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Yu D, Peng Z, Wu H, Zhang X, Ji C, Peng X. Stress responses in expressions of microRNAs in mussel Mytilus galloprovincialis exposed to cadmium. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2021; 212:111927. [PMID: 33508712 DOI: 10.1016/j.ecoenv.2021.111927] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/06/2020] [Revised: 01/06/2021] [Accepted: 01/10/2021] [Indexed: 06/12/2023]
Abstract
MicroRNAs (miRNAs) are known to have complicated functions in aquatic species, but little is known about the role of miRNAs in mollusk species under environmental stress. In this study, we performed small RNA sequencing to characterize the differentially expressed miRNAs in different tissues (whole tissues, digestive glands, gills, and gonads) of blue mussels (Mytilus galloprovincialis) exposed to cadmium (Cd). In summary, 107 known miRNAs and 32 novel miRNAs were significantly (p < 0.01) differentially expressed after Cd exposure. The peak size of miRNAs was 22 nucleotides. Target genes of these differentially expressions of miRNAs related to immune defense, apoptosis, lipid and xenobiotic metabolism showed significant changes under Cd stress. These findings provide the first characterization of miRNAs in mussel M. galloprovincialis and expressions of many target genes in response to Cd stress.
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Affiliation(s)
- Deliang Yu
- Center for Biomedical Optics and Photonics (CBOP) & College of Physics and Optoelectronic Engineering, Key Laboratory of Optoelectronic Devices and Systems, Shenzhen University, Shenzhen 518060, PR China; Laboratory for Marine Fisheries Science and Food Production Processes, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266237, PR China; Qingdao National Laboratory for Marine Science and Technology, Qingdao 266237, PR China
| | - Zheng Peng
- Center for Biomedical Optics and Photonics (CBOP) & College of Physics and Optoelectronic Engineering, Key Laboratory of Optoelectronic Devices and Systems, Shenzhen University, Shenzhen 518060, PR China
| | - Huifeng Wu
- Laboratory for Marine Fisheries Science and Food Production Processes, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266237, PR China; Shandong Key Laboratory of Coastal Environmental Processes, YICCAS, Yantai 264003, PR China; CAS Key Laboratory of Coastal Environmental Processes and Ecological Remediation, Yantai Institute of Coastal Zone Research (YIC), Chinese Academy of Sciences (CAS), YICCAS, Yantai 264003, PR China; Center for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao 266071, PR China.
| | - Xiaoying Zhang
- AstraZeneca-Shenzhen University Joint Institute of Nephrology, Department of Physiology, Shenzhen University Health Science Center, Shenzhen University, Shenzhen 518060, PR China
| | - Chenglong Ji
- Laboratory for Marine Fisheries Science and Food Production Processes, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266237, PR China; Shandong Key Laboratory of Coastal Environmental Processes, YICCAS, Yantai 264003, PR China; CAS Key Laboratory of Coastal Environmental Processes and Ecological Remediation, Yantai Institute of Coastal Zone Research (YIC), Chinese Academy of Sciences (CAS), YICCAS, Yantai 264003, PR China; Center for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao 266071, PR China
| | - Xiao Peng
- Center for Biomedical Optics and Photonics (CBOP) & College of Physics and Optoelectronic Engineering, Key Laboratory of Optoelectronic Devices and Systems, Shenzhen University, Shenzhen 518060, PR China.
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2
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Li F, Egea PF, Vecchio AJ, Asial I, Gupta M, Paulino J, Bajaj R, Dickinson MS, Ferguson-Miller S, Monk BC, Stroud RM. Highlighting membrane protein structure and function: A celebration of the Protein Data Bank. J Biol Chem 2021; 296:100557. [PMID: 33744283 PMCID: PMC8102919 DOI: 10.1016/j.jbc.2021.100557] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2020] [Revised: 02/10/2021] [Accepted: 03/16/2021] [Indexed: 12/13/2022] Open
Abstract
Biological membranes define the boundaries of cells and compartmentalize the chemical and physical processes required for life. Many biological processes are carried out by proteins embedded in or associated with such membranes. Determination of membrane protein (MP) structures at atomic or near-atomic resolution plays a vital role in elucidating their structural and functional impact in biology. This endeavor has determined 1198 unique MP structures as of early 2021. The value of these structures is expanded greatly by deposition of their three-dimensional (3D) coordinates into the Protein Data Bank (PDB) after the first atomic MP structure was elucidated in 1985. Since then, free access to MP structures facilitates broader and deeper understanding of MPs, which provides crucial new insights into their biological functions. Here we highlight the structural and functional biology of representative MPs and landmarks in the evolution of new technologies, with insights into key developments influenced by the PDB in magnifying their impact.
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Affiliation(s)
- Fei Li
- Department of Biochemistry and Biophysics, University of California San Francisco, San Francisco, California, USA; Department of Neurology, University of California San Francisco, San Francisco, California, USA
| | - Pascal F Egea
- Department of Biological Chemistry, School of Medicine, University of California Los Angeles, Los Angeles, California, USA
| | - Alex J Vecchio
- Department of Biochemistry, University of Nebraska-Lincoln, Lincoln, Nebraska, USA
| | | | - Meghna Gupta
- Department of Biochemistry and Biophysics, University of California San Francisco, San Francisco, California, USA
| | - Joana Paulino
- Department of Biochemistry and Biophysics, University of California San Francisco, San Francisco, California, USA
| | - Ruchika Bajaj
- Department of Bioengineering and Therapeutic Sciences, University of California San Francisco, San Francisco, California, USA
| | - Miles Sasha Dickinson
- Department of Biochemistry and Biophysics, University of California San Francisco, San Francisco, California, USA
| | - Shelagh Ferguson-Miller
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, Michigan, USA
| | - Brian C Monk
- Sir John Walsh Research Institute and Department of Oral Sciences, University of Otago, North Dunedin, Dunedin, New Zealand
| | - Robert M Stroud
- Department of Biochemistry and Biophysics, University of California San Francisco, San Francisco, California, USA.
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3
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Shima A, Matsuoka H, Yamaoka A, Michihara A. Transcription of CLDND1 in human brain endothelial cells is regulated by the myeloid zinc finger 1. Clin Exp Pharmacol Physiol 2020; 48:260-269. [PMID: 33037622 DOI: 10.1111/1440-1681.13416] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2020] [Revised: 09/12/2020] [Accepted: 10/05/2020] [Indexed: 12/01/2022]
Abstract
Increased permeability of endothelial cells lining the blood vessels in the brain leads to vascular oedema and, potentially, to stroke. The tight junctions (TJs), primarily responsible for the regulation of vascular permeability, are multi-protein complexes comprising the claudin family of proteins and occludin. Several studies have reported that downregulation of the claudin domain containing 1 (CLDND1) gene enhances vascular permeability, which consequently increases the risk of stroke. However, the transcriptional regulation of CLDND1 has not been studied extensively. Therefore, this study aimed to identify the transcription factors (TFs) regulating CLDND1 expression. A luciferase reporter assay identified a silencer within the first intron of CLDND1, which was identified as a potential binding site of the myeloid zinc finger 1 (MZF1) through in silico and TFBIND software analyses, and confirmed through a reporter assay using the MZF1 expression vector and chromatin immunoprecipitation (ChIP) assays. Moreover, the transient overexpression of MZF1 significantly increased the mRNA and protein expression levels of CLDND1, conversely, which were suppressed through the siRNA-mediated MZF1 knockdown. Furthermore, the permeability of FITC-dextran was observed to be increased on MZF1 knockdown as compared to that of the siGFP control. Our data revealed the underlying mechanism of the transcriptional regulation of CLDND1 by the MZF1. The findings suggest a potential role of MZF1 in TJ formation, which could be studied further and applied to prevent cerebral haemorrhage.
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Affiliation(s)
- Akiho Shima
- Laboratory of Genomic Function and Pathophysiology, Faculty of Pharmacy and Pharmaceutical Sciences, Fukuyama University, Fukuyama, Japan
| | - Hiroshi Matsuoka
- Laboratory of Genomic Function and Pathophysiology, Faculty of Pharmacy and Pharmaceutical Sciences, Fukuyama University, Fukuyama, Japan
| | - Alice Yamaoka
- Laboratory of Genomic Function and Pathophysiology, Faculty of Pharmacy and Pharmaceutical Sciences, Fukuyama University, Fukuyama, Japan
| | - Akihiro Michihara
- Laboratory of Genomic Function and Pathophysiology, Faculty of Pharmacy and Pharmaceutical Sciences, Fukuyama University, Fukuyama, Japan
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4
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The Intestinal Barrier and Current Techniques for the Assessment of Gut Permeability. Cells 2020; 9:cells9081909. [PMID: 32824536 PMCID: PMC7463717 DOI: 10.3390/cells9081909] [Citation(s) in RCA: 198] [Impact Index Per Article: 49.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2020] [Revised: 08/07/2020] [Accepted: 08/14/2020] [Indexed: 02/08/2023] Open
Abstract
The intestinal barrier is essential in human health and constitutes the interface between the outside and the internal milieu of the body. A functional intestinal barrier allows absorption of nutrients and fluids but simultaneously prevents harmful substances like toxins and bacteria from crossing the intestinal epithelium and reaching the body. An altered intestinal permeability, a sign of a perturbed barrier function, has during the last decade been associated with several chronic conditions, including diseases originating in the gastrointestinal tract but also diseases such as Alzheimer and Parkinson disease. This has led to an intensified interest from researchers with diverse backgrounds to perform functional studies of the intestinal barrier in different conditions. Intestinal permeability is defined as the passage of a solute through a simple membrane and can be measured by recording the passage of permeability markers over the epithelium via the paracellular or the transcellular route. The methodological tools to investigate the gut barrier function are rapidly expanding and new methodological approaches are being developed. Here we outline and discuss, in vivo, in vitro and ex vivo techniques and how these methods can be utilized for thorough investigation of the intestinal barrier.
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Huang L, Yang Y, Yang F, Liu S, Zhu Z, Lei Z, Guo J. Functions of EpCAM in physiological processes and diseases (Review). Int J Mol Med 2018; 42:1771-1785. [PMID: 30015855 PMCID: PMC6108866 DOI: 10.3892/ijmm.2018.3764] [Citation(s) in RCA: 70] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2018] [Accepted: 07/04/2018] [Indexed: 12/14/2022] Open
Abstract
EpCAM (epithelial cell adhesion molecule) is a type I transmembrane glycoprotein, which was originally identified as a tumor-associated antigen due to its high expression level in rapidly growing epithelial tumors. Germ line mutations of the human EpCAM gene have been indicated as the cause of congenital tufting enteropathy. Previous studies based on cell models have revealed that EpCAM contributes to various biological processes including cell adhesion, signaling, migration and proliferation. Due to the previous lack of genetic animal models, the in vivo functions of EpCAM remain largely unknown. However, EpCAM genetic animal models have recently been generated, and are useful for understanding the functions of EpCAM. The authors here briefly review the functions and mechanisms of EpCAM in physiological processes and different diseases.
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Affiliation(s)
- Li Huang
- Guangdong Metabolic Disease Research Center of Integrated Chinese and Western Medicine, Guangdong Pharmaceutical University, Guangzhou Higher Education Mega Center, Guangzhou, Guangdong 510006, P.R. China
| | - Yanhong Yang
- The First Affiliated Hospital, School of Clinical Medicine, Guangdong Pharmaceutical University, Guangzhou, Guangdong 510080, P.R. China
| | - Fei Yang
- Guangdong Metabolic Disease Research Center of Integrated Chinese and Western Medicine, Guangdong Pharmaceutical University, Guangzhou Higher Education Mega Center, Guangzhou, Guangdong 510006, P.R. China
| | - Shaomin Liu
- Guangdong Metabolic Disease Research Center of Integrated Chinese and Western Medicine, Guangdong Pharmaceutical University, Guangzhou Higher Education Mega Center, Guangzhou, Guangdong 510006, P.R. China
| | - Ziqin Zhu
- Guangdong Metabolic Disease Research Center of Integrated Chinese and Western Medicine, Guangdong Pharmaceutical University, Guangzhou Higher Education Mega Center, Guangzhou, Guangdong 510006, P.R. China
| | - Zili Lei
- Guangdong Metabolic Disease Research Center of Integrated Chinese and Western Medicine, Guangdong Pharmaceutical University, Guangzhou Higher Education Mega Center, Guangzhou, Guangdong 510006, P.R. China
| | - Jiao Guo
- Guangdong Metabolic Disease Research Center of Integrated Chinese and Western Medicine, Guangdong Pharmaceutical University, Guangzhou Higher Education Mega Center, Guangzhou, Guangdong 510006, P.R. China
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6
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Abramczyk H, Brozek-Pluska B. Apical-basal polarity of epithelial cells imaged by Raman microscopy and Raman imaging: Capabilities and challenges for cancer research. J Mol Liq 2017. [DOI: 10.1016/j.molliq.2017.05.142] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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7
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Abba ML, Patil N, Leupold JH, Allgayer H. MicroRNA Regulation of Epithelial to Mesenchymal Transition. J Clin Med 2016; 5:jcm5010008. [PMID: 26784241 PMCID: PMC4730133 DOI: 10.3390/jcm5010008] [Citation(s) in RCA: 81] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2015] [Revised: 12/18/2015] [Accepted: 01/05/2016] [Indexed: 02/07/2023] Open
Abstract
Epithelial to mesenchymal transition (EMT) is a central regulatory program that is similar in many aspects to several steps of embryonic morphogenesis. In addition to its physiological role in tissue repair and wound healing, EMT contributes to chemo resistance, metastatic dissemination and fibrosis, amongst others. Classically, the morphological change from epithelial to mesenchymal phenotype is characterized by the appearance or loss of a group of proteins which have come to be recognized as markers of the EMT process. As with all proteins, these molecules are controlled at the transcriptional and translational level by transcription factors and microRNAs, respectively. A group of developmental transcription factors form the backbone of the EMT cascade and a large body of evidence shows that microRNAs are heavily involved in the successful coordination of mesenchymal transformation and vice versa, either by suppressing the expression of different groups of transcription factors, or otherwise acting as their functional mediators in orchestrating EMT. This article dissects the contribution of microRNAs to EMT and analyzes the molecular basis for their roles in this cellular process. Here, we emphasize their interaction with core transcription factors like the zinc finger enhancer (E)-box binding homeobox (ZEB), Snail and Twist families as well as some pluripotency transcription factors.
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Affiliation(s)
- Mohammed L Abba
- Department of Experimental Surgery, Center for Biomedicine and Medical Technology Mannheim (CBTM), Medical Faculty Mannheim, Ruprecht Karl University of Heidelberg, Ludolf-Krehl-Str. 6, 68135 Mannheim, Germany.
| | - Nitin Patil
- Department of Experimental Surgery, Center for Biomedicine and Medical Technology Mannheim (CBTM), Medical Faculty Mannheim, Ruprecht Karl University of Heidelberg, Ludolf-Krehl-Str. 6, 68135 Mannheim, Germany.
| | - Jörg Hendrik Leupold
- Department of Experimental Surgery, Center for Biomedicine and Medical Technology Mannheim (CBTM), Medical Faculty Mannheim, Ruprecht Karl University of Heidelberg, Ludolf-Krehl-Str. 6, 68135 Mannheim, Germany.
| | - Heike Allgayer
- Department of Experimental Surgery, Center for Biomedicine and Medical Technology Mannheim (CBTM), Medical Faculty Mannheim, Ruprecht Karl University of Heidelberg, Ludolf-Krehl-Str. 6, 68135 Mannheim, Germany.
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8
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Elias S, McGuire JR, Yu H, Humbert S. Huntingtin Is Required for Epithelial Polarity through RAB11A-Mediated Apical Trafficking of PAR3-aPKC. PLoS Biol 2015; 13:e1002142. [PMID: 25942483 PMCID: PMC4420272 DOI: 10.1371/journal.pbio.1002142] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2014] [Accepted: 03/24/2015] [Indexed: 11/19/2022] Open
Abstract
The establishment of apical-basolateral polarity is important for both normal development and disease, for example, during tumorigenesis and metastasis. During this process, polarity complexes are targeted to the apical surface by a RAB11A-dependent mechanism. Huntingtin (HTT), the protein that is mutated in Huntington disease, acts as a scaffold for molecular motors and promotes microtubule-based dynamics. Here, we investigated the role of HTT in apical polarity during the morphogenesis of the mouse mammary epithelium. We found that the depletion of HTT from luminal cells in vivo alters mouse ductal morphogenesis and lumen formation. HTT is required for the apical localization of PAR3-aPKC during epithelial morphogenesis in virgin, pregnant, and lactating mice. We show that HTT forms a complex with PAR3, aPKC, and RAB11A and ensures the microtubule-dependent apical vesicular translocation of PAR3-aPKC through RAB11A. We thus propose that HTT regulates polarized vesicular transport, lumen formation and mammary epithelial morphogenesis. Huntingtin—the protein that is aberrant in Huntington Disease—regulates apical vesicular trafficking to help establish apical-basolateral polarity during the development of mammary epithelia. In the adult mammary gland, tissue architecture is maintained through the regulation of the polarity of epithelial cells, which organize around a central cavity called the lumen. The mammary epithelium comprises a basal layer, which contains myoepithelial contractile cells and so-called mammary stem cells, and a luminal layer of cells organized around the lumen. The establishment of apical-basolateral polarity in luminal cells allows the separation of the apical and basolateral membranes and the maturation of cell–cell junctions. The protein complex composed of PAR3, PAR6, and aPKC regulates apical polarity in several tissues, including the mammary epithelium, and it is known that the loss of PAR3 and aPKC interferes with mammary gland development and promotes mammary tumor metastasis. RAB11A, a protein that regulates intracellular trafficking, coordinates apical translocation of PAR3-PAR6-aPKC. Huntingtin (HTT), the protein mutated in Huntington disease, modulates RAB11A activity and also regulates the microtubule-based vesicular trafficking in neurons. Using MCF10A, MDCK 2-D and 3-D cell cultures, and mouse models, we demonstrate here that HTT coordinates the apical vesicular trafficking of PAR3-PAR6-aPKC through RAB11A. We show that loss of HTT in luminal cells alters apical polarity, tissue architecture and the maturation of luminal cells during pregnancy and lactation in the mouse. Together, these findings uncover HTT-mediated vesicular trafficking as a new pathway in the establishment of epithelial apical polarity, with potential implications for health and disease.
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Affiliation(s)
- Salah Elias
- Institut Curie, Orsay, France
- CNRS UMR 3306, Orsay, France
- INSERM U1005, Orsay, France
| | - John Russel McGuire
- Institut Curie, Orsay, France
- CNRS UMR 3306, Orsay, France
- INSERM U1005, Orsay, France
| | - Hua Yu
- Institut Curie, Orsay, France
- CNRS UMR 3306, Orsay, France
- INSERM U1005, Orsay, France
| | - Sandrine Humbert
- Institut Curie, Orsay, France
- CNRS UMR 3306, Orsay, France
- INSERM U1005, Orsay, France
- Grenoble Institut des Neurosciences, University Grenoble Alpes, Grenoble, France
- INSERM U836, Grenoble, France
- * E-mail:
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9
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Tepass U. The apical polarity protein network in Drosophila epithelial cells: regulation of polarity, junctions, morphogenesis, cell growth, and survival. Annu Rev Cell Dev Biol 2012; 28:655-85. [PMID: 22881460 DOI: 10.1146/annurev-cellbio-092910-154033] [Citation(s) in RCA: 258] [Impact Index Per Article: 21.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Epithelial tissue formation and function requires the apical-basal polarization of individual epithelial cells. Apical polarity regulators (APRs) are an evolutionarily conserved group of key factors that govern polarity and several other aspects of epithelial differentiation. APRs compose a diverse set of molecules including a transmembrane protein (Crumbs), a serine/threonine kinase (aPKC), a lipid phosphatase (PTEN), a small GTPase (Cdc42), FERM domain proteins (Moesin, Yurt), and several adaptor or scaffolding proteins (Bazooka/Par3, Par6, Stardust, Patj). These proteins form a dynamic cooperative network that is engaged in negative-feedback regulation with basolateral polarity factors to set up the epithelial apical-basal axis. APRs support the formation of the apical junctional complex and the segregation of the junctional domain from the apical membrane. It is becoming increasingly clear that APRs interact with the cytoskeleton and vesicle trafficking machinery, regulate morphogenesis, and modulate epithelial cell growth and survival. Not surprisingly, APRs have multiple fundamental links to human diseases such as cancer and blindness.
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Affiliation(s)
- Ulrich Tepass
- Department of Cell and Systems Biology, University of Toronto, Toronto, Ontario M5S 3G5, Canada.
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10
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Van Campenhout CA, Eitelhuber A, Gloeckner CJ, Giallonardo P, Gegg M, Oller H, Grant SGN, Krappmann D, Ueffing M, Lickert H. Dlg3 trafficking and apical tight junction formation is regulated by nedd4 and nedd4-2 e3 ubiquitin ligases. Dev Cell 2011; 21:479-91. [PMID: 21920314 PMCID: PMC4452538 DOI: 10.1016/j.devcel.2011.08.003] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2010] [Revised: 05/24/2011] [Accepted: 08/01/2011] [Indexed: 01/01/2023]
Abstract
The Drosophila Discs large (Dlg) scaffolding protein acts as a tumor suppressor regulating basolateral epithelial polarity and proliferation. In mammals, four Dlg homologs have been identified; however, their functions in cell polarity remain poorly understood. Here, we demonstrate that the X-linked mental retardation gene product Dlg3 contributes to apical-basal polarity and epithelial junction formation in mouse organizer tissues, as well as to planar cell polarity in the inner ear. We purified complexes associated with Dlg3 in polarized epithelial cells, including proteins regulating directed trafficking and tight junction formation. Remarkably, of the four Dlg family members, Dlg3 exerts a distinct function by recruiting the ubiquitin ligases Nedd4 and Nedd4-2 through its PPxY motifs. We found that these interactions are required for Dlg3 monoubiquitination, apical membrane recruitment, and tight junction consolidation. Our findings reveal an unexpected evolutionary diversification of the vertebrate Dlg family in basolateral epithelium formation.
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11
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Humen MA, Pérez PF, Liévin-Le Moal V. Lipid raft-dependent adhesion of Giardia intestinalis trophozoites to a cultured human enterocyte-like Caco-2/TC7 cell monolayer leads to cytoskeleton-dependent functional injuries. Cell Microbiol 2011; 13:1683-702. [PMID: 21790940 DOI: 10.1111/j.1462-5822.2011.01647.x] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Gardia intestinalis, the aetiological agent of giardiasis, one of the most common intestinal diseases in both developing and developed countries, induces a loss of epithelial barrier function and functional injuries of the enterocyte by mechanisms that remain unknown. Three possible mechanisms have been proposed: (i) Giardia may directly alter the epithelial barrier after a close interaction between the trophozoite and polarized intestinal cells, (ii) intestinal functions may be altered by factors secreted by Giardia including an 'enterotoxin', proteinases and lectins, and (iii) based on mouse studies, a mechanism involving the intervention of activated T lymphocytes. We used fully differentiated cultured human intestinal Caco-2/TC7 cells forming a monolayer and expressing several polarized functions of enterocytes of small intestine to investigate the mechanisms by which G. intestinalis induces structural and functional alterations in the host intestinal epithelium. We first report that adhesion of G. intestinalis at the brush border of enterocyte-like cells involves the lipid raft membrane microdomains of the trophozoite. We report an adhesion-dependent disorganization of the apical F-actin cytoskeleton that, in turn, results in a dramatic loss of distribution of functional brush border-associated proteins, including sucrase-isomaltase (SI), dipeptidylpeptidase IV (DPP IV) and fructose transporter, GLUT5, and a decrease in sucrose enzyme activity in G. intestinalis-infected enterocyte-like cells. We observed that the G. intestinalis trophozoite promotes an adhesion-dependent decrease in transepithelial electrical resistance (TER) accompanied by a rearrangement of functional tight junction (TJ)-associated occludin, and delocalization of claudin-1. Finally, we found that whereas the occludin rearrangement induced by G. intestinalis was related to apical F-actin disorganization, the delocalization of claudin-1 was not.
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12
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El-Hashash AHK, Turcatel G, Al Alam D, Buckley S, Tokumitsu H, Bellusci S, Warburton D. Eya1 controls cell polarity, spindle orientation, cell fate and Notch signaling in distal embryonic lung epithelium. Development 2011; 138:1395-407. [PMID: 21385765 DOI: 10.1242/dev.058479] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Cell polarity, mitotic spindle orientation and asymmetric division play a crucial role in the self-renewal/differentiation of epithelial cells, yet little is known about these processes and the molecular programs that control them in embryonic lung distal epithelium. Herein, we provide the first evidence that embryonic lung distal epithelium is polarized with characteristic perpendicular cell divisions. Consistent with these findings, spindle orientation-regulatory proteins Insc, LGN (Gpsm2) and NuMA, and the cell fate determinant Numb are asymmetrically localized in embryonic lung distal epithelium. Interfering with the function of these proteins in vitro randomizes spindle orientation and changes cell fate. We further show that Eya1 protein regulates cell polarity, spindle orientation and the localization of Numb, which inhibits Notch signaling. Hence, Eya1 promotes both perpendicular division as well as Numb asymmetric segregation to one daughter in mitotic distal lung epithelium, probably by controlling aPKCζ phosphorylation. Thus, epithelial cell polarity and mitotic spindle orientation are defective after interfering with Eya1 function in vivo or in vitro. In addition, in Eya1(-/-) lungs, perpendicular division is not maintained and Numb is segregated to both daughter cells in mitotic epithelial cells, leading to inactivation of Notch signaling. As Notch signaling promotes progenitor cell identity at the expense of differentiated cell phenotypes, we test whether genetic activation of Notch could rescue the Eya1(-/-) lung phenotype, which is characterized by loss of epithelial progenitors, increased epithelial differentiation but reduced branching. Indeed, genetic activation of Notch partially rescues Eya1(-/-) lung epithelial defects. These findings uncover novel functions for Eya1 as a crucial regulator of the complex behavior of distal embryonic lung epithelium.
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Affiliation(s)
- Ahmed H K El-Hashash
- Developmental Biology and Regenerative Medicine Program, Saban Research Institute, Childrens Hospital Los Angeles, Keck School of Medicine of University of Southern California, 4661 Sunset Boulevard, Los Angeles, CA 90027, USA.
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13
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El-Hashash AH, Warburton D. Cell polarity and spindle orientation in the distal epithelium of embryonic lung. Dev Dyn 2011; 240:441-5. [PMID: 21246661 DOI: 10.1002/dvdy.22551] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
A proper balance between self-renewal and differentiation of lung-specific progenitors at the distal epithelial tips is absolutely required for normal lung morphogenesis. Cell polarity and mitotic spindle orientation play a critical role in the self-renewal/differentiation of epithelial cells and can impact normal physiological processes, including epithelial tissue branching and differentiation. Therefore, understanding the behavior of lung distal epithelial progenitors could identify innovative solutions to restoring normal lung morphogenesis. Yet little is known about cell polarity, spindle orientation, and segregation of cell fate determinant in the embryonic lung epithelium, which contains progenitor cells. Herein, we provide the first evidence that embryonic lung distal epithelium is polarized and highly mitotic with characteristic perpendicular cell divisions. Consistent with these findings, mInsc, LGN, and NuMA polarity proteins, which control spindle orientation, are asymmetrically localized in mitotic distal epithelial progenitors of embryonic lungs. Furthermore, the cell fate determinant Numb is asymmetrically distributed at the apical side of distal epithelial progenitors and segregated to one daughter cell in most mitotic cells. These findings provide evidence for polarity in distal epithelial progenitors of embryonic lungs and provide a framework for future translationally oriented studies in this area.
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Affiliation(s)
- Ahmed H El-Hashash
- Developmental Biology and Regenerative Medicine Program, Saban Research Institute, Children's Hospital Los Angeles, California, USA
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14
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Werth M, Walentin K, Aue A, Schönheit J, Wuebken A, Pode-Shakked N, Vilianovitch L, Erdmann B, Dekel B, Bader M, Barasch J, Rosenbauer F, Luft FC, Schmidt-Ott KM. The transcription factor grainyhead-like 2 regulates the molecular composition of the epithelial apical junctional complex. Development 2010; 137:3835-45. [PMID: 20978075 DOI: 10.1242/dev.055483] [Citation(s) in RCA: 152] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Differentiation of epithelial cells and morphogenesis of epithelial tubes or layers is closely linked with the establishment and remodeling of the apical junctional complex, which includes adherens junctions and tight junctions. Little is known about the transcriptional control of apical junctional complex components. Here, we show that the transcription factor grainyhead-like 2 (Grhl2), an epithelium-specific mammalian homolog of Drosophila Grainyhead, is essential for adequate expression of the adherens junction gene E-cadherin and the tight junction gene claudin 4 (Cldn4) in several types of epithelia, including gut endoderm, surface ectoderm and otic epithelium. We have generated Grhl2 mutant mice to demonstrate defective molecular composition of the apical junctional complex in these compartments that coincides with the occurrence of anterior and posterior neural tube defects. Mechanistically, we show that Grhl2 specifically associates with cis-regulatory elements localized at the Cldn4 core promoter and within intron 2 of the E-cadherin gene. Cldn4 promoter activity in epithelial cells is crucially dependent on the availability of Grhl2 and on the integrity of the Grhl2-associated cis-regulatory element. At the E-cadherin locus, the intronic Grhl2-associated cis-regulatory region contacts the promoter via chromatin looping, while loss of Grhl2 leads to a specific decrease of activating histone marks at the E-cadherin promoter. Together, our data provide evidence that Grhl2 acts as a target gene-associated transcriptional activator of apical junctional complex components and, thereby, crucially participates in epithelial differentiation.
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Affiliation(s)
- Max Werth
- Max-Delbrück Center for Molecular Medicine, Robert-Rössle-Strasse 10, 13125 Berlin, Germany
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15
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Abstract
BACKGROUND The ability to control uptake across the mucosa and protect from damage of harmful substances from the lumen is defined as intestinal barrier function. A disturbed barrier dysfunction has been described in many human diseases and animal models, for example, inflammatory bowel disease, irritable bowel syndrome, and intestinal hypersensitivity. In most diseases and models, alterations are seen both of the paracellular pathway, via the tight junctions, and of the transcellular routes, via different types of endocytosis. Recent studies of pathogenic mechanisms have demonstrated the important role of neuroimmune interaction with the epithelial cells in the regulation of barrier function. Neural impulses from extrinsic vagal and/or sympathetic efferent fibers or intrinsic enteric nerves influence mucosal barrier function via direct effects on epithelial cells or via interaction with immune cells. For example, by nerve-mediated activation by corticotropin-releasing hormone or cholinergic pathways, mucosal mast cells release a range of mediators with effects on transcellular, and/or paracellular permeability (for example, tryptase, TNF-alpha, nerve growth factor, and interleukins). PURPOSE In this review, we discuss current physiological and pathophysiological aspects of the intestinal barrier and, in particular, its regulation by neuroimmune factors.
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Affiliation(s)
- A V Keita
- Department of Clinical and Experimental Medicine, Division of Surgery and Clinical Oncology, Faculty of Health Science, University Hospital, Linköping, Sweden
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16
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The Drosophila Claudin Kune-kune is required for septate junction organization and tracheal tube size control. Genetics 2010; 185:831-9. [PMID: 20407131 DOI: 10.1534/genetics.110.114959] [Citation(s) in RCA: 85] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
The vertebrate tight junction is a critical claudin-based cell-cell junction that functions to prevent free paracellular diffusion between epithelial cells. In Drosophila, this barrier is provided by the septate junction, which, despite being ultrastructurally distinct from the vertebrate tight junction, also contains the claudin-family proteins Megatrachea and Sinuous. Here we identify a third Drosophila claudin, Kune-kune, that localizes to septate junctions and is required for junction organization and paracellular barrier function, but not for apical-basal polarity. In the tracheal system, septate junctions have a barrier-independent function that promotes lumenal secretion of Vermiform and Serpentine, extracellular matrix modifier proteins that are required to restrict tube length. As with Sinuous and Megatrachea, loss of Kune-kune prevents this secretion and results in overly elongated tubes. Embryos lacking all three characterized claudins have tracheal phenotypes similar to any single mutant, indicating that these claudins act in the same pathway controlling tracheal tube length. However, we find that there are distinct requirements for these claudins in epithelial septate junction formation. Megatrachea is predominantly required for correct localization of septate junction components, while Sinuous is predominantly required for maintaining normal levels of septate junction proteins. Kune-kune is required for both localization and levels. Double- and triple-mutant combinations of Sinuous and Megatrachea with Kune-kune resemble the Kune-kune single mutant, suggesting that Kune-kune has a more central role in septate junction formation than either Sinuous or Megatrachea.
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17
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Devaux J, Fykkolodziej B, Gow A. Claudin Proteins And Neuronal Function. CURRENT TOPICS IN MEMBRANES 2010; 65:229-253. [PMID: 25013353 DOI: 10.1016/s1063-5823(10)65010-7] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
The identification and characterization of the claudin family of tight junction (TJ) proteins in the late 1990s ushered in a new era for research into the molecular and cellular biology of intercellular junctions. Since that time, TJs have been studied in the contexts of many diseases including deafness, male infertility, cancer, bacterial invasion and liver and kidney disorders. In this review, we consider the role of claudins in the nervous system focusing on the mechanisms by which TJs in glial cells are involved in neuronal function. Electrophysiological evidence suggests that claudins may operate in the central nervous system (CNS) in a manner similar to polarized epithelia. We also evaluate hypotheses that TJs are the gatekeepers of an immune-privileged myelin compartment and that TJs emerged during evolution to form major adhesive forces within the myelin sheath. Finally, we consider the implications of CNS myelin TJs in the contexts of behavioral disorders (schizophrenia) and demyelinating/hypomyelinating diseases (multiple sclerosis and the leukodystrophies), and explore evidence of a possible mechanism governing affective disorder symptoms in patients with white matter abnormalities.
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Affiliation(s)
- Jérôme Devaux
- Département Signalisation Neuronale, CRN2M, UMR 6231, CNRS, Université de la Méditerranée-Université Paul Cézanne, IFR Jean Roche, Marseille, France
| | - Bozena Fykkolodziej
- Center for Molecular Medicine and Genetics, Wayne State University School of Medicine, Detroit, MI, 48201, USA
| | - Alexander Gow
- Center for Molecular Medicine and Genetics, Wayne State University School of Medicine, Detroit, MI, 48201, USA. ; Carman and Ann Adams Dept of Pediatrics, Wayne State University School of Medicine, Detroit, MI, 48201, USA. ; Dept of Neurology, Wayne State University School of Medicine, Detroit, MI, 48201, USA
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18
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Chang TL, Ito K, Ko TK, Liu Q, Salto-Tellez M, Yeoh KG, Fukamachi H, Ito Y. Claudin-1 has tumor suppressive activity and is a direct target of RUNX3 in gastric epithelial cells. Gastroenterology 2010; 138:255-65.e1-3. [PMID: 19706291 DOI: 10.1053/j.gastro.2009.08.044] [Citation(s) in RCA: 73] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/06/2009] [Revised: 08/03/2009] [Accepted: 08/10/2009] [Indexed: 12/13/2022]
Abstract
BACKGROUND & AIMS The transcription factor RUNX3 is a gastric tumor suppressor. Tumorigenic Runx3(-/-) gastric epithelial cells attach weakly to each other, compared with nontumorigenic Runx3(+/+) cells. We aimed to identify RUNX3 target genes that promote cell-cell contact to improve our understanding of RUNX3's role in suppressing gastric carcinogenesis. METHODS We compared gene expression profiles of Runx3(+/+) and Runx3(-/-) cells and observed down-regulation of genes associated with cell-cell adhesion in Runx3(-/-) cells. Reporter, mobility shift, and chromatin immunoprecipitation assays were used to examine the regulation of these genes by RUNX3. Tumorigenesis assays and immunohistological analyses of human gastric tumors were performed to confirm the role of the candidate genes in gastric tumor development. RESULTS Mobility shift and chromatin immunoprecipitation assays revealed that the promoter activity of the gene that encodes the tight junction protein claudin-1 was up-regulated via the binding of RUNX3 to the RUNX consensus sites. The tumorigenicity of gastric epithelial cells from Runx3(-/-) mice was significantly reduced by restoration of claudin-1 expression, whereas knockdown of claudin-1 increased the tumorigenicity of human gastric cancer cells. Concomitant expression of RUNX3 and claudin-1 was observed in human normal gastric epithelium and cancers. CONCLUSIONS The tight junction protein claudin-1 has gastric tumor suppressive activity and is a direct transcriptional target of RUNX3. Claudin-1 is down-regulated during the epithelial-mesenchymal transition; RUNX3 might therefore act as a tumor suppressor to antagonize the epithelial-mesenchymal transition.
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Affiliation(s)
- Ti Ling Chang
- Cancer Science Institute of Singapore, National University of Singapore, Singapore
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19
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Lynch AM, Hardin J. The assembly and maintenance of epithelial junctions in C. elegans. Front Biosci (Landmark Ed) 2009; 14:1414-32. [PMID: 19273138 DOI: 10.2741/3316] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
The epithelial tissues of the C. elegans embryo provide a "minimalist" system for examining phylogenetically conserved proteins that function in epithelial polarity and cell-cell adhesion in a multicellular organism. In this review, we provide an overview of three major molecular complexes at the apical surface of epithelial cells in the C. elegans embryo: the cadherin-catenin complex, the more basal DLG-1/AJM-1 complex, and the apical membrane domain, which shares similarities with the subapical complex in Drosophila and the PAR/aPKC complex in vertebrates. We discuss how the assembly of these complexes contributes to epithelial polarity and adhesion, proteins that act as effectors and/or regulators of each subdomain, and how these complexes functionally interact during embryonic morphogenesis. Although much remains to be clarified, significant progress has been made in recent years to clarify the role of these protein complexes in epithelial morphogenesis, and suggests that C. elegans will continue to be a fruitful system in which to elucidate functional roles for these proteins in a living embryo.
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Affiliation(s)
- Allison M Lynch
- Program in Genetics, University of Wisconsin-Madison, University of Wisconsin-Madison, Department of Zoology, University of Wisconsin-Madison, USA
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20
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Shook DR, Keller R. Epithelial type, ingression, blastopore architecture and the evolution of chordate mesoderm morphogenesis. JOURNAL OF EXPERIMENTAL ZOOLOGY PART B-MOLECULAR AND DEVELOPMENTAL EVOLUTION 2008; 310:85-110. [PMID: 18041055 DOI: 10.1002/jez.b.21198] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Chordate embryos show an evolutionary trend in the mechanisms they use to internalize presumptive mesoderm, relying predominantly on invagination in the basal chordates, varying combinations of involution and ingression in the anamniote vertebrates and reptiles, and predominantly on ingression in birds and mammals. This trend is associated with variations in epithelial type and changes in embryonic architecture as well as variations in the type of blastopore formed by an embryo. We also note the surprising conservation of the involution, during gastrulation, of at least a subset of the notochordal cells throughout the chordates, and suggest that this indicates a constraint on morphogenic evolution based on a functional linkage between architecture and patterning. Finally, we propose a model for the evolutionary transitions from gastrulation through a urodele amphibian-type blastopore to gastrulation through a primitive streak, as in chick or mouse.
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Affiliation(s)
- David R Shook
- Department of Biology, University of Virginia, Charlottesville, Virginia 22904-4328, USA.
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21
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Abstract
The function of a complex nervous system depends on an intricate interplay between neuronal and glial cell types. One of the many functions of glial cells is to provide an efficient insulation of the nervous system and thereby allowing a fine tuned homeostasis of ions and other small molecules. Here, we present a detailed cellular analysis of the glial cell complement constituting the blood-brain barrier in Drosophila. Using electron microscopic analysis and single cell-labeling experiments, we characterize different glial cell layers at the surface of the nervous system, the perineurial glial layer, the subperineurial glial layer, the wrapping glial cell layer, and a thick layer of extracellular matrix, the neural lamella. To test the functional roles of these sheaths we performed a series of dye penetration experiments in the nervous systems of wild-type and mutant embryos. Comparing the kinetics of uptake of different sized fluorescently labeled dyes in different mutants allowed to conclude that most of the barrier function is mediated by the septate junctions formed by the subperineurial cells, whereas the perineurial glial cell layer and the neural lamella contribute to barrier selectivity against much larger particles (i.e., the size of proteins). We further compare the requirements of different septate junction components for the integrity of the blood-brain barrier and provide evidence that two of the six Claudin-like proteins found in Drosophila are needed for normal blood-brain barrier function.
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22
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Nunes FD, Lopez LN, Lin HW, Davies C, Azevedo RB, Gow A, Kachar B. Distinct subdomain organization and molecular composition of a tight junction with adherens junction features. J Cell Sci 2006; 119:4819-27. [PMID: 17130295 DOI: 10.1242/jcs.03233] [Citation(s) in RCA: 84] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Most polarized epithelia constrain solute diffusion between luminal and interstitial compartments using tight junctions and generate mechanical strength using adherens junctions. These intercellular junctions are typically portrayed as incongruent macromolecular complexes with distinct protein components. Herein, we delineate the molecular composition and subdomain architecture of an intercellular junction between sensory and non-sensory cells of the inner ear. In this junction, claudins partition into claudin-14 and claudin-9/6 subdomains that are distinguishable by strand morphology, which contrasts with in vitro data that most claudins co-assemble into heteromeric strands. Surprisingly, canonical adherens junction proteins (p120ctn, α- and β-catenins) colocalize with the claudin-9/6 subdomain and recruit a dense cytoskeletal network. We also find that catenins colocalize with claudin-9 and claudin-6, but not claudin-14, in a heterologous system. Together, our data demonstrate that canonical tight junction and adherens junction proteins can be recruited to a single junction in which claudins partition into subdomains and form a novel hybrid tight junction with adherens junction organization.
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Affiliation(s)
- Fabio D Nunes
- Laboratory of Cellular Biology, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, MD 20892, USA
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23
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Lui WY, Lee WM. Regulation of junction dynamics in the testis--transcriptional and post-translational regulations of cell junction proteins. Mol Cell Endocrinol 2006; 250:25-35. [PMID: 16431017 DOI: 10.1016/j.mce.2005.12.021] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Cell junctions are the sites at which cells attach to the neighboring cells. They do not only maintain tissue integrity, their turnover also plays a crucial role in cell development and morphogenesis. In the testis, tight junctions and adherens junctions are dynamically remodeled to allow the movement of post-meiotic germ cells across the seminiferous epithelium and the timely release of spermatids into the tubular lumen. There is growing evidence that this dynamic remodeling of cell junctions is mediated by several mechanisms at the transcriptional and post-translational levels. This review summarizes what is known about the transcriptional regulation, ubiquitination and endocytosis that are involved in modulating junction dynamics in epithelial cells. It also highlights the recent findings on the regulation of junction dynamics in the testis and the specific areas that require further research for a thorough understanding of the role of junction remodeling in spermatogenesis. Understanding the junction dynamics in the seminiferous epithelium may unfold new targets for non-hormonal male contraceptive development.
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Affiliation(s)
- Wing-Yee Lui
- Department of Zoology, The University of Hong Kong, Pokfulam, Hong Kong, China
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24
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Johnson AH, Frierson HF, Zaika A, Powell SM, Roche J, Crowe S, Moskaluk CA, El-Rifai W. Expression of tight-junction protein claudin-7 is an early event in gastric tumorigenesis. THE AMERICAN JOURNAL OF PATHOLOGY 2005; 167:577-84. [PMID: 16049341 PMCID: PMC1603560 DOI: 10.1016/s0002-9440(10)62999-9] [Citation(s) in RCA: 87] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Trefoil factor-1 (Tff1) expression is remarkably down-regulated in nearly all human gastric cancers. Therefore, we used the Tff1 knockout mouse model to detect molecular changes in preneoplastic gastric dysplasia. Oligonucleotide microarray gene expression analysis of gastric dysplasia of Tff1-/- mice was compared to that of normal gastric mucosa of wild-type mice. The genes most overexpressed in Tff1-/- mice included claudin-7 (CLDN7), early growth response-1 (EGR1), and epithelial membrane protein-1 (EMP1). Quantitative real-time reverse transcriptase-polymerase chain reaction and immunohistochemistry showed that Cldn7 was overexpressed in all 10 Tff1-/- gastric dysplasia samples. Comparison with our serial analysis of gene expression database of human gastric cancer revealed similar deregulation in human gastric cancers. Quantitative real-time reverse transcriptase-polymerase chain reaction of human gastric adenocarcinoma samples indicated that, of these three genes, CLDN7 was the most frequently up-regulated gene. Using immunohistochemistry, both mouse and human gastric glands overexpressed Cldn7 in dysplastic but not surrounding normal glands. Cldn7 expression was observed in 30% of metaplasia, 80% of dysplasia, and 70% of gastric adenocarcinomas. Interestingly, 82% of human intestinal-type gastric adenocarcinomas expressed Cldn7 whereas diffuse-type gastric adenocarcinomas did not (P < 0.001). These results suggest that Cldn7 expression is an early event in gastric tumorigenesis that is maintained throughout tumor progression.
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Affiliation(s)
- Adam H Johnson
- Digestive Health Center of Excellence, University of Virginia Health System, P.O. Box 800708, Charlottesville, VA 22908-0708, USA
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25
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Schlüter H, Wepf R, Moll I, Franke WW. Sealing the live part of the skin: the integrated meshwork of desmosomes, tight junctions and curvilinear ridge structures in the cells of the uppermost granular layer of the human epidermis. Eur J Cell Biol 2005; 83:655-65. [PMID: 15679110 DOI: 10.1078/0171-9335-00434] [Citation(s) in RCA: 68] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
In the literature the question of whether a system structurally and functionally related to the barrier function of the tight junctions (TJs) of polarized epithelia exists in the epidermis has been and still is controversially discussed. We have systematically addressed this question in a study of the granular layer of fetal and adult human epidermis, combining different light and electron microscopic methods. We show that the lateral membranes of the cells of the stratum granulosum are connected by an extended subapical complex system integrating desmosomes and TJ structures identified as sites of close membrane-membrane contact and as regions of membrane-to-membrane apposition that in immunoelectron microscopy are positive for TJ marker proteins, notably occludin, indicative of an extended, probably continuous TJ barrier. In addition, we have noted in freeze-fractures of the apical membrane attaching this layer to the basalmost membrane of the stratum corneum an extended system integrating desmosomes with intramembraneous ridge configurations that appear as strands, circles, lariats or complex meshworks showing numerous continuities with the desmosomes. In some regions this system interconnecting desmosomes with curvilinear ridge structures occupies the major part of the plasma membrane. The molecular organizations and possible functional contributions of both structural systems positioned at the border between the living portion of the epidermis and the corneal layer are discussed, in particular in relation to the formation of a stable association between the two layers and of a barrier to the paracellular flow of molecules and particles. It is also discussed whether similar structures occur in other keratinizing stratified squamous epithelia, in squamous metaplasias and in tumors derived from such tissues.
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26
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Luk JM, Tong MK, Mok BW, Tam PC, Yeung WSB, Lee KF. Sp1 site is crucial for the mouse claudin-19 gene expression in the kidney cells. FEBS Lett 2005; 578:251-6. [PMID: 15589828 DOI: 10.1016/j.febslet.2004.11.010] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2004] [Revised: 10/25/2004] [Accepted: 11/02/2004] [Indexed: 12/11/2022]
Abstract
Members of the claudin family play important roles in the formation of tight junctions in the kidneys, liver and intestine. Claudin-19 (Cldn19), a newly identified member of this family, is highly expressed in the kidney of the mouse. To have a better understanding on mouse claudin-19 gene expression, a 0.9-kb DNA fragment containing the 5'-flanking region of the Cldn19 gene was isolated. DNA sequence comparison between the mouse and human Cldn19 promoter regions exhibited little homology. One transcription initiation site was located at 104 nucleotides upstream of the start codon (ATG) of the Cldn19 gene. The mouse claudin-19 promoter lacked typical CAAT or GC-box. Deletion constructs of the 0.9-kb DNA fragment were generated and fused to a promoterless luciferase (Luc) reporter plasmid. Transfection studies using various kidney cell lines (MDCK, mIMCD3 and HEK293) revealed that the minimal promoter fragment resided in the -39 to -108 region, which contained a number of binding sites for transcription factors including Sp1. Site-directed mutagenesis using specific oligo probes confirmed that Sp1 was crucial for Cldn19 transactivation in the three cell lines studied. Electromobility shift assay confirmed that the nuclear extracts of these cells bound to the Sp1 oligo derived from Cldn19 promoter, but not to the mutated Sp1 oligo probe. Moreover, this DNA-protein complex would be recognized by Sp1 antibody, indicating specific Sp1 binding. Collectively, our data suggest that Sp1 binds to the claudin-19 promoter region and is responsible for its expression in the kidney cell lines in vitro.
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Affiliation(s)
- John M Luk
- Department of Surgery, Hong Kong Jockey Club Clinical Research Centre, Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong SAR, China.
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27
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Abstract
Tight junctions form selective barriers that regulate paracellular transport across epithelia. A large family of tetraspanning cell-cell adhesion proteins called claudins create the barrier and regulate electrical resistance, size, and ionic charge selectivity. Study of inherited human claudin diseases and the outcome of the genetic manupulation of claudins in mice, Drosophila, and Caenorhabditis elegans are furthering our understanding of paracellular physiology.
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Affiliation(s)
- Christina M Van Itallie
- Department of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA.
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28
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Rinaudo P, Schultz RM. Effects of embryo culture on global pattern of gene expression in preimplantation mouse embryos. Reproduction 2004; 128:301-11. [PMID: 15333781 DOI: 10.1530/rep.1.00297] [Citation(s) in RCA: 211] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Culture of preimplantation embryos affects gene expression. The magnitude of the effect on the global pattern of gene expression, however, is not known. We compared global patterns of gene expression in blastocysts cultured from the one-cell stage in either Whitten's medium or KSOM + amino acids (KSOM/AA) with that of blastocysts that developed in vivo, using the Affymetrix MOE430A chip. The analysis revealed that expression of 114 genes was affected after culture in Whitten's medium, whereas only 29 genes were mis-expressed after culture in KSOM/AA. Expression Analysis Systematic Explorer was used to identify biological and molecular processes that are perturbed after culture and indicated that genes involved in protein synthesis, cell proliferation and transporter function were down-regulated after culture in Whitten's medium. A common set of genes involved in transporter function was also down-regulated after culture in KSOM/AA. These results provide insights as to why embryos develop better in KSOM/AA than in Whitten's medium, and highlight the power of microarray analysis to assess global patterns of gene expression.
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Affiliation(s)
- Paolo Rinaudo
- Department of Biology, University of Pennsylvania, Philadelphia, PA 19104, USA
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29
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Abstract
The fundamental functions of epithelia and endothelia in multicellular organisms are to separate compositionally distinct compartments and regulate the exchange of small solutes and other substances between them. Tight junctions (TJs) between adjacent cells constitute the barrier to the passage of ions and molecules through the paracellular pathway and function as a 'fence' within the plasma membrane to create and maintain apical and basolateral membrane domains. How TJs achieve this is only beginning to be understood. Recently identified components of TJs include the claudins, a family of four-transmembrane-span proteins that are prime candidates for molecules that function in TJ permeability. Their identification and characterization have provided new insight into the diversity of different TJs and heterogeneity of barrier functions in different epithelia and endothelia.
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Affiliation(s)
- Kursad Turksen
- Ottawa Health Research Institute, Ontario K1Y 4E9, Canada.
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30
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Anderson JM, Van Itallie CM, Fanning AS. Setting up a selective barrier at the apical junction complex. Curr Opin Cell Biol 2004; 16:140-5. [PMID: 15196556 DOI: 10.1016/j.ceb.2004.01.005] [Citation(s) in RCA: 168] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Across the animal kingdom the apical junction complex of epithelial cells creates both a permeability barrier and cell polarity. Although based on overlapping and evolutionarily conserved proteins, the cell-cell contacts of nematodes, flies and mammals appear to differ in morphology and functional organization. Emerging evidence shows that the selective pore-like properties of vertebrate and invertebrate barriers are created by the claudin family. Similarly, assembly of the barriers requires a conserved set of polarity-generating protein complexes, particularly the PAR protein complexes.
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Affiliation(s)
- James Melvin Anderson
- Department of Cell and Molecular Physiology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA.
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