scholarly journals 1-Naphthylisothiocyanate-induced permeability of hepatic tight junctions to proteins

1986 ◽  
Vol 238 (2) ◽  
pp. 323-328 ◽  
Author(s):  
K S Kan ◽  
R Coleman
Keyword(s):  
Tight Junctions ◽  
Bile Flow ◽  
Gamma Globulin ◽  
Oxidase Inhibitor ◽  
Permeability Barrier ◽  
Permeability Change ◽  
Bile Sample ◽  
Small Peak ◽  
Early Action ◽  
Junctional Permeability

We have studied the early action of 1-naphthylisothiocyanate (ANIT) in relation to its effect on the permeability barrier formed by hepatic tight junctions. Materials having different Mr values [inulin (5000), horseradish peroxidase (HRP) (40,000), ovalbumin (also 40,000) and pig gamma-globulin (IgG) (160,000)] were individually pulsed, within 1 min, into perfused rat livers operating under single-pass conditions. In untreated rats, a small peak of HRP and ovalbumin and a comparatively larger peak of inulin were observed in the bile at 7 min. In rats treated with ANIT, with increasing duration of ANIT treatment the inulin peak increased proportionally, whereas the HRP and ovalbumin peaks remained unchanged until after 10 h of ANIT exposure; gamma-globulin was not detected in the 7 min bile sample until after 14 h of ANIT treatment. Bile flow in all rats remained approximately the same until after 14 h of ANIT pretreatment, when substantial bile-flow reduction was observed. Phenobarbitone pretreatment increased the effect of ANIT and massively elevated the first HRP peak; it also shortened the time (to 4 h) at which the increase in permeability to this protein was observed. In contrast, the first HRP peak was virtually abolished in rats that had received the mixed-function-oxidase inhibitor SKF 525A. These experiments suggest that (i) ANIT progressively increased the permeability of the junctional barrier before the reduction in bile flow, (ii) the ANIT-increased permeability change seems to be inversely dependent upon the Mr of the infused proteins, and (iii) metabolites of ANIT were involved in the development of the junctional permeability change.

scholarly journals MarvelD3 couples tight junctions to the MEKK1–JNK pathway to regulate cell behavior and survival

2014 ◽  
Vol 204 (5) ◽  
pp. 821-838 ◽  
Author(s):  
Emily Steed ◽  
Ahmed Elbediwy ◽  
Barbara Vacca ◽  
Sébastien Dupasquier ◽  
Sandra A. Hemkemeyer ◽  
...  
Keyword(s):  
Tight Junctions ◽  
Tumor Cell Line ◽  
Metastatic Tumor ◽  
Tumor Formation ◽  
Cell Behavior ◽  
Permeability Barrier ◽  
Jnk Pathway ◽  
Junctional Permeability ◽  
Jnk Activation

MarvelD3 is a transmembrane component of tight junctions, but there is little evidence for a direct involvement in the junctional permeability barrier. Tight junctions also regulate signaling mechanisms that guide cell proliferation; however, the transmembrane components that link the junction to such signaling pathways are not well understood. In this paper, we show that MarvelD3 is a dynamic junctional regulator of the MEKK1–c-Jun NH2-terminal kinase (JNK) pathway. Loss of MarvelD3 expression in differentiating Caco-2 cells resulted in increased cell migration and proliferation, whereas reexpression in a metastatic tumor cell line inhibited migration, proliferation, and in vivo tumor formation. Expression levels of MarvelD3 inversely correlated with JNK activity, as MarvelD3 recruited MEKK1 to junctions, leading to down-regulation of JNK phosphorylation and inhibition of JNK-regulated transcriptional mechanisms. Interplay between MarvelD3 internalization and JNK activation tuned activation of MEKK1 during osmotic stress, leading to junction dissociation and cell death in MarvelD3-depleted cells. MarvelD3 thus couples tight junctions to the MEKK1–JNK pathway to regulate cell behavior and survival.

Localization of a novel 210 kDa protein in Xenopus tight junctions

1997 ◽  
Vol 110 (8) ◽  
pp. 1005-1012 ◽  
Author(s):  
C.S. Merzdorf ◽  
D.A. Goodenough
Keyword(s):  
Monoclonal Antibody ◽  
Epithelial Cells ◽  
Tight Junction ◽  
Tight Junctions ◽  
Basolateral Membrane ◽  
Immunofluorescent Staining ◽  
Junctional Complex ◽  
Permeability Barrier ◽  
Membrane Domains ◽  
Kidney Liver

The tight junction is the most apical member of the intercellular junctional complex. It functions as a permeability barrier between epithelial cells and maintains the integrity of the apical and basolateral membrane domains. In order to study tight junctions in Xenopus laevis, a polyclonal antibody was raised which recognized Xenopus ZO-1. Monoclonal antibody 19B1 (mAb 19B1) was generated in rats using a crude membrane preparation from Xenopus lung as antigen. mAb 19B1 gave immunofluorescent staining patterns identical to those seen with anti-ZO-1 on monolayers of Xenopus A6 kidney epithelial cells and on frozen sections of Xenopus kidney, liver, and embryos. Electron microscopy showed that the 19B1 antigen colocalized with ZO-1 at the tight junction. Western blotting and immunoprecipitation demonstrated that ZO-1 is an approximately 220 kDa protein in Xenopus, while mAb 19B1 identified an approximately 210 kDa antigen on immunoblots. Immunoprecipitates of ZO-1 were not recognized by mAb 19B1 by western analysis. The solubility properties of the 19B1 antigen suggested that it is a peripheral membrane protein. Thus, the antigen recognized by the new monoclonal antibody 19B1 is not ZO-1 and represents a different Xenopus tight junction associated protein.

Disruption of guinea pig urinary bladder permeability barrier in noninfectious cystitis

1998 ◽  
Vol 274 (1) ◽  
pp. F205-F214 ◽  
Author(s):  
John P. Lavelle ◽  
Gerard Apodaca ◽  
Susan A. Meyers ◽  
Wily G. Ruiz ◽  
Mark L. Zeidel
Keyword(s):  
Tight Junctions ◽  
Apical Membrane ◽  
Bladder Wall ◽  
Permeability Barrier ◽  
Structural Effects ◽  
Bladder Pain ◽  
Ussing Chambers ◽  
Apical Membranes ◽  
Umbrella Cells ◽  
Saline Vehicle

Although most cell membranes permit rapid flux of water, small nonelectrolytes, and ammonia, the apical membranes of bladder epithelial umbrella cells, which form the bladder permeability barrier, exhibit strikingly low permeabilities to these substances. In cystitis, disruption of the bladder permeability barrier may irritate the bladder wall layers underlying the epithelium, causing or exacerbating inflammation, and increasing urinary frequency, urgency, and bladder pain. To determine the effects of inflammation on the integrity of the permeability barrier, guinea pigs were sensitized with ovalbumin, and the bladders were exposed subsequently to antigen by instillation on the urinary side. Inflammation of the bladder wall markedly reduced transepithelial resistance of dissected epithelium mounted in Ussing chambers and increased water and urea permeabilities modestly at 2 h and more strikingly at 24 h after induction of the inflammation. Transmission and scanning electron microscopy of bladders at 30 min and 24 h after antigen exposure revealed disruption of tight junctions, denuding of patches of epithelium, and occasional loss of apical membrane architecture. These permeability and structural effects did not occur in nonsensitized animals in which the bladders were exposed to antigen and in sensitized animals exposed to saline vehicle rather than antigen. These results demonstrate that inflammation of the underlying muscle and lamina propria can disrupt the bladder permeability barrier by damaging tight junctions and apical membranes and causing sloughing of epithelial cells. Leakage of urinary constituents through the damaged epithelium may then exacerbate the inflammation in the underlying muscle layers.

scholarly journals Connexin-Occludin Chimeras Containing the Zo-Binding Domain of Occludin Localize at Mdck Tight Junctions and Nrk Cell Contacts

1999 ◽  
Vol 146 (3) ◽  
pp. 683-693 ◽  
Author(s):  
Laura L. Mitic ◽  
Eveline E. Schneeberger ◽  
Alan S. Fanning ◽  
James Melvin Anderson
Keyword(s):  
Tight Junction ◽  
Tight Junctions ◽  
Mdck Cells ◽  
Transmembrane Protein ◽  
Rat Kidney ◽  
Freeze Fracture ◽  
Binding Domain ◽  
Permeability Barrier ◽  
Cell Contacts ◽  
Cytoplasmic Proteins

Occludin is a transmembrane protein of the tight junction that functions in creating both an intercellular permeability barrier and an intramembrane diffusion barrier. Creation of the barrier requires the precise localization of occludin, and a distinct family of transmembrane proteins called claudins, into continuous linear fibrils visible by freeze-fracture microscopy. Conflicting evidence exists regarding the relative importance of the transmembrane and extracellular versus the cytoplasmic domains in localizing occludin in fibrils. To specifically address whether occludin's COOH-terminal cytoplasmic domain is sufficient to target it into tight junction fibrils, we created chimeras with the transmembrane portions of connexin 32. Despite the gap junction targeting information present in their transmembrane and extracellular domains, these connexin-occludin chimeras localized within fibrils when expressed in MDCK cells, as assessed by immunofluorescence and immunogold freeze-fracture imaging. Localization of chimeras at tight junctions depends on the COOH-terminal ZO-binding domain and not on the membrane proximal domain of occludin. Furthermore, neither endogenous occludin nor claudin is required for targeting to ZO-1–containing cell–cell contacts, since in normal rat kidney fibroblasts targeting of chimeras again required only the ZO-binding domain. These results suggest an important role for cytoplasmic proteins, presumably ZO-1, ZO-2, and ZO-3, in localizing occludin in tight junction fibrils. Such a scaffolding and cytoskeletal coupling function for ZO MAGUKs is analogous to that of other members of the MAGUK family.

Determinants of biliary secretion in isolated perfused skate liver

1982 ◽  
Vol 242 (4) ◽  
pp. G319-G325 ◽  
Author(s):  
J. S. Reed ◽  
N. D. Smith ◽  
J. L. Boyer
Keyword(s):  
Tight Junctions ◽  
Bile Flow ◽  
Perfusion Pressure ◽  
Freeze Fracture ◽  
Biliary Tree ◽  
Solute Diffusion ◽  
Electron Microscopic ◽  
Bile Formation ◽  
Ionic Lanthanum ◽  
Microscopic Studies

In the isolated perfused liver of the little skate, Raja erinacea, bile flow averaged 5.07 +/- 0.58 (mean +/- SE) microliters.h-1.g liver-1 in 21 experiments at a perfusion pressure of 5.0 cm Ringer compared to 3.79 +/- 0.32 in 38 experiments at 2.5 cm (P less than 0.05). [14C]inulin readily entered skate bile. Bile-to-plasma [14C]inulin ratios corrected for delay in transit time, averaged 0.46 +/- 0.07 at 1 h and rose to 0.74 +/- 0.06 by 4 h, although bile flow remained constant. In experiments in which [14C]inulin reached equilibrium between bile and plasma, the bile-to-plasma ratio conformed to the theoretical relationship between bile flow, solvent drag, and inert solute diffusion predicted at extremely low bile flows, but demonstrated that the skate biliary tree is more permeable to inulin than that of the rat. Electron microscopic studies demonstrated that ionic lanthanum could traverse the tight junctions. However, freeze-fracture studies of junction structure did not differ qualitatively from similar studies in the rat. Partial dependence of bile flow on perfusion pressure, high bile-to-plasma inulin ratios, and permeability of the canalicular tight junctions to ionic lanthanum all suggest that the paracellular pathway may be an important component of bile formation in the skate.

scholarly journals Keratinocyte junctions and the epidermal barrier

2002 ◽  
Vol 156 (6) ◽  
pp. 947-949 ◽  
Author(s):  
Gianfranco Bazzoni ◽  
Elisabetta Dejana
Keyword(s):  
Tight Junctions ◽  
Intercellular Junctions ◽  
Permeability Barrier ◽  
Epidermal Barrier

Although intercellular junctions are known to be the major regulators of permeability of simple epithelia, they had not been thought to be important in regulating the permeability of stratified mammalian epithelia. Furuse et al. (2002)(this issue) demonstrate that functional tight junctions may indeed be a necessary part of the permeability barrier of the skin.

scholarly journals A permeability barrier surrounds taste buds in lingual epithelia

2015 ◽  
Vol 308 (1) ◽  
pp. C21-C32 ◽  
Author(s):  
Robin Dando ◽  
Elizabeth Pereira ◽  
Mani Kurian ◽  
Rene Barro-Soria ◽  
Nirupa Chaudhari ◽  
...  
Keyword(s):  
Tight Junctions ◽  
Basic Research ◽  
Taste Buds ◽  
Cell Junctions ◽  
Sensory Cells ◽  
Permeability Barrier ◽  
Entire Body ◽  
Lingual Epithelium ◽  
Tissue Samples ◽  
Extracellular Matrix Components

Epithelial tissues are characterized by specialized cell-cell junctions, typically localized to the apical regions of cells. These junctions are formed by interacting membrane proteins and by cytoskeletal and extracellular matrix components. Within the lingual epithelium, tight junctions join the apical tips of the gustatory sensory cells in taste buds. These junctions constitute a selective barrier that limits penetration of chemosensory stimuli into taste buds (Michlig et al. J Comp Neurol 502: 1003–1011, 2007). We tested the ability of chemical compounds to permeate into sensory end organs in the lingual epithelium. Our findings reveal a robust barrier that surrounds the entire body of taste buds, not limited to the apical tight junctions. This barrier prevents penetration of many, but not all, compounds, whether they are applied topically, injected into the parenchyma of the tongue, or circulating in the blood supply, into taste buds. Enzymatic treatments indicate that this barrier likely includes glycosaminoglycans, as it was disrupted by chondroitinase but, less effectively, by proteases. The barrier surrounding taste buds could also be disrupted by brief treatment of lingual tissue samples with DMSO. Brief exposure of lingual slices to DMSO did not affect the ability of taste buds within the slice to respond to chemical stimulation. The existence of a highly impermeable barrier surrounding taste buds and methods to break through this barrier may be relevant to basic research and to clinical treatments of taste.

Extracellular Ca2+ directly regulates tight junctional permeability in the human cervical cell line CaSki

1997 ◽  
Vol 272 (2) ◽  
pp. C511-C524 ◽  
Author(s):  
G. I. Gorodeski ◽  
W. Jin ◽  
U. Hopfer
Keyword(s):  
Tight Junctions ◽  
Calcium Concentration ◽  
Calcium Influx ◽  
Partial Agonist ◽  
Electrical Conductance ◽  
Cytosolic Calcium ◽  
Extracellular Calcium ◽  
Maximal Effect ◽  
Response Curves ◽  
Junctional Permeability

Lowering extracellular calcium concentration ([Ca2+]o) increases acutely and reversibly the transepithelial electrical conductance (G(TE)) and the epithelial permeability to pyranine (Ppyr) across CaSki cultures. Effects were already observed after lowering calcium from 1.2 to 1.0 mM and were maximal at 0.1 mM. The dose-response curves were sigmoidal (calcium concentration that produces half-maximal effect = 0.3 mM), and the time courses indicated simple exponential trends (time constants of 4-5 min). The effect of calcium was not mediated by mobilization of cytosolic calcium or altering calcium influx, and manganese was found to be a partial agonist to [Ca2+]o. The effects of [Ca2+]o, on permeability were additive to those of hypertonic conditions, indicating that calcium modulates junctional permeability. The experimental data were fitted to theoretical models that relate changes in G(TE) to the probability of assembled/disassembled tight junctions. The results suggest that calcium interacts directly and cooperatively at extracellular sites with junctional elements that are arranged in parallel, and it shifts the probability state of the junctions from "open" to "closed" state. Changes in extracellular calcium may affect the permeability of tight junctions of the cervical epithelium and may play a role in regulating production of cervical mucus.

Modulation of the junctional integrity by low or high concentrations of cytochalasin B and dihydrocytochalasin B in associated with distinct changes in F-actin and ZO-1

1996 ◽  
Vol 16 (4) ◽  
pp. 313-326 ◽  
Author(s):  
Pia Nybom ◽  
Karl-Eric Magnusson
Keyword(s):  
Tight Junction ◽  
Cytochalasin B ◽  
Freeze Fracture ◽  
Permeability Barrier ◽  
Electrical Measurements ◽  
Specific Effects ◽  
Actin Structure ◽  
Junctional Permeability ◽  
Freeze Etching ◽  
High Concentrations

In a study of Necturus gallbladder epithelium Benzel et al. (Benzel et al., 1980) found that low (0.2–1.2 μM) and higher concentrations (1.5 μM and more) of cytochalasin B (CB) caused an increase and decrease in the transepithelial electrical resistance (TER), respectively. Moreover, there were slight changes in the height and complexicity of tight junction (TJ) strands, as visualized by freeze-fracture and freeze-etching. To elucidate the mechanisms of these findings, we first demonstrated that the effect is also present in monolayers of Madin-Darby Canine Kidney strain I (MDCK-I) cells. Thus, a low concentration (0.1 ng/ml) cytochalasin B (CB) strengthened the permeability barrier, as evidenced quantitatively by increases in TER on transepithelial electrical measurements. Furthermore, indirect immunofluorescence and confocal microscopy demonstrated that this effect was paralleled with an accumulation of F-actin and the tight junction marker protein, ZO-1, at the level of TJ. Equimolar concentrations of dihydrocytochalasin B (dhCB), on the other hand, did not lead to a tightening of the epithelium. Confirming previous studies, there was a general decrease in epithelial resistance after treatment with high concentrations (1 μg/ml) of CB and dhCB, which was accompanied by distinct changes in the F-actin network and distribution of ZO-1. We speculate that the divergent effects of CB and dhCB on the F-actin and ZO-1 organization might be due to specific effects on the transport of monosaccharides across the plasma membrane, or that CB and dhCB in distinct ways involve the turnover of phosphatidylinositols in the membrane, thereby modulating junctional permeability and F-actin structure.

scholarly journals Definitive Evidence for the existence of tight junctions in invertebrates

1980 ◽  
Vol 86 (3) ◽  
pp. 765-774 ◽  
Author(s):  
NJ Lane ◽  
HJ Chandler
Keyword(s):  
Tight Junctions ◽  
Freeze Fracture ◽  
Permeability Barrier ◽  
Thin Sections ◽  
Definitive Evidence ◽  
Common Precursor ◽  
En Face ◽  
Spider Central Nervous System ◽  
Exogenous Compounds ◽  
Colloidal Lanthanum

Extensive and unequivocal tight junctions are here reported between the lateral borders of the cellular layer that circumscribes the arachnid (spider) central nervous system. This account details the features of these structures, which form a beltlike reticulum that is more complex than the simple linear tight junctions hitherto found in invertebrate tissues and which bear many of the characteristics of vertebrate zonulae occludentes. We also provide evidence that these junctions form the basis of a permeability barrier to exogenous compounds. In thin sections, the tight junctions are identifiable as punctate points of membrane apposition; they are seen to exclude the stain and appear as election- lucent moniliform strands along the lines of membrane fusion in en face views of uranyl-calcium-treated tissues. In freeze-fracture replicas, the regions of close membrane apposition exhibit P-face (PF) ridges and complementary E-face (EF) furrows that are coincident across face transitions, although slightly offset with respect to one another. The free inward diffusion of both ionic and colloidal lanthanum is inhibited by these punctate tight junctions so that they appear to form the basis of a circumferential blood-brain barrier. These results support the contention that tight junctions exist in the tissues of the invertebrata in spite of earlier suggestions that (a) they are unique to vertebrates and (b) septate junctions are the equivalent invertebrate occluding structure. The component tight junctional 8- to 10-nm-particulate PF ridges are intimately intercalated with, but clearly distinct from, inverted gap junctions possessing the 13-nm EF particles typical of arthropods. Hence, no confusion can occur as to which particles belong to each of the two junctional types, as commonly happens with vertebrate tissues, especially in the analysis of developing junctions. Indeed, their coexistance in this way supports the idea, over which there has been some controversy, that the intramembrane particles making up these two junctional types must be quite distinct entities rather than products of a common precursor.

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