scholarly journals COOH Terminus of Occludin Is Required for Tight Junction Barrier Function in Early Xenopus Embryos

1997 ◽  
Vol 138 (4) ◽  
pp. 891-899 ◽  
Author(s):  
Yan-hua Chen ◽  
Christa Merzdorf ◽  
David L. Paul ◽  
Daniel A. Goodenough
Keyword(s):  
Tight Junction ◽  
Tight Junctions ◽  
Barrier Function ◽  
Integral Membrane Protein ◽  
Full Length ◽  
Intercellular Spaces ◽  
Zonula Occludens ◽  
Zonula Occludens 1 ◽  
First Time

Occludin is the only known integral membrane protein localized at the points of membrane– membrane interaction of the tight junction. We have used the Xenopus embryo as an assay system to examine: (a) whether the expression of mutant occludin in embryos will disrupt the barrier function of tight junctions, and (b) whether there are signals within the occludin structure that are required for targeting to the sites of junctional interaction. mRNAs transcribed from a series of COOH-terminally truncated occludin mutants were microinjected into the antero–dorsal blastomere of eight-cell embryos. 8 h after injection, the full-length and the five COOH-terminally truncated proteins were all detected at tight junctions as defined by colocalization with both endogenous occludin and zonula occludens-1 demonstrating that exogenous occludin correctly targeted to the tight junction. Importantly, our data show that tight junctions containing four of the COOH-terminally truncated occludin proteins were leaky; the intercellular spaces between the apical cells were penetrated by sulfosuccinimidyl-6-(biotinamido) Hexanoate (NHS-LC-biotin). In contrast, embryos injected with mRNAs coding for the full-length, the least truncated, or the soluble COOH terminus remained impermeable to the NHS-LC-biotin tracer. The leakage induced by the mutant occludins could be rescued by coinjection with full-length occludin mRNA. Immunoprecipitation analysis of detergent-solubilized embryo membranes revealed that the exogenous occludin was bound to endogenous Xenopus occludin in vivo, indicating that occludin oligomerized during tight junction assembly. Our data demonstrate that the COOH terminus of occludin is required for the correct assembly of tight junction barrier function. We also provide evidence for the first time that occludin forms oligomers during the normal process of tight junction assembly. Our data suggest that mutant occludins target to the tight junction by virtue of their ability to oligomerize with full-length endogenous molecules.

scholarly journals Inhibiting Connexin43/Zonula Occludens‐1 Interactions Improves Alcoholic Lung Barrier Function in vivo

2021 ◽  
Vol 35 (S1) ◽  
Author(s):  
Lauren Jeffers ◽  
Carissa James ◽  
Ryan Reed ◽  
Michael Koval
Keyword(s):  
Barrier Function ◽  
Zonula Occludens ◽  
Zonula Occludens 1

Copper treatment alters the permeability of tight junctions in cultured human intestinal Caco-2 cells

1999 ◽  
Vol 277 (6) ◽  
pp. G1138-G1148 ◽  
Author(s):  
Simonetta Ferruzza ◽  
Maria-Laura Scarino ◽  
Giuseppe Rotilio ◽  
Maria Rosa Ciriolo ◽  
Paolo Santaroni ◽  
...  
Keyword(s):  
Tight Junction ◽  
Tight Junctions ◽  
Electrical Resistance ◽  
Transepithelial Electrical Resistance ◽  
Complete Medium ◽  
Zonula Occludens ◽  
Intracellular Effect ◽  
Tight Junction Permeability ◽  
Zonula Occludens 1 ◽  
Effect Of Copper

The effects of copper on tight-junction permeability were investigated in human intestinal Caco-2 cells, monitoring transepithelial electrical resistance and transepithelial passage of mannitol. Apical treatment of Caco-2 cells with 10–100 μM CuCl2(up to 3 h) produced a time- and concentration-dependent increase in tight-junction permeability, reversible after 24 h in complete medium in the absence of added copper. These effects were not observed in cells treated with copper complexed to l-histidine [Cu(His)2]. The copper-induced increase in tight-junction permeability was affected by the pH of the apical medium, as was the apical uptake of64CuCl2, both exhibiting a maximum at pH 6.0. Treatment with CuCl2produced a concentration-dependent reduction in the staining of F actin but not of the junctional proteins zonula occludens-1, occludin, and E-cadherin and produced ultrastructural alterations to microvilli and tight junctions that were not observed after treatment with up to 200 μM Cu(His)2for 3 h. Overall, these data point to an intracellular effect of copper on tight junctions, mediated by perturbations of the F actin cytoskeleton.

scholarly journals Tight junction protein ZO-1 in Kawasaki disease

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Wan-Tz Lai ◽  
Hung-Chang Lee ◽  
Ying-Hsien Huang ◽  
Mao-Hung Lo ◽  
Ho-Chang Kuo
Keyword(s):  
Kawasaki Disease ◽  
Tight Junction ◽  
Tight Junctions ◽  
Statistical Significance ◽  
Intestinal Barrier ◽  
Serum Levels ◽  
Ivig Treatment ◽  
Enzyme Linked Immunosorbent Assay ◽  
Zonula Occludens ◽  
Zonula Occludens 1

Abstract Background Kawasaki disease (KD) is a form of systemic febrile vasculitis that is complicated with coronary artery lesions (CAL). The tight junctions that maintain the intestinal barrier also play a role in systemic inflammatory diseases. Serum zonula occludens-1 (ZO-1) expression was found to be significantly lower in asthmatic patients, and another study reported that elevated systemic ZO-1 was positively correlated with inflammation in cirrhotic patients. A murine model of KD vasculitis demonstrated that vasculitis depended on intestinal barrier dysfunction, which is maintained by tight junctions. In this study, we aimed to investigate the role of the tight junction zonula occludens-1 (ZO-1) in the treatment response of intravenous immunoglobulin (IVIG) and the occurrence of CAL formation in KD patients. Methods We enrolled 40 KD patients, 12 healthy controls, and 12 febrile controls in this study. The serum levels of tight junction ZO-1 were determined by enzyme-linked immunosorbent assay. Results The serum ZO-1 level was higher in the fever control group but did not reach a statistical significance. KD patients who received a second dose of IVIG treatment due to initial IVIG unresponsiveness had a higher serum levels of tight junction ZO-1, but without statistical significance (2.15 ± 0.18 vs. 2.69 ± 0.31 ng/mL, p = 0.058). KD patients who developed a CAL demonstrated a significant lower serum tight junction ZO-1 levels than KD without CAL formation (1.89 ± 0.16 vs. 2.39 ± 0.15 ng/mL, p = 0.027). After multiple logistic regression analysis, ZO-1 levels [(95% confidence interval (CI): 0.058 ~ 0.941, odds ratio (OR) = 0.235, p = 0.041)] showed as the risk factor for CAL formation. Conclusion Serum levels of tight junction ZO-1 levels were lower in KD patients than fever controls and associated with CAL formation.

scholarly journals Direct Current Stimulation Disrupts Endothelial Glycocalyx and Tight Junctions of the Blood-Brain Barrier in vitro

2021 ◽  
Vol 9 ◽  
Author(s):  
Yifan Xia ◽  
Yunfei Li ◽  
Wasem Khalid ◽  
Marom Bikson ◽  
Bingmei M. Fu
Keyword(s):  
Endothelial Cells ◽  
Tight Junction ◽  
Tight Junctions ◽  
Blood Brain Barrier ◽  
Direct Current ◽  
Endothelial Glycocalyx ◽  
Microvascular Endothelial Cells ◽  
Bbb Permeability

Transcranial direct current stimulation (tDCS) is a non-invasive physical therapy to treat many psychiatric disorders and to enhance memory and cognition in healthy individuals. Our recent studies showed that tDCS with the proper dosage and duration can transiently enhance the permeability (P) of the blood-brain barrier (BBB) in rat brain to various sized solutes. Based on the in vivo permeability data, a transport model for the paracellular pathway of the BBB also predicted that tDCS can transiently disrupt the endothelial glycocalyx (EG) and the tight junction between endothelial cells. To confirm these predictions and to investigate the structural mechanisms by which tDCS modulates P of the BBB, we directly quantified the EG and tight junctions of in vitro BBB models after DCS treatment. Human cerebral microvascular endothelial cells (hCMECs) and mouse brain microvascular endothelial cells (bEnd3) were cultured on the Transwell filter with 3 μm pores to generate in vitro BBBs. After confluence, 0.1–1 mA/cm2 DCS was applied for 5 and 10 min. TEER and P to dextran-70k of the in vitro BBB were measured, HS (heparan sulfate) and hyaluronic acid (HA) of EG was immuno-stained and quantified, as well as the tight junction ZO-1. We found disrupted EG and ZO-1 when P to dextran-70k was increased and TEER was decreased by the DCS. To further investigate the cellular signaling mechanism of DCS on the BBB permeability, we pretreated the in vitro BBB with a nitric oxide synthase (NOS) inhibitor, L-NMMA. L-NMMA diminished the effect of DCS on the BBB permeability by protecting the EG and reinforcing tight junctions. These in vitro results conform to the in vivo observations and confirm the model prediction that DCS can disrupt the EG and tight junction of the BBB. Nevertheless, the in vivo effects of DCS are transient which backup its safety in the clinical application. In conclusion, our current study directly elucidates the structural and signaling mechanisms by which DCS modulates the BBB permeability.

scholarly journals Decreased ZO1 expression causes loss of time-dependent tight junction function in the liver of ob/ob mice

2021 ◽  
Author(s):  
Yuya Tsurudome ◽  
Nao Morita ◽  
Michiko Horiguchi ◽  
Kentaro Ushijima
Keyword(s):  
Tight Junction ◽  
Dark Period ◽  
Vital Role ◽  
Time Dependent ◽  
Signal Transduction System ◽  
Binding Ability ◽  
Protein Levels ◽  
Multiple Organs ◽  
Zonula Occludens ◽  
Zonula Occludens 1

Abstract Diabetes patients are at a high risk of developing complications related to angiopathy and disruption of the signal transduction system. The liver is one of the multiple organs damaged during diabetes. Few studies have evaluated the morphological effects of adhesion factors in diabetic liver. The influence of diurnal variation has been observed in the expression and functioning of adhesion molecules to maintain tissue homeostasis associated with nutrient uptake. The present study demonstrated that the rhythm-influenced functioning of tight junction was impaired in the liver of ob/ob mice. The tight junctions of hepatocytes were loosened during the dark period in normal mice compared to those in ob/ob mice, where the hepatocyte gaps remained open throughout the day. The time-dependent expression of zonula occludens 1 (ZO1) in the liver plays a vital role in the functioning of the tight junction. The time-dependent expression of ZO1 was nullified and its expression was attenuated in the liver of ob/ob mice. ZO1 expression was inhibited at the mRNA and protein levels. The expression rhythm of ZO1 was found to be regulated by heat shock factor (HSF)1/2, the expression of which was reduced in the liver of ob/ob mice. The DNA-binding ability of HSF1/2 was decreased in the liver of ob/ob mice compared to that in normal mice. These findings suggest the involvement of impaired expression and functioning of adhesion factors in diabetic liver complications.

scholarly journals Symplekin, a novel type of tight junction plaque protein.

1996 ◽  
Vol 134 (4) ◽  
pp. 1003-1018 ◽  
Author(s):  
B H Keon ◽  
S Schäfer ◽  
C Kuhn ◽  
C Grund ◽  
W W Franke
Keyword(s):  
Tight Junction ◽  
Tight Junctions ◽  
Sertoli Cells ◽  
Light And Electron Microscopy ◽  
Cell Types ◽  
Calculated Molecular Weight ◽  
Zonula Occludens ◽  
Cytoplasmic Face ◽  
Wide Range ◽  
Vascular Endothelia

Using a monoclonal antibody we have identified and cDNA-cloned a novel type of protein localized, by light and electron microscopy, to the plaque associated with the cytoplasmic face of the tight junction-containing zone (zonula occludens) of polar epithelial cells and of Sertoli cells of testis, but absent from the junctions of vascular endothelia. The approximately 3.7-kb mRNA encodes a polypeptide of 1142 amino acids (calculated molecular weight 126.5 kD, pI 6.25), for which the name "symplekin" (from Greek sigma upsilon mu pi lambda epsilon kappa epsilon iota, nu, to tie together, to weave, to be intertwined) is proposed. However, both the mRNA and the protein can also be detected in a wide range of cell types that do not form tight junctions or are even completely devoid of any stable cell contacts. Careful analyses have revealed that the protein occurs in all these diverse cells in the nucleoplasm, and only in those cells forming tight junctions is it recruited, partly but specifically, to the plaque structure of the zonula occludens. We discuss symplekin as a representative of a group of dual residence proteins which occur and probably function in the nucleus as well as in the plaques exclusive for either tight junctions, adherens junctions, or desmosomes.

Modulation of tight junction structure in blood-brain barrier endothelial cells. Effects of tissue culture, second messengers and cocultured astrocytes

1994 ◽  
Vol 107 (5) ◽  
pp. 1347-1357 ◽  
Author(s):  
H. Wolburg ◽  
J. Neuhaus ◽  
U. Kniesel ◽  
B. Krauss ◽  
E.M. Schmid ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Tight Junction ◽  
Tight Junctions ◽  
Blood Brain Barrier ◽  
Barrier Function ◽  
Primary Cultures ◽  
Brain Barrier ◽  
Brain Endothelial Cells ◽  
Blood Brain ◽  
Camp Levels

Tight junctions between endothelial cells of brain capillaries are the most important structural elements of the blood-brain barrier. Cultured brain endothelial cells are known to loose tight junction-dependent blood-brain barrier characteristics such as macromolecular impermeability and high electrical resistance. We have directly analyzed the structure and function of tight junctions in primary cultures of bovine brain endothelial cells using quantitative freeze-fracture electron microscopy, and ion and inulin permeability. The complexity of tight junctions, defined as the number of branch points per unit length of tight junctional strands, decreased 5 hours after culture but thereafter remained almost constant. In contrast, the association of tight junction particles with the cytoplasmic leaflet of the endothelial membrane bilayer (P-face) decreased continuously with a major drop between 16 hours and 24 hours. The complexity of tight junctions could be increased by elevation of intracellular cAMP levels while phorbol esters had the opposite effect. On the other hand, the P-face association of tight junction particles was enhanced by elevation of cAMP levels and by coculture of endothelial cells with astrocytes or exposure to astrocyte-conditioned medium. The latter effect on P-face association was induced by astrocytes but not fibroblasts. Elevation of cAMP levels together with astrocyte-conditioned medium synergistically increased transendothelial electrical resistance and decreased inulin permeability of primary cultures, thus confirming the effects on tight junction structure and barrier function. P-face association of tight junction particles in brain endothelial cells may therefore be a critical feature of blood-brain barrier function that can be specifically modulated by astrocytes and cAMP levels. Our results suggest an important functional role for the cytoplasmic anchorage of tight junction particles for brain endothelial barrier function in particular and probably paracellular permeability in general.

Human zonulin, a potential modulator of intestinal tight junctions

2000 ◽  
Vol 113 (24) ◽  
pp. 4435-4440 ◽  
Author(s):  
W. Wang ◽  
S. Uzzau ◽  
S.E. Goldblum ◽  
A. Fasano
Keyword(s):  
Tight Junction ◽  
Tight Junctions ◽  
Ussing Chamber ◽  
Intestinal Lumen ◽  
Epithelial Surface ◽  
Ussing Chambers ◽  
Zonula Occludens ◽  
Surface Receptor ◽  
Dynamic Structures ◽  
Zonula Occludens Toxin

Intercellular tight junctions are dynamic structures involved in vectorial transport of water and electrolytes across the intestinal epithelium. Zonula occludens toxin derived from Vibrio cholerae interacts with a specific intestinal epithelial surface receptor, with subsequent activation of a complex intracellular cascade of events that regulate tight junction permeability. We postulated that this toxin may mimic the effect of a functionally and immunologically related endogenous modulator of intestinal tight junctions. Affinity-purified anti-zonula occludens toxin antibodies and the Ussing chamber assay were used to screen for one or more mammalian zonula occludens toxin analogues in both fetal and adult human intestine. A novel protein, zonulin, was identified that induces tight junction disassembly in non-human primate intestinal epithelia mounted in Ussing chambers. Comparison of amino acids in the active zonula occludens toxin fragment and zonulin permitted the identification of the putative receptor binding domain within the N-terminal region of the two proteins. Zonulin likely plays a pivotal role in tight junction regulation during developmental, physiological, and pathological processes, including tissue morphogenesis, movement of fluid, macromolecules and leukocytes between the intestinal lumen and the interstitium, and inflammatory/autoimmune disorders.

scholarly journals High dose of baicalin or baicalein can reduce tight junction integrity by partly targeting the first PDZ domain of zonula occludens-1 (ZO-1)

2020 ◽  
Vol 887 ◽  
pp. 173436 ◽  
Author(s):  
Misaki Hisada ◽  
Minami Hiranuma ◽  
Mio Nakashima ◽  
Natsuko Goda ◽  
Takeshi Tenno ◽  
...  
Keyword(s):  
Tight Junction ◽  
Pdz Domain ◽  
High Dose ◽  
Zonula Occludens ◽  
Zonula Occludens 1
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