The Experts below are selected from a list of 714 Experts worldwide ranked by ideXlab platform
Mikio Furuse - One of the best experts on this subject based on the ideXlab platform.
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Occludin and Tricellulin facilitate formation of anastomosing tight-junction strand network to improve barrier function.
Molecular biology of the cell, 2021Co-Authors: Akira C. Saito, Mikio Furuse, Tetsuhisa Otani, Tomohito Higashi, Yugo Fukazawa, Masashi Tauchi, Atsuko Y Higashi, Hideki ChibaAbstract:Tight junctions (TJs) are composed of a claudin-based anastomosing network of TJ strands, at which plasma membranes of adjacent epithelial cells are closely attached to regulate the paracellular permeability. Although the TJ proteins occludin and Tricellulin have been known to be incorporated in the TJ strand network, their molecular functions remain unknown. Here, we established Tricellulin/occludin-double knockout (dKO) MDCK II cells using a genome editing technique, and evaluated the structure and barrier function of these cells. In freeze-fracture replica electron microscopy, the TJ strands of Tricellulin/occludin-dKO cells had fewer branches and were less anastomosed compared with the controls. The paracellular permeability of ions and small tracers was increased in the dKO cells. A single KO of Tricellulin or occludin had limited effects on the morphology and permeability of TJs. Mathematical simulation using a simplified TJ strand network model predicted that reduced cross-links in TJ strands lead to increased permeability of ions and small macromolecules. Furthermore, overexpression of occludin increased the complexity of TJ strand network and strengthened barrier function. Taken together, our data suggest that Tricellulin and occludin mediate the formation and/or stabilization of TJ strand branching points, and contribute to the maintenance of epithelial barrier integrity. [Media: see text].
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Angulin-1 seals tricellular contacts independently of Tricellulin and claudins
2020Co-Authors: Taichi Sugawara, Tetsuhisa Otani, Kyoko Furuse, Mikio FuruseAbstract:Abstract Tricellular tight junctions (tTJs) are specialized tight junctions (TJs) that seal the intercellular space at tricellular contacts (TCs), where the vertices of three epithelial cells meet. Tricellulin and angulin family membrane proteins are known constituents of tTJs, but the molecular mechanism of tTJ formation remains elusive. Here, we investigated the roles of angulin-1 and Tricellulin in tTJ formation in MDCK II cells by genome editing. Angulin-1-deficient cells lost the plasma membrane contact at TCs with impaired epithelial barrier function. The COOH-terminus of angulin-1 bound to the TJ scaffold protein ZO-1 and disruption of their interaction influenced the localization of claudins at TCs, but not the tricellular sealing. Strikingly, the plasma membrane contact at TCs was formed in Tricellulin- or claudin-deficient cells. These findings demonstrate that angulin-1 is responsible for the plasma membrane seal at TCs independently of Tricellulin and claudins.
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RESEARCH ARTICLE Deafness
2016Co-Authors: Shinichiro Kitajiri, Hiroyuki Sasaki, Mikio Furuse, Tatsuya Katsuno, Juichi Ito, Sachiko TsukitaAbstract:in occludin-deficient mice with dislocation of Tricellulin and progressive apoptosis of the hair cell
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RESEARCH ARTICLE Deficiency of Angulin-2/ILDR1, a Tricellular Tight Junction-Associated Membrane Protein, Causes Deafness with Cochlear Hair Cell Degeneration in Mice
2016Co-Authors: Tomohito Higashi, Shinichiro Kitajiri, Tatsuya Katsuno, Mikio FuruseAbstract:Tricellular tight junctions seal the extracellular spaces of tricellular contacts, where the verti-ces of three epithelial cells meet, and are required for the establishment of a strong barrier function of the epithelial cellular sheet. Angulins and Tricellulin are known as specific protein components of tricellular tight junctions, where angulins recruit Tricellulin. Mutations in the genes encoding angulin-2/ILDR1 and Tricellulin have been reported to cause human heredi-tary deafness DFNB42 and DFNB49, respectively. To investigate the pathogenesis of DFNB42, we analyzed mice with a targeted disruption of Ildr1, which encodes angulin-2/ ILDR1. Ildr1 null mice exhibited profound deafness. Hair cells in the cochlea of Ildr1 null mice develop normally, but begin to degenerate by two weeks after birth. Tricellulin localiza-tion at tricellular contacts of the organ of Corti in the cochlea was retained in Ildr1 null mice, but its distribution along the depth of tricellular contacts was affected. Interestingly, compen-satory tricellular contact localization of angulin-1/LSR was observed in the organ of Corti in Ildr1 null mice although it was hardly detected in the organ of Corti in wild-type mice. The onset of hair cell degeneration in Ildr1 null mice was earlier than that in the reported Tricmu
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Deficiency of Angulin-2/ILDR1, a Tricellular Tight Junction-Associated Membrane Protein, Causes Deafness with Cochlear Hair Cell Degeneration in Mice
PloS one, 2015Co-Authors: Tomohito Higashi, Shinichiro Kitajiri, Tatsuya Katsuno, Mikio FuruseAbstract:Tricellular tight junctions seal the extracellular spaces of tricellular contacts, where the vertices of three epithelial cells meet, and are required for the establishment of a strong barrier function of the epithelial cellular sheet. Angulins and Tricellulin are known as specific protein components of tricellular tight junctions, where angulins recruit Tricellulin. Mutations in the genes encoding angulin-2/ILDR1 and Tricellulin have been reported to cause human hereditary deafness DFNB42 and DFNB49, respectively. To investigate the pathogenesis of DFNB42, we analyzed mice with a targeted disruption of Ildr1, which encodes angulin-2/ILDR1. Ildr1 null mice exhibited profound deafness. Hair cells in the cochlea of Ildr1 null mice develop normally, but begin to degenerate by two weeks after birth. Tricellulin localization at tricellular contacts of the organ of Corti in the cochlea was retained in Ildr1 null mice, but its distribution along the depth of tricellular contacts was affected. Interestingly, compensatory tricellular contact localization of angulin-1/LSR was observed in the organ of Corti in Ildr1 null mice although it was hardly detected in the organ of Corti in wild-type mice. The onset of hair cell degeneration in Ildr1 null mice was earlier than that in the reported Tric mutant mice, which mimic one of the Tricellulin mutations in DFNB49 deafness. These results indicate that the angulin-2/ILDR1 deficiency causes the postnatal degenerative loss of hair cells in the cochlea, leading to human deafness DFNB42. Our data also suggest that angulin family proteins have distinct functions in addition to their common roles of Tricellulin recruitment and that the function of angulin-2/ILDR1 for hearing cannot be substituted by angulin-1/LSR.
Michael Fromm - One of the best experts on this subject based on the ideXlab platform.
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Leptin Downregulates Angulin-1 in Active Crohn's Disease via STAT3.
International journal of molecular sciences, 2020Co-Authors: Christian Bojarski, Michael Fromm, F Branchi, Susanne M. KrugAbstract:Crohn's disease (CD) has an altered intestinal barrier function, yet the underlying mechanisms remain to be disclosed. The tricellular tight junction protein Tricellulin is involved in the maintenance of the paracellular macromolecule barrier and features an unchanged expression level in CD but a shifted localization. As angulins are known to regulate the localization of Tricellulin, we hypothesized the involvement of angulins in CD. Using human biopsies, we found angulin-1 was downregulated in active CD compared with both controls and CD in remission. In T84 and Caco-2 monolayers, leptin, a cytokine secreted by fat tissue and affected in CD, decreased angulin-1 expression. This effect was completely blocked by STAT3 inhibitors, Stattic and WP1066, but only partially by JAK2 inhibitor AG490. The effect of leptin was also seen at a functional level as we observed in Caco-2 cells an increased permeability for FITC-dextran 4 kDa indicating an impaired barrier against macromolecule uptake. In conclusion, we were able to show that in active CD angulin-1 expression is downregulated, which leads to increased macromolecule permeability and is inducible by leptin via STAT3. This suggests that angulin-1 and leptin secretion are potential targets for intervention in CD to restore the impaired intestinal barrier.
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Tricellulin Effect on Paracellular Water Transport
International journal of molecular sciences, 2019Co-Authors: Carlos Ayala-torres, Susanne M. Krug, Jörg D. Schulzke, Rita Rosenthal, Michael FrommAbstract:In epithelia, large amounts of water pass by transcellular and paracellular pathways, driven by the osmotic gradient built up by the movement of solutes. The transcellular pathway has been molecularly characterized by the discovery of aquaporin membrane channels. Unlike this, the existence of a paracellular pathway for water through the tight junctions (TJ) was discussed controversially for many years until two molecular components of paracellular water transport, claudin-2 and claudin-15, were identified. A main protein of the tricellular TJ (tTJ), Tricellulin, was shown to be downregulated in ulcerative colitis leading to increased permeability to macromolecules. Whether or not Tricellulin also regulates water transport is unknown yet. To this end, an epithelial cell line featuring properties of a tight epithelium, Madin-Darby canine kidney cells clone 7 (MDCK C7), was stably transfected with small hairpin RNA (shRNA) targeting Tricellulin, a protein of the tTJ essential for the barrier against passage of solutes up to 10 kDa. Water flux was induced by osmotic gradients using mannitol or 4 and 40 kDa-dextran. Water flux in Tricellulin knockdown (KD) cells was higher compared to that of vector controls, indicating a direct role of Tricellulin in regulating water permeability in a tight epithelial cell line. We conclude that Tricellulin increases water permeability at reduced expression.
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Angubindin-1, a novel paracellular absorption enhancer acting at the tricellular tight junction
Journal of controlled release : official journal of the Controlled Release Society, 2017Co-Authors: Susanne M. Krug, Michael Fromm, Tomohiro Hayaishi, Daisuke Iguchi, Akihiro Watari, Azusa Takahashi, Masahiro Nagahama, Hiroyuki Takeda, Yoshiaki Okada, Tatsuya SawasakiAbstract:A limiting barrier for mucosal absorption of drugs is the tight junction (TJ). TJs exist between two adjacent cells (bicellular TJ, bTJ) and at the sites where three cells meet (tricellular TJ, tTJ). We present a novel approach which employs a physiologically regulated pathway for the passage of large molecules through the tTJ. Main barrier-relevant tTJ proteins are Tricellulin and angulin-1 to -3. We developed an angulin binder from Clostridium perfringens iota-toxin (Ib) whose receptor is angulin-1. An Ib fragment corresponding to amino acids 421–664 (Ib421-664) of iota-toxin proved to bind in cells expressing angulin-1 and -3, but not angulin-2. This binding led to removal of angulin-1 and Tricellulin from the tTJ which enhanced the permeation of macromolecular solutes. Ib421-664 enhanced intestinal absorption in rats and mice. Our findings indicate that Ib421-664, which we designate angubindin-1, is a modulator of the tTJ barrier and that modulation of that barrier qualifies for a new strategy of developing a mucosal absorption enhancer.
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Architectural and functional alterations of the small intestinal mucosa in classical Whipple's disease.
Mucosal immunology, 2017Co-Authors: H. J. Epple, Susanne M. Krug, Anja Fromm, Julian Friebel, Verena Moos, Hanno Troeger, Kristina Allers, Katina Schinnerling, Britta Siegmund, Michael FrommAbstract:Classical Whipple's disease (CWD) affects the gastrointestinal tract and rather elicits regulatory than inflammatory immune reactions. Mechanisms of malabsorption, diarrhea, and systemic immune activation are unknown. We here analyzed mucosal architecture, barrier function, and immune activation as potential diarrheal trigger in specimens from 52 CWD patients. Our data demonstrate villus atrophy and crypt hyperplasia associated with epithelial apoptosis and reduced alkaline phosphatase expression in the duodenum of CWD patients. Electrophysiological and flux experiments revealed increased duodenal permeability to small solutes and macromolecules. Duodenal architecture and permeability ameliorated upon antibiotic treatment. Structural correlates for these alterations were concordant changes of membranous claudin-1, claudin-2, claudin-3, and Tricellulin expression. Tumor necrosis factor-α and interleukin-13 were identified as probable mediators of epithelial apoptosis, and altered tight junction expression. Increased serum markers of microbial translocation and their decline following treatment corroborated the biological significance of the mucosal barrier defect. Hence, mucosal immune responses in CWD elicit barrier dysfunction. Diarrhea is caused by loss of absorptive capacity and leak flux of ions and water. Downregulation of Tricellulin causes increased permeability to macromolecules and subsequent microbial translocation contributes to systemic inflammation. Thus, therapeutic strategies to reconstitute the mucosal barrier and control inflammation could assist symptomatic control of CWD.
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Sodium caprate as an enhancer of macromolecule permeation across tricellular tight junctions of intestinal cells
Biomaterials, 2012Co-Authors: Susanne M. Krug, Michael Fromm, Maren Amasheh, Isabel Dittmann, Ilya Christoffel, Salah AmashehAbstract:Sodium caprate is a promising candidate for inducing drug absorption enhancement. The mechanism of that uptake-enhancing effect is not fully understood so far. We investigated how caprate acts in an established human intestinal cell line, HT-29/B6, on the transient opening of transcellular (across the cell membranes) and paracellular (across the tight junction) pathways. Sodium caprate (10 mm) caused a rapid and reversible decrease of transepithelial resistance which is based, as measured by two-path impedance spectroscopy, exclusively on resistance changes of the paracellular pathway. Measurements of paracellular marker fluxes revealed an increased permeability for fluorescein (330 Da) and FITC-dextran (4 and 10 kDa), indicating an opening of the paracellular barrier. Confocal microscopy revealed a marked reduction of Tricellulin in tricellular tight junctions and of claudin-5 in bicellular tight junctions. This was not due to altered protein expression, as occludin, claudins or Tricellulin were not significantly changed in Western blots. Visualization of the translocation site of the cell membrane-impermeable marker molecule sulpho-NHS-SS-biotin (607 Da) indicated the tricellular tight junction to be the predominant pathway. We suggest that caprate's known enhancing effect on intestinal drug uptake is based on increased permeability in tricellular cell contacts, mediated by reversible removal of Tricellulin from the tricellular tight junction.
Susanne M. Krug - One of the best experts on this subject based on the ideXlab platform.
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Leptin Downregulates Angulin-1 in Active Crohn's Disease via STAT3.
International journal of molecular sciences, 2020Co-Authors: Christian Bojarski, Michael Fromm, F Branchi, Susanne M. KrugAbstract:Crohn's disease (CD) has an altered intestinal barrier function, yet the underlying mechanisms remain to be disclosed. The tricellular tight junction protein Tricellulin is involved in the maintenance of the paracellular macromolecule barrier and features an unchanged expression level in CD but a shifted localization. As angulins are known to regulate the localization of Tricellulin, we hypothesized the involvement of angulins in CD. Using human biopsies, we found angulin-1 was downregulated in active CD compared with both controls and CD in remission. In T84 and Caco-2 monolayers, leptin, a cytokine secreted by fat tissue and affected in CD, decreased angulin-1 expression. This effect was completely blocked by STAT3 inhibitors, Stattic and WP1066, but only partially by JAK2 inhibitor AG490. The effect of leptin was also seen at a functional level as we observed in Caco-2 cells an increased permeability for FITC-dextran 4 kDa indicating an impaired barrier against macromolecule uptake. In conclusion, we were able to show that in active CD angulin-1 expression is downregulated, which leads to increased macromolecule permeability and is inducible by leptin via STAT3. This suggests that angulin-1 and leptin secretion are potential targets for intervention in CD to restore the impaired intestinal barrier.
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Tricellulin Effect on Paracellular Water Transport
International journal of molecular sciences, 2019Co-Authors: Carlos Ayala-torres, Susanne M. Krug, Jörg D. Schulzke, Rita Rosenthal, Michael FrommAbstract:In epithelia, large amounts of water pass by transcellular and paracellular pathways, driven by the osmotic gradient built up by the movement of solutes. The transcellular pathway has been molecularly characterized by the discovery of aquaporin membrane channels. Unlike this, the existence of a paracellular pathway for water through the tight junctions (TJ) was discussed controversially for many years until two molecular components of paracellular water transport, claudin-2 and claudin-15, were identified. A main protein of the tricellular TJ (tTJ), Tricellulin, was shown to be downregulated in ulcerative colitis leading to increased permeability to macromolecules. Whether or not Tricellulin also regulates water transport is unknown yet. To this end, an epithelial cell line featuring properties of a tight epithelium, Madin-Darby canine kidney cells clone 7 (MDCK C7), was stably transfected with small hairpin RNA (shRNA) targeting Tricellulin, a protein of the tTJ essential for the barrier against passage of solutes up to 10 kDa. Water flux was induced by osmotic gradients using mannitol or 4 and 40 kDa-dextran. Water flux in Tricellulin knockdown (KD) cells was higher compared to that of vector controls, indicating a direct role of Tricellulin in regulating water permeability in a tight epithelial cell line. We conclude that Tricellulin increases water permeability at reduced expression.
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Crystal structure of the Tricellulin C-terminal coiled-coil domain reveals a unique mode of dimerization.
Annals of the New York Academy of Sciences, 2017Co-Authors: Anja Schuetz, Susanne M. Krug, Veselina Radusheva, Udo HeinemannAbstract:Tricellulin is a tight junction protein localized to tricellular contacts in many epithelial tissues, where it is required for full barrier control. Here, we present crystal structures of the Tricellulin C-terminal coiled-coil domain, revealing a potential dimeric arrangement. By combining structural, biochemical, functional, and mutation analyses, we gain insight into the mode of Tricellulin oligomerization and suggest a model where dimerization of its cytoplasmic C-terminus may play an auxiliary role in stabilizing homophilic and potentially also heterophilic cis-interactions within tight junctions.
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Trictide, a Tricellulin-derived peptide to overcome cellular barriers.
Annals of the New York Academy of Sciences, 2017Co-Authors: Jimmi Cording, Susanne M. Krug, Basak Arslan, Christian Staat, Sophie Dithmer, Anneliese Krüger, Philipp Berndt, Ramona Günther, Lars Winkler, Ingolf E. BlasigAbstract:The majority of tight junction (TJ) proteins restrict the paracellular permeation of solutes via their extracellular loops (ECLs). Tricellulin tightens tricellular TJs (tTJs) and regulates bicellular TJ (bTJ) proteins. We demonstrate that the addition of recombinantly produced extracellular loop 2 (ECL2) of Tricellulin opens cellular barriers. The peptidomimetic trictide, a synthetic peptide derived from Tricellulin ECL2, increases the passage of ions, as well as of small and larger molecules up to 10 kDa, between 16 and 30 h after application to human epithelial colorectal adenocarcinoma cell line 2. Tricellulin and lipolysis-stimulated lipoprotein receptor relocate from tTJs toward bTJs, while the TJ proteins claudin-1 and occludin redistribute from bTJs to the cytosol. Analyzing the opening of the tricellular sealing tube by the peptidomimetic using super-resolution stimulated-emission depletion microscopy revealed a Tricellulin-free area at the tricellular region. Cis-interactions (as measured by fluorescence resonance energy transfer) of Tricellulin–Tricellulin (tTJs), Tricellulin–claudin-1, Tricellulin–marvelD3, and occludin–occludin (bTJs) were strongly affected by trictide treatment. Circular dichroism spectroscopy and molecular modeling suggest that trictide adopts a β-sheet structure, resulting in a peculiar interaction surface for its binding to Tricellulin. In conclusion, trictide is a novel and promising tool for overcoming cellular barriers at bTJs and tTJs with the potential to transiently improve drug delivery.
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Contribution of the tricellular tight junction to paracellular permeability in leaky and tight epithelia.
Annals of the New York Academy of Sciences, 2017Co-Authors: Susanne M. KrugAbstract:The tricellular tight junction (tTJ) is a potential weak point of the paracellular barrier. For solving the proportional contribution of the tTJ, ion conductances and macromolecule permeabilities were analyzed in cell lines of different leakiness. MDCK II, Caco-2, and HT-29/B6 cells were subjected to two-path impedance spectroscopy and morphological analyses in order to calculate the contribution of the tTJ to paracellular and total ion conductivity. The contribution to macromolecule permeability was evaluated by Tricellulin overexpression or knockdown. Tricellulin-dependent macromolecule passage was comparably regulated in leaky and tight epithelia, but relative and absolute ion permeabilities of the tTJs were different. Assuming a minimal (50 pS) and maximal (146 pS) conductivity per single tTJ, the possible range of contribution of the tTJ to paracellular ion conductance amounted to only 0.3-1.1% in the leaky cell line MDCK II, but 3-25% in the moderately tight cell line Caco-2, and not less than 29% in the tight cell line HT-29/B6. In these cells, this resulted in a contribution to total epithelial conductance of 9-32%. In conclusion, in leaky epithelia the bicellular TJ accounts for nearly the entire paracellular ion conductance, whereas in tight epithelia the low bicellular TJ conductance has large impact on the tTJ.
Takashi Kojima - One of the best experts on this subject based on the ideXlab platform.
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ASPP2 suppression promotes malignancy via LSR and YAP in human endometrial cancer
Histochemistry and Cell Biology, 2020Co-Authors: Takumi Konno, Takayuki Kohno, Tadahi Okada, Hiroshi Shimada, Seiro Satohisa, Shin Kikuchi, Tsuyoshi Saito, Takashi KojimaAbstract:Apoptosis-stimulating p53 protein 2 (ASPP2) is an apoptosis inducer that acts via binding with p53 and epithelial polarity molecule PAR3. Lipolysis-stimulated lipoprotein receptor (LSR) is an important molecule at tricellular contacts, and loss of LSR promotes cell migration and invasion via Yes-associated protein (YAP) in human endometrial cancer cells. In the present study, to find how ASPP2 suppression promotes malignancy in human endometrial cancer, we investigated its mechanisms including the relationship with LSR. In endometriosis and endometrial cancers (G1 and G2), ASPP2 was observed as well as PAR3 and LSR in the subapical region. ASPP2 decreased in G3 endometrial cancer compared to G1. In human endometrial cancer cell line Sawano, ASPP2 was colocalized with LSR and Tricellulin at tricellular contacts and binding to PAR3, LSR, and Tricellulin in the confluent state. ASPP2 suppression promoted cell migration and invasion, decreased LSR expression, and induced expression of phosphorylated YAP, claudin-1, -4, and -7 as effectively as the loss of LSR. Knockdown of YAP prevented the upregulation of pYAP, cell migration and invasion induced by the ASPP2 suppression. Treatment with a specific antibody against ASPP2 downregulated ASPP2 and LSR, affected F-actin at tricellular contacts, upregulated expression of pYAP and claudin-1, and induced cell migration and invasion via YAP. In normal human endometrial epithelial cells, ASPP2 was in part colocalized with LSR at tricellular contacts and knockdown of ASPP2 or LSR induced expression of claudin-1 and claudin-4. ASPP2 suppression promoted cell invasion and migration via LSR and YAP in human endometrial cancer cells.
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Localization of Tricellular Tight Junction Molecule LSR at Midbody and Centrosome During Cytokinesis in Human Epithelial Cells.
The journal of histochemistry and cytochemistry : official journal of the Histochemistry Society, 2019Co-Authors: Takumi Konno, Ken-ichi Takano, Takayuki Kohno, Hiroshi Shimada, Seiro Satohisa, Shin Kikuchi, Tsuyoshi Saito, Takashi KojimaAbstract:Epithelial integrity and barrier function are maintained during cytokinesis in vertebrate epithelial tissues. The changes in localization and the roles of tricellular tight junction molecule lipolysis-stimulated lipoprotein receptor (LSR) during cytokinesis are not well known, although new tricellular tight junctions form at the flank of the midbody during cytokinesis. In this study, we investigated the changes in localization and the role of LSR at the midbody and centrosome during cytokinesis using human endometrial carcinoma cell line Sawano, comparing the tricellular tight junction molecule Tricellulin; bicellular tight junction molecules occludin, claudin-7, zonula occludens-1, and cingulin; and the epithelial polarized related molecules apoptosis-stimulating of p53 protein 2, PAR3, and yes-associated protein. During cytokinesis induced by treatment with taxol, the epithelial barrier was maintained and the tricellular tight junction molecules LSR and Tricellulin were concentrated at the flank of the acetylated tubulin-positive midbody and in γ-tubulin-positive centrosomes with the dynein adaptor Hook2, whereas the other molecules were localized there as well. All the molecules disappeared by knockdown using small interfering RNAs. Furthermore, by the knockdown of Hook2, the epithelial barrier was maintained and most of the molecules disappeared from the centrosome. These findings suggest that LSR may play crucial roles not only in barrier function but also in cytokinesis.
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Role of Tricellular Tight Junction Protein Lipolysis-Stimulated Lipoprotein Receptor (LSR) in Cancer Cells
International Journal of Molecular Sciences, 2019Co-Authors: Takayuki Kohno, Takumi Konno, Takashi KojimaAbstract:Maintaining a robust epithelial barrier requires the accumulation of tight junction proteins, LSR/angulin-1 and Tricellulin, at the tricellular contacts. Alterations in the localization of these proteins temporarily cause epithelial barrier dysfunction, which is closely associated with not only physiological differentiation but also cancer progression and metastasis. In normal human endometrial tissues, the endometrial cells undergo repeated proliferation and differentiation under physiological conditions. Recent observations have revealed that the localization and expression of LSR/angulin-1 and Tricellulin are altered in a menstrual cycle-dependent manner. Moreover, it has been shown that endometrial cancer progression affects these alterations. This review highlights the differences in the localization and expression of tight junction proteins in normal endometrial cells and endometrial cancers and how they cause functional changes in cells.
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Nuclear localization of Tricellulin promotes the oncogenic property of pancreatic cancer
Scientific reports, 2016Co-Authors: Akira Takasawa, Masaki Murata, Kumi Takasawa, Yusuke Ono, Makoto Osanai, Satoshi Tanaka, Masanori Nojima, Tsuyoshi Kono, Koichi Hirata, Takashi KojimaAbstract:Accumulating evidence has shown that dysregulation of tight junctions (TJs) is involved in tumor development and progression. In this study, we investigated the expression and subcellular distribution of Tricellulin, which constitutes tricellular TJs, using human pancreatic adenocarcinomas. In well-differentiated pancreatic adenocarcinoma tissues, Tricellulin immunostaining was prominent in the cytoplasm and the plasma membrane. In contrast, in poorly differentiated tissues, its immunostaining was predominantly observed in the nuclei and was almost absent in the plasma membrane. The distinct immunostaining of Tricellulin successfully distinguished poorly differentiated adenocarcinoma from moderately and well-differentiated adenocarcinomas with high levels of sensitivity and specificity. Nuclear Tricellulin expression significantly correlated with lymph node metastasis, lymphatic invasion and poor survival. In pancreatic cancer cell lines, Tricellulin localization shifted from the membrane to nucleus with decreasing differentiation status. Nuclear localization of Tricellulin promoted cell proliferation and invasiveness possibly in association with MAPK and PKC pathways in pancreatic cancers. Our results provide new insights into the function of Tricellulin, and its nuclear localization may become a new prognostic factor for pancreatic cancers.
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Behavior of Primary Cilia and Tricellular Tight Junction Proteins during Differentiation in Temperature-Sensitive Mouse Cochlear Precursor Hair Cells.
Advances in oto-rhino-laryngology, 2016Co-Authors: Takuya Kakuki, Ken-ichi Takano, Takayuki Kohno, Takashi Kojima, Takafumi Ninomiya, Yakuto Kaneko, Tetsuo HimiAbstract:In the sensory hair cells of the mammalian cochlea, the primary cilia in the planar cell polarity as well as the tight junctions in the epithelial cell polarity and the barrier are important to maintain normal hearing. Temperature-sensitive mouse cochlear precursor hair cells were used to investigate the behavior of primary cilia and tricellular tight junction proteins during the differentiation of sensory hair cells. In undifferentiated cells (incubated at 33°C), many acetylated tubulin-positive primary cilia were observed, and each was accompanied with an x03B3;-tubulin-positive basal body. The primary cilia had a '9 + 0' architecture with nine outer microtubule doublets but lacking a central pair of microtubules. In differentiated cells (incubated at 39°C), acetylated tubulin-positive primary cilia as well as acetylated tubulin-positive cilia-like structures were partially observed on the cell surface. In differentiated cells, the number of primary cilia was markedly reduced compared with undifferentiated cells, and innumerable cilia-like structures with no ciliary pockets were partially observed on the cell surface. In undifferentiated cells, few Tricellulin molecules and lipolysis-stimulated lipoprotein receptors (LSRs) were observed in the cytoplasm. In differentiated cells, many Tricellulin molecules and LSRs were observed on the membranes and within the cytoplasm. Conditional immortalized mouse cochlear precursor hair cells may be useful to investigate the roles of primary cilia and tricellular tight junctions during cellular differentiation and degeneration such as apoptosis.
Hartwig Wolburg - One of the best experts on this subject based on the ideXlab platform.
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redox regulation of cell contacts by Tricellulin and occludin redox sensitive cysteine sites in Tricellulin regulate both tri and bicellular junctions in tissue barriers as shown in hypoxia and ischemia
Antioxidants & Redox Signaling, 2015Co-Authors: Jimmi Cording, Ramona Günther, Lars Winkler, Emilia Vigolo, Christian Tscheik, Isabella Schlattner, Dorothea Lorenz, Reiner F Haseloff, Kai M Schmidtott, Hartwig WolburgAbstract:Abstract Tight junctions (TJs) seal paracellular clefts in epithelia/endothelia and form tissue barriers for proper organ function. TJ-associated marvel proteins (TAMPs; Tricellulin, occludin, marvelD3) are thought to be relevant to regulation. Under normal conditions, Tricellulin tightens tricellular junctions against macromolecules. Traces of Tricellulin occur in bicellular junctions. Aims: As pathological disturbances have not been analyzed, the structure and function of human Tricellulin, including potentially redox-sensitive Cys sites, were investigated under reducing/oxidizing conditions at 3- and 2-cell contacts. Results: Ischemia, hypoxia, and reductants redistributed Tricellulin from 3- to 2-cell contacts. The extracellular loop 2 (ECL2; conserved Cys321, Cys335) trans-oligomerized between three opposing cells. Substitutions of these residues caused bicellular localization. Cys362 in transmembrane domain 4 contributed to bicellular heterophilic cis-interactions along the cell membrane with claudi...
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Redox Regulation of Cell Contacts by Tricellulin and Occludin: Redox-Sensitive Cysteine Sites in Tricellulin Regulate Both Tri- and Bicellular Junctions in Tissue Barriers as Shown in Hypoxia and Ischemia.
Antioxidants & redox signaling, 2015Co-Authors: Jimmi Cording, Ramona Günther, Lars Winkler, Emilia Vigolo, Christian Tscheik, Isabella Schlattner, Dorothea Lorenz, Reiner F Haseloff, Kai M. Schmidt-ott, Hartwig WolburgAbstract:Tight junctions (TJs) seal paracellular clefts in epithelia/endothelia and form tissue barriers for proper organ function. TJ-associated marvel proteins (TAMPs; Tricellulin, occludin, marvelD3) are thought to be relevant to regulation. Under normal conditions, Tricellulin tightens tricellular junctions against macromolecules. Traces of Tricellulin occur in bicellular junctions. As pathological disturbances have not been analyzed, the structure and function of human Tricellulin, including potentially redox-sensitive Cys sites, were investigated under reducing/oxidizing conditions at 3- and 2-cell contacts. Ischemia, hypoxia, and reductants redistributed Tricellulin from 3- to 2-cell contacts. The extracellular loop 2 (ECL2; conserved Cys321, Cys335) trans-oligomerized between three opposing cells. Substitutions of these residues caused bicellular localization. Cys362 in transmembrane domain 4 contributed to bicellular heterophilic cis-interactions along the cell membrane with claudin-1 and marvelD3, while Cys395 in the cytosolic C-terminal tail promoted homophilic tricellullar cis-interactions. The Cys sites included in homo-/heterophilic bi-/tricellular cis-/trans-interactions contributed to cell barrier tightness for small/large molecules. Tricellulin forms TJs via trans- and cis-association in 3-cell contacts, as demonstrated electron and quantified fluorescence microscopically; it tightens 3- and 2-cell contacts. Tricellulin's ECL2 specifically seals 3-cell contacts redox dependently; a structural model is proposed. TAMP ECL2 and claudins' ECL1 share functionally and structurally similar features involved in homo-/heterophilic tightening of cell-cell contacts. Tricellulin is a specific redox sensor and sealing element at 3-cell contacts and may compensate as a redox mediator for occludin loss at 2-cell contacts in vivo and in vitro. Molecular interaction mechanisms were proposed that contribute to Tricellulin's function. In conclusion, Tricellulin is a junctional redox regulator for ischemia-related alterations.
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transmembrane proteins of the tight junctions at the blood brain barrier structural and functional aspects
Seminars in Cell & Developmental Biology, 2015Co-Authors: Reiner F Haseloff, Lars Winkler, Sophie Dithmer, Hartwig Wolburg, Ingolf E. BlasigAbstract:Abstract The blood–brain barrier (BBB) is formed by microvascular endothelial cells sealed by tetraspanning tight junction (TJ) proteins, such as claudins and TAMPs (TJ-associated marvel proteins, occludin and Tricellulin). Claudins are the major components of the TJs. At the BBB, claudin-5 dominates the TJs by preventing the paracellular permeation of small molecules. On the other hand, TAMPs regulate the structure and function of the TJs; Tricellulin may tighten the barrier for large molecules. This review aims at integrating and summarizing the most relevant and recent work on how the BBB is influenced by claudin-1, -3, -5, -12 and the TAMPs occludin and Tricellulin, all of which are four-transmembrane TJ proteins. The exact functions of claudin-1, -3, -12 and TAMPs at this barrier still need to be elucidated.
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in tight junctions claudins regulate the interactions between occludin Tricellulin and marveld3 which inversely modulate claudin oligomerization
Journal of Cell Science, 2013Co-Authors: Jimmi Cording, Julie K. Westphal, Christian Tscheik, Hartwig Wolburg, Susanne Milatz, Dorothee Günzel, Johanna Berg, Nadja Kading, Christian Bellmann, Jörg PiontekAbstract:Tight junctions seal the paracellular cleft of epithelia and endothelia, form vital barriers between tissue compartments and consist of tight-junction-associated marvel proteins (TAMPs) and claudins. The function of TAMPs and the interaction with claudins are not understood. We therefore investigated the binding between the TAMPs occludin, Tricellulin, and marvelD3 and their interaction with claudins in living tight-junction-free human embryonic kidney-293 cells. In contrast to claudins and occludin, Tricellulin and marvelD3 showed no enrichment at cell-cell contacts indicating lack of homophilic trans-interaction between two opposing cell membranes. However, occludin, marvelD3 and Tricellulin exhibited homophilic cis-interactions, along one plasma membrane, as measured by fluorescence resonance energy transfer. MarvelD3 also cis-interacted with occludin and Tricellulin heterophilically. Classic claudins, such as claudin-1 to -5 may show cis-oligomerization with TAMPs, whereas the non-classic claudin-11 did not. Claudin-1 and -5 improved enrichment of occludin and Tricellulin at cell-cell contacts. The low mobile claudin-1 reduced the membrane mobility of the highly mobile occludin and Tricellulin, as studied by fluorescence recovery after photobleaching. Co-transfection of claudin-1 with TAMPs led to changes of the tight junction strand network of this claudin to a more physiological morphology, depicted by freeze-fracture electron microscopy. The results demonstrate multilateral interactions between the tight junction proteins, in which claudins determine the function of TAMPs and vice versa, and provide deeper insights into the tight junction assembly.
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The different structures containing tight junction proteins in epidermal and other stratified epithelial cells, including squamous cell metaplasia.
European journal of cell biology, 2007Co-Authors: Holger Schlüter, Hartwig Wolburg, Ingrid Moll, Werner W FrankeAbstract:In stratified squamous epithelia constituent proteins of tight junctions (TJs) are not restricted to the zonula occludens-related structures of the uppermost living cell layer such as the stratum granulosum of the epidermis but TJ membrane proteins such as occludin and certain members of the claudin family as well as TJ plaque proteins, notably cingulin and protein ZO-1, have also been identified by immunofluorescence and immunoelectron microscopy in more basal layers where they form special cell-cell-connecting structures such as the "lamellated" and the "sandwich" junctions. In the present study, we describe another TJ protein-containing structure, the very small puncta occludentia ("stud junctions"), as the smallest identifiable TJ-like unit that occurs in most, perhaps all strata. We have also determined the specific distributions of TJ proteins in the cell layers of squamous cell metaplasias of the human bronchial tract. Moreover, we show that the occludin-related tetraspanin protein Tricellulin-alpha connects and seals the membranes of adjacent "three corner" cell structures of the uppermost layer in keratinocytes growing in culture. We hypothesize the possible occurrence of Tricellulin-beta in more basal cell layers of keratinocyte cultures and the general occurrence of different Tricellulin splice forms in stratified epithelia in situ, and discuss the possible functions of TJ proteins in stratified epithelia and tumors derived therefrom.
