surgery and anti-inflammatory medications, are considered not completely effective because of frequent recurrence and other complications. Herein, a novel oral delivery system, a hydroxypropyl methylcellulose acetate succinate (HPMCAS)-based polymer-coated Zr-based metal-organic framework (UiO-66) with a Cux -rhodamine B (CR) probe (hereinafter referred to as HUR), is produced via a co-flow microfluidic approach with the ability to reduce H2 S levels, thus restoring the intestinal lumen milieu. HPMCAS serves as an enteric coating that exposes UiO-66@CR at the pH of the intestine but not the acidic pH of the stomach. The synthesized HUR exhibits notable therapeutic efficacy, including mucosa recovery, epithelium integrity restoration, and TJ proteins upregulation via H2 S scavenging to protect against intestinal barrier damage and microbiome dysbiosis. Thus, HUR is verified to be a promising theranostic platform able to decrease the H2 S content for intestinal milieu disorder treatment. The presented study therefore opens the door for further exploitation for IBDs therapy.
Tumor cells interact with blood constituents and these interactions promote metastasis. Selectins are vascular receptors facilitating interactions of tumor cells with platelets, leukocytes, and endothelium, but the role of endothelial E-selectin remains unclear. Here we show that E-selectin is a major receptor for monocyte recruitment to tumor cell-activated endothelium. Experimental and spontaneous lung metastasis using murine tumor cells, without E-selectin ligands, were attenuated in E-selectin-deficient mice. Tumor cell-derived CCL2 promoted endothelial activation, resulting in enhanced endothelial E-selectin expression. The recruitment of inflammatory monocytes to metastasizing tumor cells was dependent on the local endothelial activation and the presence of E-selectin. Monocytes promoted transendothelial migration of tumor cells through the induction of E-selectin-dependent endothelial retractions and a subsequent modulation of tight junctions through dephosphorylation of VE-cadherin. Thus, endothelial E-selectin shapes the tumor microenvironment through the recruitment, adhesion, and activation of monocytes that facilitate tumor cell extravasation and thereby metastasis. These findings provide evidence that endothelial E-selectin is a novel factor contributing to endothelial retraction required for efficient lung metastasis. Cancer Res; 76(18); 5302-12. ©2016 AACR.
- MeSH
- CD antigeny metabolismus MeSH
- cévní endotel metabolismus MeSH
- E-selektin metabolismus MeSH
- endoteliální buňky metabolismus MeSH
- imunoblotting MeSH
- imunoprecipitace MeSH
- invazivní růst nádoru patologie MeSH
- kadheriny metabolismus MeSH
- modely nemocí na zvířatech MeSH
- monocyty metabolismus MeSH
- mutantní kmeny myší MeSH
- myši MeSH
- nádorové buněčné linie MeSH
- polymerázová řetězová reakce MeSH
- průtoková cytometrie MeSH
- těsný spoj metabolismus patologie MeSH
- transendoteliální a transepiteliální migrace fyziologie MeSH
- zvířata MeSH
- Check Tag
- myši MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
Gap junctional intercellular communication (GJIC) is an important mechanism that is involved and affected in many diseases and injuries. So far, the effect of nanosecond pulsed electric fields (nsPEFs) on the communication between cells was not investigated. An in vitro approach is presented with rat liver epithelial WB-F344 cells grown and exposed in a monolayer. In order to observe sub-lethal effects, cells were exposed to pulsed electric fields with a duration of 100ns and amplitudes between 10 and 20kV/cm. GJIC strongly decreased within 15min after treatment but recovered within 24h. Gene expression of Cx43 was significantly decreased and associated with a reduced total amount of Cx43 protein. In addition, MAP kinases p38 and Erk1/2, involved in Cx43 phosphorylation, were activated and Cx43 became hyperphosphorylated. Immunofluorescent staining of Cx43 displayed the disassembly of gap junctions. Further, a reorganization of the actin cytoskeleton was observed whereas tight junction protein ZO-1 was not significantly affected. All effects were field- and time-dependent and most pronounced within 30 to 60min after treatment. A better understanding of a possible manipulation of GJIC by nsPEFs might eventually offer a possibility to develop and improve treatments.
- MeSH
- aktiny metabolismus MeSH
- aktivace enzymů MeSH
- buněčné linie MeSH
- časové faktory MeSH
- elektřina * MeSH
- fosforylace MeSH
- konexin 43 genetika metabolismus MeSH
- krysa rodu rattus MeSH
- mezerový spoj metabolismus MeSH
- mezibuněčná komunikace * MeSH
- mitogenem aktivovaná proteinkinasa 1 metabolismus MeSH
- mitogenem aktivovaná proteinkinasa 3 metabolismus MeSH
- mitogenem aktivované proteinkinasy p38 metabolismus MeSH
- protein zonula occludens 1 metabolismus MeSH
- regulace genové exprese MeSH
- viabilita buněk MeSH
- zvířata MeSH
- Check Tag
- krysa rodu rattus MeSH
- mužské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
OBJECTIVES: The Caco-2 cell monolayer model is widely used as a standard screening tool for studying the mechanisms of cellular drug transport. Caffeine was chosen as a model drug and is supposed to be class I of the Biopharmaceutics Classification System (BCS). Our study was conducted 1) to characterize the mechanisms of caffeine transport across the intestinal barrier, 2) to classify caffeine according to BCS, 3) to predict drugs intestinal absorption in humans. METHODS: Caffeine transport (0.1, 0.3, 1 and 10 mmol/l) was studied in Caco-2 cell monolayer in apical to basolateral (AP-BL) and basolateral to apical (BL-AP) direction, under iso-pH 7.4 and pH-gradient (6/7.4) conditions. The relative contribution of the paracellular route was estimated using Ca2+- free transport medium (opening tight junctions). RESULTS: The caffeine transport was linear with time, transport direction and pH independent, displaying non-saturable (first-order) kinetics, with high permeability coefficient (Papp): in AP-BL direction Papp = 46.3-53.5 x 10-6 cm/s; in BL-AP direction Papp = 45.6-49.4 x 10-6 cm/s. Thus, the transport seems to be transcellular mediated by passive diffusion. Using Ca2+- free transport medium tight junctions were opened (confirmed by increased Papp of mannitol) but the caffeine Papp was not changed. Thus, the paracellular route is only a minor way of caffeine transport. CONCLUSION: High solubility and high permeability of caffeine rank it among class I of BCS and well absorbed compounds.
- MeSH
- biologický transport účinky léků fyziologie MeSH
- buněčné kultury MeSH
- Caco-2 buňky MeSH
- difuze MeSH
- intestinální absorpce MeSH
- kinetika MeSH
- kofein farmakokinetika farmakologie MeSH
- koncentrace vodíkových iontů MeSH
- lidé MeSH
- lineární modely MeSH
- mannitol metabolismus MeSH
- permeabilita účinky léků MeSH
- střevní sliznice metabolismus MeSH
- těsný spoj účinky léků metabolismus MeSH
- viabilita buněk účinky léků MeSH
- xenobiotika farmakokinetika farmakologie MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
