The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform
James M. Anderson - One of the best experts on this subject based on the ideXlab platform.
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Newly synthesized Claudins but not occludin are added to the basal side of the tight junction
Molecular Biology of the Cell, 2019Co-Authors: Christina M. Van Itallie, Karin Fredriksson Lidman, Amber Jean Tietgens, James M. AndersonAbstract:A network of Claudin strands creates continuous cell–cell contacts to form the intercellular tight junction barrier; a second protein, occludin, is associated along these strands. The physiological barrier remains stable despite protein turnover, which involves removal and replacement of Claudins both in the steady state and during junction remodeling. Here we use a pulse–block–pulse labeling protocol with fluorescent ligands to label SNAP/CLIP-tags fused to Claudins and occludin to identify their spatial trafficking pathways and kinetics in Madin–Darby canine kidney monolayers. We find that Claudins are first delivered to the lateral membrane and, over time, enter the junction strand network from the basal side; this is followed by slow replacement of older Claudins in the strands. In contrast, even at early times, newly synthesized occludin is found throughout the network. Taking the results together with our previous documentation of the mechanism for Claudin strand assembly in a fibroblast model, we speculate that newly synthesized Claudins are added at strand breaks and free ends; these are most common in the basalmost edge of the junction. In contrast, occludin can be added directly within the strand network. We further demonstrate that Claudin trafficking and half-life depend on carboxy-terminal sequences and that different Claudins compete for tight junction localization.
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visualizing the dynamic coupling of Claudin strands to the actin cytoskeleton through zo 1
Molecular Biology of the Cell, 2017Co-Authors: Christina M Van Itallie, Amber Jean Tietgens, James M. AndersonAbstract:The organization and integrity of epithelial tight junctions depend on interactions between Claudins, ZO scaffolding proteins, and the cytoskeleton. However, although binding between Claudins and ZO-1/2/3 and between ZO-1/2/3 and numerous cytoskeletal proteins has been demonstrated in vitro, fluorescence recovery after photobleaching analysis suggests interactions in vivo are likely highly dynamic. Here we use superresolution live-cell imaging in a model fibroblast system to examine relationships between Claudins, ZO-1, occludin, and actin. We find that GFP Claudins make easily visualized dynamic strand patches between two fibroblasts; strand dynamics is constrained by ZO-1 binding. Claudin association with actin is also dependent on ZO-1, but colocalization demonstrates intermittent rather than continuous association between Claudin, ZO-1, and actin. Independent of interaction with ZO-1 or actin, Claudin strands break and reanneal; pulse-chase-pulse analysis using SNAP-tagged Claudins showed preferential incorporation of newly synthesized Claudins into break sites. Although Claudin strand behavior in fibroblasts may not fully recapitulate that of epithelial tight junction strands, this is the first direct demonstration of the ability of ZO-1 to stabilize Claudin strands. We speculate that intermittent tethering of Claudins to actin may allow for accommodation of the paracellular seal to physiological or pathological alterations in cell shape or movement.
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sumoylation of Claudin 2
Annals of the New York Academy of Sciences, 2012Co-Authors: Christina M Van Itallie, Laura L Mitic, James M. AndersonAbstract:The C-terminal cytoplasmic tails of Claudins are likely sites for interaction with proteins that regulate their function. We performed a yeast two-hybrid screen with the tail of human Claudin-2 against a human kidney cDNA library and identified interactions with the PDZ3 domain of ZO-2 as well as ubiquitin-conjugating enzyme E2I (SUMO ligase-1) and E3 SUMO-protein ligase PIAS; the first is a predicted interaction, while the latter two are novel and suggest that Claudin-2 is a substrate for SUMOylation. Using an in vitro SUMOylation assay, we identified K218 as a conjugation site on Claudin-2; mutation of that lysine to arginine blocked SUMOylation. Stable expression of inducible GFP-SUMO-1 in MDCK cells resulted in decreased levels of Claudin-2 protein by immunoblot and decreased Claudin-2 membrane expression by immunofluorescence microscopy. We conclude that the cellular levels of Claudin-2 may be modulated by SUMOylation, warranting further investigation of cellular pathways that regulate this modification in vivo.
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Claudin 2 dependent changes in noncharged solute flux are mediated by the extracellular domains and require attachment to the pdz scaffold
Annals of the New York Academy of Sciences, 2009Co-Authors: Christina M. Van Itallie, Jennifer Holmes, Arlene S Bridges, James M. AndersonAbstract:Paracellular transport through the tight junction shows selectivity for both ionic charge and solute size. It is known that charged residues on the extracellular loops of Claudins control charge selectivity. It is also known that inducible expression of Claudin-2, but not Claudin-4, will selectively increase the permeability for PEG molecules which are <4A in radius, but it is not known whether permeability is controlled by the same regions of Claudins which control charge selectivity. Using inducible expression of chimeras of Claudin-2 and Claudin-4 in monolayers of MDCK II cells we show that the extracellular loops alone are responsible for controlling the permeability for noncharged PEGs as well as for charge selectivity. Further, the cytoplasmic C-terminal PDZ-binding motif is required for wild type Claudin-2 to control permeability, suggesting a requirement for attachment to the PDZ scaffold in order to form pores. These observations support a model where the loops form pores controlling permeability for both charged and noncharged solutes which are smaller than 4A. They leave unanswered why both Claudin-2 and -4 can influence electrical properties while only -2 can selectively increase permeability for small PEGs.
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Claudin 2 dependent changes in noncharged solute flux are mediated by the extracellular domains and require attachment to the pdz scaffold
Annals of the New York Academy of Sciences, 2009Co-Authors: Christina M Van Itallie, Jennifer Holmes, Arlene S Bridges, James M. AndersonAbstract:Paracellular transport through the tight junction shows selectivity for both ionic charge and solute size. It is known that charged residues on the extracellular loops of Claudins control charge selectivity. It is also known that inducible expression of Claudin-2, but not Claudin-4, will selectively increase the permeability for polyethylene glycol (PEG) molecules which are <0.4 A in radius, but it is not known whether permeability is controlled by the same regions of Claudins which control charge selectivity. Using inducible expression of chimeras of Claudin-2 and Claudin-4 in monolayers of MDCK II cells we show that the extracellular loops alone are responsible for controlling the permeability for noncharged PEGs as well as for charge selectivity. Further, the cytoplasmic C-terminal PDZ-binding motif is required for wild-type Claudin-2 to control permeability, suggesting a requirement for attachment to the PDZ scaffold in order to form pores. These observations support a model where the loops form pores controlling permeability for both charged and noncharged solutes which are smaller than 0.4 A. They leave unanswered why both Claudin-2 and -4 can influence electrical properties while only -2 can selectively increase permeability for small PEGs.
Ylermi Soini - One of the best experts on this subject based on the ideXlab platform.
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divergent expression of Claudin 1 3 4 5 and 7 in developing human lung
Respiratory Research, 2010Co-Authors: Heta Merikallio, Riitta Kaarteenaho, Siri Lehtonen, Terttu Harju, Ylermi SoiniAbstract:Claudins are the main components of tight junctions, structures which are associated with cell polarity and permeability. The aim of this study was to analyze the expression of Claudins 1, 3, 4, 5, and 7 in developing human lung tissues from 12 to 40 weeks of gestation. 47 cases were analyzed by immunohistochemisty for Claudins 1, 3, 4, 5 and 7. 23 cases were also investigated by quantitative RT-PCR for Claudin-1, -3 and -4. Claudin-1 was expressed in epithelium of bronchi and large bronchioles from week 12 onwards but it was not detected in epithelium of developing alveoli. Claudin-3, -4 and -7 were strongly expressed in bronchial epithelium from week 12 to week 40, and they were also expressed in alveoli from week 16 to week 40. Claudin-5 was expressed strongly during all periods in endothelial cells. It was expressed also in epithelium of bronchi from week 12 to week 40, and in alveoli during the canalicular period. RT-PCR analyses revealed detectable amounts of RNAs for Claudins 1, 3 and 4 in all cases studied. Claudin-1, -3, -4, -5, and -7 are expressed in developing human lung from week 12 to week 40 with distinct locations and in divergent quantities. The expression of Claudin-1 was restricted to the bronchial epithelium, whereas Claudin-3, -4 and -7 were positive also in alveolar epithelium as well as in the bronchial epithelium. All Claudins studied are linked to the development of airways, whereas Claudin-3, -4, -5 and -7, but not Claudin-1, are involved in the development of acinus and the differentiation of alveolar epithelial cells.
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Claudin 1 2 3 4 5 and 7 in usual interstitial pneumonia and sarcoidosis
Journal of Histochemistry and Cytochemistry, 2009Co-Authors: Riitta Kaarteenahowiik, Ylermi SoiniAbstract:The aim of this study was to study the expression of various Claudins in sarcoidosis, usual interstitial pneumonia (UIP), and normal human lung. The expression and cell-specific localization of Claudin-1, -2, -3, -4, -5, and -7 was analyzed by IHC. Bronchiolar epithelial cells showed mostly strong expression for Claudin-1, -2, -3, -4, and -7 and mainly weak expression for Claudin-5 in UIP, sarcoidosis, and normal lung. Three Claudins, Claudin-3, -4, and -7, were expressed in normal alveolar epithelium, mainly in type II pneumocytes. Claudin-5 was expressed strongly in endothelium of normal lung, and its staining was extremely intense in endothelium of UIP. Moderate or strong expression for Claudin-1, -2, -3, -4, and -7 was observed in metaplastic alveolar- and bronchiolar-type epithelium in UIP and also in metaplastic alveolar-type epithelium in sarcoidosis. Expression of Claudin-5 was mainly weak in metaplastic alveolar- and bronchiolar-type epithelium in UIP. We conclude that Claudin-1, -2, -3, -4, -5, and -7 are expressed in UIP and sarcoidosis, and furthermore, the most prominent enhancement of staining is localized in metaplastic alveolar- and bronchiolar-type epithelium in UIP compared with the healthy lung.
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Claudins 1 3 4 5 and 7 in esophageal cancer loss of Claudin 3 and 4 expression is associated with metastatic behavior
Apmis, 2007Co-Authors: Heikki Takala, Juha Saarnio, H Wiik, Ylermi SoiniAbstract:The aim of the study was to elucidate the significance of Claudins in surgically treated esophageal carcinoma. The expression of Claudins 1, 3, 4, 5 and 7 was studied by immunohistochemistry. Tumor proliferation was assessed with Ki67 immunostaining and apoptosis by the TUNEL method and immunostaining of fragmented caspase 3. Adenocarcinomas showed significantly more cases with moderate or strong Claudin 3 (p<0.001) and Claudin 5 positivity (p=0.031) compared to squamous cell carcinomas. Loss of Claudin 3 expression was associated with the presence of distant metastases (p=0.039). Claudins 3, 4 and 7 had a significant association with either a high apoptotic index or a high number of caspase 3-positive cells, while Claudin 5 was associated with increased proliferation. In esophageal carcinoma, Claudin expression may vary along with the histology of the tumor. Claudin expression may also be associated with apoptosis or proliferation, suggesting that Claudins may contribute to tumor behavior and growth.
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Claudins in differential diagnosis between mesothelioma and metastatic adenocarcinoma of the pleura
Journal of Clinical Pathology, 2006Co-Authors: Ylermi Soini, K Kahlos, Vuokko L Kinnula, Paavo PaakkoAbstract:Aim: To study the expression of Claudins in mesothelioma and metastatic pleural adenocarcinoma. Methods: Immunohistochemical staining of Claudins 1, 2, 3, 4, 5, and 7 was studied in 35 malignant mesotheliomas and the expression compared with 24 cases of pleural metastatic adenocarcinoma. All cases were also immunostained with calretinin. Results: Claudin 1, 2, 3, 4, 5, and 7 expression was seen in 40%, 80%, 18%, 23%, 14%, and 43% of mesotheliomas, respectively, while the corresponding figures for adenocarcinoma were 100%, 88%, 90%, 100%, 50%, and 92%. Claudins 1, 3, 4, 5, and 7 were significantly less positive in mesothelioma than in metastatic adenocarcinoma, while no difference was observed for Claudin 2. Claudins 1, 3, 4, 5, and 7 were also inversely associated with calretinin positivity. Sarcomatoid and biphasic mesothelioma subtypes appeared more negative for these Claudins than pure epithelioid subtypes. Claudin expression was not associated with survival of patients with malignant mesotheliomas. Conclusions: The results show that malignant mesotheliomas have a lower expression of Claudins 1, 3, 4, 5, and 7 than adenocarcinomas, and their expression could thus be used as an adjunct in differential diagnosis between the two. The difference was most evident for Claudins 3 and 4, which were nearly as good as calretinin in mesothelioma detection. Sarcomatoid and biphasic mesotheliomas showed expression of these Claudins only occasionally, which could be due to or contribute to their less epithelial appearance.
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Claudins 1 3 4 and 5 in gastric carcinoma loss of Claudin expression associates with the diffuse subtype
Virchows Archiv, 2006Co-Authors: Ylermi Soini, S Tommola, Heikki Helin, Paula M MartikainenAbstract:In this study expression of Claudins 1, 3, 4 and 5 were studied in 118 cases of gastric carcinoma and compared with proliferation, apoptosis and E-cadherin expression. Expression of all these Claudins could be seen in gastric carcinoma, most prominently for Claudin 4, and least expression was found for Claudin 5. All Claudins showed significantly more expression in gastric carcinomas of intestinal type. Their expression was significantly associated with each other. Expression of Claudins 4 and 5 was associated with E-cadherin. Strong expression of Claudin 5 was associated with higher cell proliferation and apoptosis. Claudin 3 expression had an association with a better prognosis of the patients, especially in the intestinal type. The results show that expression of Claudins 1, 3, 4 and 5 is lower in diffuse-type gastric carcinomas. Possibly they play a role in determining the diffuse phenotype and loose cohesion of cells in diffuse type of gastric carcinoma in a similar manner as E-cadherin. The loss of their expression does not clearly associate with poorer prognosis of the patients, except for Claudin 3, where strong expression was associated with a better outcome of the patients, a feature especially related to intestinal-type tumours.
Shoichiro Tsukita - One of the best experts on this subject based on the ideXlab platform.
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differential expression patterns of Claudins tight junction membrane proteins in mouse nephron segments
Journal of The American Society of Nephrology, 2002Co-Authors: Yumiko Kiuchisaishin, Mikio Furuse, Shimpei Gotoh, Akiko Takasuga, Yasuo Tano, Shoichiro TsukitaAbstract:ABSTRACT. As the first step in understanding the physiologic functions of Claudins (tight junction integral membrane proteins) in nephrons, the expression of Claudin-1 to -16 in mouse kidneys was examined by Northern blotting. Among these Claudins, only Claudin-6, -9, -13, and -14 were not detectable. Claudin-5 and -15 were detected only in endothelial cells. Polyclonal antibodies specific for Claudin-7 and -12 were not available. Therefore, the distributions of Claudin-1, -2, -3, -4, -8, -10, -11, and -16 in nephron segments were examined with immunofluorescence microscopy. For identification of individual segments, antibodies specific for segment markers were used. Immunofluorescence microscopic analyses of serial frozen sections of mouse kidneys with polyclonal antibodies for Claudins and segment markers revealed that Claudins demonstrated very complicated, segment-specific, expression patterns in nephrons, i.e. , Claudin-1 and -2 in Bowman’s capsule, Claudin-2, -10, and -11 in the proximal tubule, Claudin-2 in the thin descending limb of Henle, Claudin-3, -4, and -8 in the thin ascending limb of Henle, Claudin-3, -10, -11, and -16 in the thick ascending limb of Henle, Claudin-3 and -8 in the distal tubule, and Claudin-3, -4, and -8 in the collecting duct. These segment-specific expression patterns of Claudins are discussed, with special reference to the physiologic functions of tight junctions in nephrons.
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clostridium perfringens enterotoxin binds to the second extracellular loop of Claudin 3 a tight junction integral membrane protein
FEBS Letters, 2000Co-Authors: Kohji Fujita, Mikio Furuse, Jun Katahira, Yasuhiko Horiguchi, Noriyuki Sonoda, Shoichiro TsukitaAbstract:Abstract Claudins (Claudin-1 to -18) with four transmembrane domains and two extracellular loops constitute tight junction strands. The peptide toxin Clostridium perfringens enterotoxin (CPE) has been shown to bind to Claudin-3 and -4, but not to Claudin-1 or -2. We constructed Claudin-1/Claudin-3 chimeric molecules and found that the second extracellular loop of Claudin-3 conferred CPE sensitivity on L fibroblasts. Furthermore, overlay analyses revealed that the second extracellular loop of Claudin-3 specifically bound to CPE at the K a value of 1.0×10 8 M −1 . We concluded that the second extracellular loop is the site through which Claudin-3 interacts with CPE on the cell surface.
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direct binding of three tight junction associated maguks zo 1 zo 2 and zo 3 with the cooh termini of Claudins
Journal of Cell Biology, 1999Co-Authors: Masahiko Itoh, Mikio Furuse, Kazumasa Morita, Koji Kubota, Mitinori Saitou, Shoichiro TsukitaAbstract:ZO-1, ZO-2, and ZO-3, which contain three PDZ domains (PDZ1 to -3), are concentrated at tight junctions (TJs) in epithelial cells. TJ strands are mainly composed of two distinct types of four-transmembrane proteins, occludin, and Claudins, between which occludin was reported to directly bind to ZO-1/ZO-2/ZO-3. However, in occludin-deficient intestinal epithelial cells, ZO-1/ZO-2/ZO-3 were still recruited to TJs. We then examined the possible interactions between ZO-1/ZO-2/ZO-3 and Claudins. ZO-1, ZO-2, and ZO-3 bound to the COOH-terminal YV sequence of Claudin-1 to -8 through their PDZ1 domains in vitro. Then, Claudin-1 or -2 was transfected into L fibroblasts, which express ZO-1 but not ZO-2 or ZO-3. Claudin-1 and -2 were concentrated at cell–cell borders in an elaborate network pattern, to which endogenous ZO-1 was recruited. When ZO-2 or ZO-3 were further transfected, both were recruited to the Claudin-based networks together with endogenous ZO-1. Detailed analyses showed that ZO-2 and ZO-3 are recruited to the Claudin-based networks through PDZ2 (ZO-2 or ZO-3)/PDZ2 (endogenous ZO-1) and PDZ1 (ZO-2 or ZO-3)/COOH-terminal YV (Claudins) interactions. In good agreement, PDZ1 and PDZ2 domains of ZO-1/ZO-2/ZO-3 were also recruited to Claudin-based TJs, when introduced into cultured epithelial cells. The possible molecular architecture of TJ plaque structures is discussed.
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manner of interaction of heterogeneous Claudin species within and between tight junction strands
Journal of Cell Biology, 1999Co-Authors: Mikio Furuse, Hiroyuki Sasaki, Shoichiro TsukitaAbstract:In tight junctions (TJs), TJ strands are associated laterally with those of adjacent cells to form paired strands to eliminate the extracellular space. Claudin-1 and -2, integral membrane proteins of TJs, reconstitute paired TJ strands when transfected into L fibroblasts. Claudins comprise a multigene family and more than two distinct Claudins are coexpressed in single cells, raising the questions of whether heterogeneous Claudins form heteromeric TJ strands and whether Claudins interact between each of the paired strands in a heterophilic manner. To answer these questions, we cotransfected two of Claudin-1, -2, and -3 into L cells, and detected their coconcentration at cell–cell borders as elaborate networks. Immunoreplica EM confirmed that distinct Claudins were coincorporated into individual TJ strands. Next, two L transfectants singly expressing Claudin-1, -2, or -3 were cocultured and we found that Claudin-3 strands laterally associated with Claudin-1 and -2 strands to form paired strands, whereas Claudin-1 strands did not interact with Claudin-2 strands. We concluded that distinct species of Claudins can interact within and between TJ strands, except in some combinations. This mode of assembly of Claudins could increase the diversity of the structure and functions of TJ strands.
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clostridium perfringens enterotoxin fragment removes specific Claudins from tight junction strands evidence for direct involvement of Claudins in tight junction barrier
Journal of Cell Biology, 1999Co-Authors: Noriyuki Sonoda, Mikio Furuse, Hiroyuki Sasaki, Jun Katahira, Yasuhiko Horiguchi, Shigenobu Yonemura, Shoichiro TsukitaAbstract:Claudins, comprising a multigene family, constitute tight junction (TJ) strands. Clostridium perfringens enterotoxin (CPE), a single ∼35-kD polypeptide, was reported to specifically bind to Claudin-3/RVP1 and Claudin-4/CPE-R at its COOH-terminal half. We examined the effects of the COOH-terminal half fragment of CPE (C-CPE) on TJs in L transfectants expressing Claudin-1 to -4 (C1L to C4L, respectively), and in MDCK I cells expressing Claudin-1 and -4. C-CPE bound to Claudin-3 and -4 with high affinity, but not to Claudin-1 or -2. In the presence of C-CPE, reconstituted TJ strands in C3L cells gradually disintegrated and disappeared from their cell surface. In MDCK I cells incubated with C-CPE, Claudin-4 was selectively removed from TJs with its concomitant degradation. At 4 h after incubation with C-CPE, TJ strands were disintegrated, and the number of TJ strands and the complexity of their network were markedly decreased. In good agreement with the time course of these morphological changes, the TJ barrier (TER and paracellular flux) of MDCK I cells was downregulated by C-CPE in a dose-dependent manner. These findings provided evidence for the direct involvement of Claudins in the barrier functions of TJs.
Mikio Furuse - One of the best experts on this subject based on the ideXlab platform.
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Claudins and jam a coordinately regulate tight junction formation and epithelial polarity
Journal of Cell Biology, 2019Co-Authors: Tetsuhisa Otani, Shinsaku Tokuda, Thanh Phuong Nguyen, Kei Sugihara, Taichi Sugawara, Kyoko Furuse, Takashi Miura, Klaus Ebnet, Mikio FuruseAbstract:Tight junctions (TJs) establish the epithelial barrier and are thought to form a membrane fence to regulate epithelial polarity, although the roles of TJs in epithelial polarity remain controversial. Claudins constitute TJ strands in conjunction with the cytoplasmic scaffolds ZO-1 and ZO-2 and play pivotal roles in epithelial barrier formation. However, how Claudins and other TJ membrane proteins cooperate to organize TJs remains unclear. Here, we systematically knocked out TJ components by genome editing and show that while ZO-1/ZO-2-deficient cells lacked TJ structures and epithelial barriers, Claudin-deficient cells lacked TJ strands and an electrolyte permeability barrier but formed membrane appositions and a macromolecule permeability barrier. Moreover, epithelial polarity was disorganized in ZO-1/ZO-2-deficient cells, but not in Claudin-deficient cells. Simultaneous deletion of Claudins and a TJ membrane protein JAM-A resulted in a loss of membrane appositions and a macromolecule permeability barrier and in sporadic epithelial polarity defects. These results demonstrate that Claudins and JAM-A coordinately regulate TJ formation and epithelial polarity.
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Claudin 4 knockout by talen mediated gene targeting in mdck cells Claudin 4 is dispensable for the permeability properties of tight junctions in wild type mdck cells
PLOS ONE, 2017Co-Authors: Shinsaku Tokuda, Toyohiro Hirai, Mikio FuruseAbstract:Epithelia act as a barrier between the internal and external environments, and the movement of substances via the paracellular pathway is regulated by tight junctions (TJs). Claudins are major determinants of TJ permeability. Claudin-4 was the first Claudin whose involvement in the TJ permeability in cultured cells was directly demonstrated, but the permeability properties of individual Claudins including Claudin-4 are still incompletely clarified. In this study, we established Claudin-4 knockout cells using transcription activator-like effector nucleases (TALENs), a recently developed method for genome editing, and investigated the permeability property of Claudin-4 in MDCK II cells. We found that Claudin-4 knockout has no apparent effect on the localization of other Claudins and electrophysiological properties in MDCK II cells. Therefore we further established Claudin-2 and Claudin-4 double knockout clones and investigated the effects on TJs. Claudin-4 knockout in addition to Claudin-2 knockout slightly increased the localization of other Claudins at TJs but showed no obvious effects on the electrophysiological properties in MDCK II cells. These results indicate that Claudin-4 is dispensable for the barrier property of TJs in wild-type as well as Claudin-2 knockout MDCK II cells. Our results suggest the need for further knockout analysis to reveal the permeability properties of individual Claudins.
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differential expression patterns of Claudins tight junction membrane proteins in mouse nephron segments
Journal of The American Society of Nephrology, 2002Co-Authors: Yumiko Kiuchisaishin, Mikio Furuse, Shimpei Gotoh, Akiko Takasuga, Yasuo Tano, Shoichiro TsukitaAbstract:ABSTRACT. As the first step in understanding the physiologic functions of Claudins (tight junction integral membrane proteins) in nephrons, the expression of Claudin-1 to -16 in mouse kidneys was examined by Northern blotting. Among these Claudins, only Claudin-6, -9, -13, and -14 were not detectable. Claudin-5 and -15 were detected only in endothelial cells. Polyclonal antibodies specific for Claudin-7 and -12 were not available. Therefore, the distributions of Claudin-1, -2, -3, -4, -8, -10, -11, and -16 in nephron segments were examined with immunofluorescence microscopy. For identification of individual segments, antibodies specific for segment markers were used. Immunofluorescence microscopic analyses of serial frozen sections of mouse kidneys with polyclonal antibodies for Claudins and segment markers revealed that Claudins demonstrated very complicated, segment-specific, expression patterns in nephrons, i.e. , Claudin-1 and -2 in Bowman’s capsule, Claudin-2, -10, and -11 in the proximal tubule, Claudin-2 in the thin descending limb of Henle, Claudin-3, -4, and -8 in the thin ascending limb of Henle, Claudin-3, -10, -11, and -16 in the thick ascending limb of Henle, Claudin-3 and -8 in the distal tubule, and Claudin-3, -4, and -8 in the collecting duct. These segment-specific expression patterns of Claudins are discussed, with special reference to the physiologic functions of tight junctions in nephrons.
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clostridium perfringens enterotoxin binds to the second extracellular loop of Claudin 3 a tight junction integral membrane protein
FEBS Letters, 2000Co-Authors: Kohji Fujita, Mikio Furuse, Jun Katahira, Yasuhiko Horiguchi, Noriyuki Sonoda, Shoichiro TsukitaAbstract:Abstract Claudins (Claudin-1 to -18) with four transmembrane domains and two extracellular loops constitute tight junction strands. The peptide toxin Clostridium perfringens enterotoxin (CPE) has been shown to bind to Claudin-3 and -4, but not to Claudin-1 or -2. We constructed Claudin-1/Claudin-3 chimeric molecules and found that the second extracellular loop of Claudin-3 conferred CPE sensitivity on L fibroblasts. Furthermore, overlay analyses revealed that the second extracellular loop of Claudin-3 specifically bound to CPE at the K a value of 1.0×10 8 M −1 . We concluded that the second extracellular loop is the site through which Claudin-3 interacts with CPE on the cell surface.
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direct binding of three tight junction associated maguks zo 1 zo 2 and zo 3 with the cooh termini of Claudins
Journal of Cell Biology, 1999Co-Authors: Masahiko Itoh, Mikio Furuse, Kazumasa Morita, Koji Kubota, Mitinori Saitou, Shoichiro TsukitaAbstract:ZO-1, ZO-2, and ZO-3, which contain three PDZ domains (PDZ1 to -3), are concentrated at tight junctions (TJs) in epithelial cells. TJ strands are mainly composed of two distinct types of four-transmembrane proteins, occludin, and Claudins, between which occludin was reported to directly bind to ZO-1/ZO-2/ZO-3. However, in occludin-deficient intestinal epithelial cells, ZO-1/ZO-2/ZO-3 were still recruited to TJs. We then examined the possible interactions between ZO-1/ZO-2/ZO-3 and Claudins. ZO-1, ZO-2, and ZO-3 bound to the COOH-terminal YV sequence of Claudin-1 to -8 through their PDZ1 domains in vitro. Then, Claudin-1 or -2 was transfected into L fibroblasts, which express ZO-1 but not ZO-2 or ZO-3. Claudin-1 and -2 were concentrated at cell–cell borders in an elaborate network pattern, to which endogenous ZO-1 was recruited. When ZO-2 or ZO-3 were further transfected, both were recruited to the Claudin-based networks together with endogenous ZO-1. Detailed analyses showed that ZO-2 and ZO-3 are recruited to the Claudin-based networks through PDZ2 (ZO-2 or ZO-3)/PDZ2 (endogenous ZO-1) and PDZ1 (ZO-2 or ZO-3)/COOH-terminal YV (Claudins) interactions. In good agreement, PDZ1 and PDZ2 domains of ZO-1/ZO-2/ZO-3 were also recruited to Claudin-based TJs, when introduced into cultured epithelial cells. The possible molecular architecture of TJ plaque structures is discussed.
András Kiss - One of the best experts on this subject based on the ideXlab platform.
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Claudins and tricellulin in fibrolamellar hepatocellular carcinoma
Virchows Archiv, 2011Co-Authors: Attila Patonai, Áron Somorácz, Anna Korompay, Boglárka Erdélyi-belle, Gábor Lotz, András Kiss, Beate K. Straub, Peter Schirmacher, Ilona Kovalszky, Zsuzsa SchaffAbstract:Fibrolamellar hepatocellular carcinoma is a subtype of hepatocellular carcinoma occurring in non-cirrhotic liver at a younger age. The tumor expresses both hepatocellular and cholangiocellular markers. Previously, our group described overexpression of tight junction protein Claudin 4 in cholangiocellular carcinoma in contrast to hepatocellular carcinoma. In the present study, tight junction protein expressions were studied to possibly clarify bipotential lineage of fibrolamellar hepatocellular carcinoma. Eleven fibrolamellar hepatocellular carcinomas were compared with seven “conventional” hepatocellular carcinomas, seven cholangiocellular carcinomas, and five normal liver samples. By immunohistochemistry, all fibrolamellar hepatocellular carcinomas were positive for HepPar1 and cytokeratins 7, 8, and 18, but negative for cytokeratin 19. Glypican-3 gave weak staining in two cases. Expression of Claudin 1 was lower, while that of Claudin 2 was higher in fibrolamellar hepatocellular carcinomas than in other tumors. Claudins 3, 4, and 7 were not detectable in fibrolamellar hepatocellular carcinomas as in the majority of “conventional” hepatocellular carcinomas, contrary to high expression observed in cholangiocellular carcinomas. Focal or diffuse Claudin 5 expression was detected in nine of 11 fibrolamellar hepatocellular carcinomas contrary to other tumors. Tricellulin was significantly downregulated in all tumors compared with normal liver. Our findings showed Claudins to exhibit specific expression patterns in fibrolamellar hepatocellular carcinomas not observed in other primary liver tumors, with unique Claudin 5 expression and pattern features similar to common hepatocellular carcinoma, but different from cholangiocellular carcinoma. This is the first report describing the loss of tricellulin expression in human hepatic tumors.
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Claudin 1 2 3 4 7 8 and 10 protein expression in biliary tract cancers
Journal of Histochemistry and Cytochemistry, 2009Co-Authors: Zsuzsanna Nemeth, Áron Somorácz, András Kiss, Attila Marcell Szasz, Attila Szijártó, Péter Kupcsulik, Peter Tatrai, Julia Nemeth, Hajnalka Gyorffy, Zsuzsa SchaffAbstract:Biliary tract cancers are relatively common malignant gastrointestinal tumors in the elderly. Claudins are integral components of tight junctions that play important roles in maintaining epithelial cell polarity, controlling paracellular diffusion, and regulating cell growth and differentiation. The expression profile of Claudins has been extensively characterized, but few reports exist on their expression in the normal and neoplastic biliary tract. Our aim was therefore to study Claudins by IHC reactions in normal and neoplastic biliary tract samples. We detected that Claudin expressions differ in the normal sample groups: the normal gallbladder strongly expressed Claudin-2, -3, -4, and -10, but only weak reactions were seen in normal intrahepatic bile ducts. Although each cancer type expressed several Claudins with various intensities, only Claudin-4 presented especially strong immunoreactions in extrahepatic bile duct cancers and gallbladder carcinomas, whereas Claudin-1 and -10 presented in intrahepatic bile duct cancers. Comparing the normal and carcinoma groups, the most significant decrease was detected in the expression of Claudin-10. In conclusion, the expression pattern of Claudins is different in the various parts of the normal and neoplastic biliary tract; moreover, an unequivocal decrease was detected in the carcinomas compared with their corresponding normal samples. This manuscript contains online supplemental material at http://www.jhc.org. Please visit this article online to view these materials.
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expression and localisation of Claudin 1 2 3 4 5 7 and 10 proteins in the normal canine mammary gland
Acta Veterinaria Hungarica, 2008Co-Authors: Csaba Jakab, Zsuzsa Schaff, András Kiss, Judit Halasz, Attila Marcell Szasz, Enkhjargal Batmunkh, Miklos Rusvai, Peter Galfi, Janina KulkaAbstract:The recently identified Claudins are dominant components of tight junctions, responsible for cell adhesion, polarity and paracellular permeability. Certain Claudins have been shown to have relevance in tumour development. The aim of the present study was to analyse the expression of Claudin-1,-2,-3,-4,-5,-7 and-10 in normal canine mammary glands. Samples from the inguinal mammary regions of 20 non-castrated, 1–13 years old female dogs were studied. Immunohistochemical analysis was performed on conventional specimens and tissue microarrays. The results of the immunohistochemical reactions detecting Claudins in tissue sections were photodocumented. The immunoreactivity of Claudins was quantitatively analysed on digital images using Leica QWin morphometry software. Intense membranous immunolabelling was found for Claudin-1,-3 and-7, intense membranous with non-granular cytoplasmic immunolabelling for Claudin-2, moderate membranous immunolabelling for Claudin-4 and-5, and weak membranous immunolabelling for c...
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Claudin-4 differentiates biliary tract cancers from hepatocellular carcinomas.
Modern Pathology, 2006Co-Authors: Csaba Lódi, Ilona Kovalszky, Enkhjargal Batmunkh, Erzsébet Szabó, Ágnes Holczbauer, Attila Szijártó, Péter Kupcsulik, Sándor Paku, György Illyés, András KissAbstract:The recently identified Claudins are dominant components of tight junctions, responsible for cell adhesion, polarity and paracellular permeability. Certain Claudins have been shown to have relevance in tumor development, with some of them, especially Claudin-4, even suggested as future therapeutic target. The aim of the present study was to analyze the expression of Claudin-4 in the biliary tree, biliary tract cancers and hepatocellular carcinomas. A total of 107 cases were studied: 53 biliary tract cancers, 50 hepatocellular carcinomas, 10 normal liver and 10 normal extrahepatic biliary duct samples. Immunohistochemical analysis was performed on conventional specimens and on tissue microarrays as well. Claudin-4 was further investigated by Western blot analysis and real-time RT-PCR. Intense membranous immunolabeling was found for Claudin-4 in all biliary tract cancers unrelated to the primary site of origin, namely intrahepatic, extrahepatic or gallbladder cancers. Normal biliary epithelium showed weak positivity for Claudin-4. In contrast, normal hepatocytes and tumor cells of hepatocellular carcinomas did not express Claudin-4. The results of Western immunoblot analysis and real-time RT-PCR were in correlation with the immunohistochemical findings. Cytokeratins, as CK7 (92%) and CK19 (83%) were mostly positive in biliary tract cancers, however, one-third of hepatocellular carcinomas also expressed CK7 (34%). HSA antibody (HepPar1) reacted with the majority of hepatocellular carcinomas (86%), while being positive in a low percentage of the biliary tract cancers (8%). In conclusion, this is the first report of a significantly increased Claudin-4 expression in biliary tract cancers, which represents a novel feature of tumors of biliary tract origin. Claudin-4 expression seems to be a useful marker in differentiating biliary tract cancers from hepatocellular carcinomas and could well become a potential diagnostic tool.
