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Song WX, Yu ZH, Ren XF, Chen JH, Chen X. Role of micronutrients in inflammatory bowel disease. Shijie Huaren Xiaohua Zazhi 2023; 31:711-731. [DOI: 10.11569/wcjd.v31.i17.711] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/08/2023] [Revised: 08/28/2023] [Accepted: 09/01/2023] [Indexed: 09/08/2023] Open
Abstract
Inflammatory bowel disease (IBD) is an autoimmune intestinal disease that includes ulcerative colitis, Crohn's disease, and indeterminate colitis. Patients with IBD are often at risk for malnutrition, including micronutrient deficiencies, due to dietary restrictions and poor intestinal absorption. Micronutrients, including vitamins and minerals, play an important role in the human body's metabolism and maintenance of tissue functions. This article reviews the role of micronutrients in IBD. Micronutrients can affect the occurrence and progression of IBD by regulating immunity, intestinal flora, oxidative stress, intestinal barrier function, and other aspects. Monitoring and timely supplementation of micronutrients are important to delay progression and improve clinical symptoms in IBD patients.
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Affiliation(s)
- Wen-Xuan Song
- Department of Gastroenterology and Hepatology, Tianjin Medical University General Hospital, Tianjin 300052, China
| | - Zi-Han Yu
- Department of Gastroenterology and Hepatology, Tianjin Medical University General Hospital, Tianjin 300052, China
| | - Xiang-Feng Ren
- Department of Gastroenterology and Hepatology, Tianjin Medical University General Hospital, Tianjin 300052, China
| | - Ji-Hua Chen
- Department of Gastroenterology and Hepatology, Tianjin Medical University General Hospital, Tianjin 300052, China
| | - Xin Chen
- Department of Gastroenterology and Hepatology, Tianjin Medical University General Hospital, Tianjin 300052, China
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Inulin supplementation ameliorates hyperuricemia and modulates gut microbiota in Uox-knockout mice. Eur J Nutr 2020; 60:2217-2230. [PMID: 33104864 PMCID: PMC8137640 DOI: 10.1007/s00394-020-02414-x] [Citation(s) in RCA: 57] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2020] [Accepted: 10/13/2020] [Indexed: 12/15/2022]
Abstract
Purpose Inulin is a type of fermentable dietary fiber, which is non-digestible, and can improve metabolic function by modulating intestinal microbiota. This study aimed to evaluate the role of inulin in hyperuricemia and microbial composition of the gut microbiota in a mouse model of hyperuricemia established through knockout of Uox (urate oxidase) gene. Methods KO (Uox-knockout) and WT (wild-type) mice were given inulin or saline by gavage for 7 weeks. The effect of inulin to combat hyperuricemia was determined by assessing the changes in serum UA (uric acid) levels, inflammatory parameters, epithelial barrier integrity, fecal microbiota alterations, and SCFA (short-chain fatty acid) concentrations in KO mice. Results Inulin supplementation can effectively alleviate hyperuricemia, increase the expressions of ABCG2 in intestine, and downregulate expression and activity of hepatic XOD (xanthine oxidase) in KO mice. It was revealed that the levels of inflammatory cytokines and the LPS (lipopolysaccharide) were remarkably higher in the KO group than those in the WT group, indicating systemic inflammation of hyperuricemic mice, but inulin treatment ameliorated inflammation in KO mice. Besides, inulin treatment repaired the intestinal epithelial barrier as evidenced by increased levels of intestinal TJ (tight junction) proteins [ZO-1 (zonula occludens-1) and occluding] in KO mice. Moreover, serum levels of uremic toxins, including IS (indoxyl sulfate) and PCS (p-cresol sulfate), were reduced in inulin-treated KO mice. Further investigation unveiled that inulin supplementation enhanced microbial diversity and raised the relative abundance of beneficial bacteria, involving SCFAs-producing bacteria (e.g., Akkermansia and Ruminococcus). Additionally, inulin treatment increased the production of gut microbiota-derived SCFAs (acetate, propionate and butyrate concentrations) in KO mice, which was positively correlated with the effectiveness of hyperuricemia relief. Conclusions Our findings showed that inulin may be a promising therapeutic candidate for the treatment of hyperuricemia. Moreover, alleviation of hyperuricemia by inulin supplementation was, at least, partially conciliated by modulation of gut microbiota and its metabolites. Electronic supplementary material The online version of this article (10.1007/s00394-020-02414-x) contains supplementary material, which is available to authorized users.
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Rawat M, Nighot M, Al-Sadi R, Gupta Y, Viszwapriya D, Yochum G, Koltun W, Ma TY. IL1B Increases Intestinal Tight Junction Permeability by Up-regulation of MIR200C-3p, Which Degrades Occludin mRNA. Gastroenterology 2020; 159:1375-1389. [PMID: 32569770 DOI: 10.1053/j.gastro.2020.06.038] [Citation(s) in RCA: 101] [Impact Index Per Article: 25.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/10/2019] [Revised: 05/28/2020] [Accepted: 06/17/2020] [Indexed: 12/21/2022]
Abstract
BACKGROUND & AIMS Defects in the epithelial tight junction (TJ) barrier contribute to development of intestinal inflammation associated with diseases. Interleukin 1 beta (IL1B) increases intestinal permeability in mice. We investigated microRNAs that are regulated by IL1B and their effects on expression of TJ proteins and intestinal permeability. METHODS We used Targetscan to identify microRNAs that would bind the 3' untranslated region (3'UTR) of occludin mRNA; regions that interacted with microRNAs were predicted using the V-fold server and Assemble2, and 3-dimensional models were created using UCSF Chimera linked with Assemble2. Caco-2 cells were transfected with vectors that express microRNAs, analyzed by immunoblots and real-time polymerase chain reaction (PCR), and grown as monolayers; permeability in response to IL1B was assessed with the marker inulin. Male C57BL/6 mice were given intraperitoneal injections of IL1B and intestinal recycling perfusion was measured; some mice were given dextran sodium sulfate to induce colitis and/or gavage with an antagonist to MIR200C-3p (antagomiR-200C) or the nonspecific antagomiR (control). Intestinal tissues were collected from mice and analyzed by histology and real-time PCR; enterocytes were isolated by laser capture microdissection. We also analyzed colon tissues and organoids from patients with and without ulcerative colitis. RESULTS Incubation of Caco-2 monolayers with IL1B increased TJ permeability and reduced levels of occludin protein and mRNA without affecting the expression of other transmembrane TJ proteins. Targetscan identified MIR122, MIR200B-3p, and MIR200C-3p, as miRNAs that might bind to the occludin 3'UTR. MIR200C-3p was rapidly increased in Caco-2 cells incubated with IL1B; the antagomiR-200c prevented the IL1B-induced decrease in occludin mRNA and protein and reduced TJ permeability. Administration of IL1B to mice increased small intestinal TJ permeability, compared with mice given vehicle; enterocytes isolated from mice given IL1B had increased expression of MIR200C-3p and decreased levels of occludin messenger RNA (mRNA) and protein. Intestinal tissues from mice with colitis had increased levels of IL1B mRNA and MIR200C-3p and decreased levels of occludin mRNA; gavage of mice with antagomiR-200C reduced levels of MIR200C-3p and prevented the decrease in occludin mRNA and the increase in colonic permeability. Colon tissues and organoids from patients with ulcerative colitis had increased levels of IL1B mRNA and MIR200C-3p compared with healthy controls. Using 3-dimensional molecular modeling and mutational analyses, we identified the nucleotide bases in the occluding mRNA 3'UTR that interact with MIR200C-3p. CONCLUSIONS Intestine tissues from patients with ulcerative colitis and mice with colitis have increased levels of IL1B mRNA and MIR200C-3p, which reduces expression of occludin by enterocytes and thereby increases TJ permeability. Three-dimensional modeling of the interaction between MIR200C-3p and the occludin mRNA 3'UTR identified sites of interaction. The antagomiR-200C prevents the decrease in occludin in enterocytes and intestine tissues of mice with colitis, maintaining the TJ barrier.
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Affiliation(s)
- Manmeet Rawat
- Department of Internal Medicine, University of New Mexico School of Medicine, Albuquerque, New Mexico
| | - Meghali Nighot
- Penn State Health Milton S. Hershey Medical Center, Hershey, Pennsylvania
| | - Rana Al-Sadi
- Penn State Health Milton S. Hershey Medical Center, Hershey, Pennsylvania
| | - Yash Gupta
- Department of Medicine, Loyola University Medical Center, Maywood, Illinois
| | | | - Gregory Yochum
- Division of Colon and Rectal Surgery, Department of Surgery, Pennsylvania State University, College of Medicine, Hershey, Pennsylvania; Department of Biochemistry and Molecular Biology, Pennsylvania State University, College of Medicine, Hershey, Pennsylvania
| | - Walter Koltun
- Division of Colon and Rectal Surgery, Department of Surgery, Pennsylvania State University, College of Medicine, Hershey, Pennsylvania
| | - Thomas Y Ma
- Department of Internal Medicine, University of New Mexico School of Medicine, Albuquerque, New Mexico; Penn State Health Milton S. Hershey Medical Center, Hershey, Pennsylvania.
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MLKL trafficking and accumulation at the plasma membrane control the kinetics and threshold for necroptosis. Nat Commun 2020; 11:3151. [PMID: 32561730 PMCID: PMC7305196 DOI: 10.1038/s41467-020-16887-1] [Citation(s) in RCA: 175] [Impact Index Per Article: 43.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2020] [Accepted: 05/27/2020] [Indexed: 12/19/2022] Open
Abstract
Mixed lineage kinase domain-like (MLKL) is the terminal protein in the pro-inflammatory necroptotic cell death program. RIPK3-mediated phosphorylation is thought to initiate MLKL oligomerization, membrane translocation and membrane disruption, although the precise choreography of events is incompletely understood. Here, we use single-cell imaging approaches to map the chronology of endogenous human MLKL activation during necroptosis. During the effector phase of necroptosis, we observe that phosphorylated MLKL assembles into higher order species on presumed cytoplasmic necrosomes. Subsequently, MLKL co-traffics with tight junction proteins to the cell periphery via Golgi-microtubule-actin-dependent mechanisms. MLKL and tight junction proteins then steadily co-accumulate at the plasma membrane as heterogeneous micron-sized hotspots. Our studies identify MLKL trafficking and plasma membrane accumulation as crucial necroptosis checkpoints. Furthermore, the accumulation of phosphorylated MLKL at intercellular junctions accelerates necroptosis between neighbouring cells, which may be relevant to inflammatory bowel disease and other necroptosis-mediated enteropathies. Mixed lineage kinase domain-like (MLKL) is the terminal protein in the pro-inflammatory necroptotic cell death program. Here the authors show that MLKL trafficking and plasma membrane accumulation are crucial necroptosis checkpoints, and that accumulation of phosphorylated MLKL at intercellular junctions promotes necroptosis.
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Abstract
Epithelial cells form highly organized polarized sheets with characteristic cell morphologies and tissue architecture. Cell–cell adhesion and intercellular communication are prerequisites of such cohesive sheets of cells, and cell connectivity is mediated through several junctional assemblies, namely desmosomes, adherens, tight and gap junctions. These cell–cell junctions form signalling hubs that not only mediate cell–cell adhesion but impact on multiple aspects of cell behaviour, helping to coordinate epithelial cell shape, polarity and function. This review will focus on the tight and adherens junctions, constituents of the apical junctional complex, and aims to provide a comprehensive overview of the complex signalling that underlies junction assembly, integrity and plasticity.
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Affiliation(s)
- Alexandra D Rusu
- School of Life Sciences, University of Nottingham, Nottingham NG7 2UH, UK
| | - Marios Georgiou
- School of Life Sciences, University of Nottingham, Nottingham NG7 2UH, UK
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Trapani V, Petito V, Di Agostini A, Arduini D, Hamersma W, Pietropaolo G, Luongo F, Arena V, Stigliano E, Lopetuso LR, Gasbarrini A, Wolf FI, Scaldaferri F. Dietary Magnesium Alleviates Experimental Murine Colitis Through Upregulation of the Transient Receptor Potential Melastatin 6 Channel. Inflamm Bowel Dis 2018; 24:2198-2210. [PMID: 29788266 DOI: 10.1093/ibd/izy186] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/22/2017] [Indexed: 12/11/2022]
Abstract
BACKGROUND Magnesium (Mg) is essential for human health and is absorbed mainly in the intestine. In view of the likely occurrence of an Mg deficit in inflammatory bowel disease (IBD) and the documented role of Mg in modulating inflammation, the present study addresses whether Mg availability can affect the onset and progression of intestinal inflammation. METHODS To study the correlation between Mg status and disease activity, we measured magnesemia by atomic absorption spectroscopy in a cohort of IBD patients. The effects of dietary Mg modulation were assessed in a murine model of dextran sodium sulfate (DSS)-induced colitis by monitoring magnesemia, weight, fecal occult blood, diarrhea, colon length, and histology. Expression of the transient receptor potential melastatin (TRPM) 6 channel was assessed by real-time reverse transcription polymerase chain reaction and immunohistochemistry in murine colon tissues. The effect of Mg on epithelial barrier formation/repair was evaluated in human colon cell lines. RESULTS Inflammatory bowel disease patients presented with a substantial Mg deficit, and serum Mg levels were inversely correlated with disease activity. In mice, an Mg-deficient diet caused hypomagnesemia and aggravated DSS-induced colitis. Colitis severely compromised intestinal Mg2+ absorption due to mucosal damage and reduction in TRPM6 expression, but Mg supplementation resulted in better restoration of mucosal integrity and channel expression. CONCLUSIONS Our results highlight the importance of evaluating and correcting magnesemia in IBD patients. The murine model suggests that Mg supplementation may represent a safe and cost-effective strategy to reduce inflammation and restore normal mucosal function.
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Affiliation(s)
- Valentina Trapani
- Istituto di Patologia Generale, Fondazione Policlinico Universitario "Agostino Gemelli," Rome, Italy
| | - Valentina Petito
- Polo di Scienze Gastroenterologiche ed Endocrino-Metaboliche, Area Gastroenterologia, Medicina Interna, Gastroenterologia e Malattie del Fegato, Fondazione Policlinico Universitario "Agostino Gemelli," Rome, Italy
| | - Angelica Di Agostini
- Polo di Scienze Gastroenterologiche ed Endocrino-Metaboliche, Area Gastroenterologia, Medicina Interna, Gastroenterologia e Malattie del Fegato, Fondazione Policlinico Universitario "Agostino Gemelli," Rome, Italy
| | - Daniela Arduini
- Istituto di Patologia Generale, Fondazione Policlinico Universitario "Agostino Gemelli," Rome, Italy
| | - Willem Hamersma
- Istituto di Patologia Generale, Fondazione Policlinico Universitario "Agostino Gemelli," Rome, Italy
| | - Giuseppe Pietropaolo
- Istituto di Patologia Generale, Fondazione Policlinico Universitario "Agostino Gemelli," Rome, Italy
| | - Francesca Luongo
- Istituto di Patologia Generale, Fondazione Policlinico Universitario "Agostino Gemelli," Rome, Italy
| | - Vincenzo Arena
- Istituto di Anatomia Patologica, Università Cattolica del Sacro Cuore, Fondazione Policlinico Universitario "Agostino Gemelli," Rome, Italy
| | - Egidio Stigliano
- Istituto di Anatomia Patologica, Università Cattolica del Sacro Cuore, Fondazione Policlinico Universitario "Agostino Gemelli," Rome, Italy
| | - Loris R Lopetuso
- Polo di Scienze Gastroenterologiche ed Endocrino-Metaboliche, Area Gastroenterologia, Medicina Interna, Gastroenterologia e Malattie del Fegato, Fondazione Policlinico Universitario "Agostino Gemelli," Rome, Italy
| | - Antonio Gasbarrini
- Polo di Scienze Gastroenterologiche ed Endocrino-Metaboliche, Area Gastroenterologia, Medicina Interna, Gastroenterologia e Malattie del Fegato, Fondazione Policlinico Universitario "Agostino Gemelli," Rome, Italy
| | - Federica I Wolf
- Istituto di Patologia Generale, Fondazione Policlinico Universitario "Agostino Gemelli," Rome, Italy
| | - Franco Scaldaferri
- Polo di Scienze Gastroenterologiche ed Endocrino-Metaboliche, Area Gastroenterologia, Medicina Interna, Gastroenterologia e Malattie del Fegato, Fondazione Policlinico Universitario "Agostino Gemelli," Rome, Italy
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Blood-brain barrier regulation in psychiatric disorders. Neurosci Lett 2018; 726:133664. [PMID: 29966749 DOI: 10.1016/j.neulet.2018.06.033] [Citation(s) in RCA: 148] [Impact Index Per Article: 24.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2018] [Accepted: 06/18/2018] [Indexed: 02/07/2023]
Abstract
The blood-brain barrier (BBB) is a dynamic interface between the peripheral blood supply and the cerebral parenchyma, controlling the transport of material to and from the brain. Tight junctions between the endothelial cells of the cerebral microvasculature limit the passage of large, negatively charged molecules via paracellular diffusion whereas transcellular transportation across the endothelial cell is controlled by a number of mechanisms including transporter proteins, endocytosis, and diffusion. Here, we review the evidence that perturbation of these processes may underlie the development of psychiatric disorders including schizophrenia, autism spectrum disorder (ASD), and affective disorders. Increased permeability of the BBB appears to be a common factor in these disorders, leading to increased infiltration of peripheral material into the brain culminating in neuroinflammation and oxidative stress. However, although there is no common mechanism underpinning BBB dysfunction even within each particular disorder, the tight junction protein claudin-5 may be a clinically relevant target given that both clinical and pre-clinical research has linked it to schizophrenia, ASD, and depression. Additionally, we discuss the clinical significance of the BBB in diagnosis (genetic markers, dynamic contrast-enhanced-magnetic resonance imaging, and blood biomarkers) and in treatment (drug delivery).
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Hsu CY, Lecland N, Pendaries V, Viodé C, Redoulès D, Paul C, Merdes A, Simon M, Bierkamp C. Stabilization of microtubules restores barrier function after cytokine-induced defects in reconstructed human epidermis. J Dermatol Sci 2018; 91:87-96. [PMID: 29691121 DOI: 10.1016/j.jdermsci.2018.04.008] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2017] [Revised: 03/21/2018] [Accepted: 04/10/2018] [Indexed: 12/21/2022]
Abstract
BACKGROUND A variety of human skin disorders is characterized by defects in the epidermal barrier, leading to dehydration, itchiness, and rashes. Previously published literature suggests that microtubule stabilization at the cortex of differentiating keratinocytes is necessary for the formation of the epidermal barrier. OBJECTIVES We tested whether stabilization of microtubules with paclitaxel or epothilone B can repair barrier defects that were experimentally induced in three-dimensional culture models of epidermis. METHODS We established two models of defective epidermis in vitro, using three-dimensional cultures of primary human keratinocytes on filter supports: immature reconstructed human epidermis (RHE), and RHE that was compromised by treatment with inflammatory cytokines, the latter mimicking defects seen in atopic dermatitis. RESULTS Both paclitaxel and epothilone B promoted keratinocyte differentiation, accumulation of junctional proteins at the cell cortex, and the early appearance of lamellar bodies in immature RHE, whereas destabilization of microtubules by nocodazole had the reverse effect. Moreover, stabilization of microtubules rescued the barrier after cytokine treatment. The rescued barrier function correlated with the restoration of filaggrin and loricrin protein levels, the cortical accumulation of junctional proteins (E-cadherin, β-catenin, and claudin-1), and with the secretion of lamellar bodies. CONCLUSIONS Our data suggest that the microtubule network is important for the formation of the epidermis, and that stabilization of microtubules promotes barrier formation. Microtubule stabilization may support regeneration of damaged skin, by restoring or improving the barrier.
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Affiliation(s)
- Chiung-Yueh Hsu
- Centre de Biologie du Développement, Université Paul Sabatier/CNRS, 31062, Toulouse, France
| | - Nicolas Lecland
- Centre de Biologie du Développement, Université Paul Sabatier/CNRS, 31062, Toulouse, France
| | - Valérie Pendaries
- INSERM-Université Paul Sabatier U1056, UDEAR, CHU Purpan, 31059, Toulouse, France
| | - Cécile Viodé
- Pierre Fabre Dermo-Cosmétique, 3 Avenue Hubert Curien, 31100, Toulouse, France
| | - Daniel Redoulès
- Pierre Fabre Dermo-Cosmétique, 3 Avenue Hubert Curien, 31100, Toulouse, France
| | - Carle Paul
- INSERM-Université Paul Sabatier U1056, UDEAR, CHU Purpan, 31059, Toulouse, France; Dermatologie, Hôpital Larrey, Centre Hospitalier Universitaire de Toulouse, 31059, Toulouse, France
| | - Andreas Merdes
- Centre de Biologie du Développement, Université Paul Sabatier/CNRS, 31062, Toulouse, France.
| | - Michel Simon
- INSERM-Université Paul Sabatier U1056, UDEAR, CHU Purpan, 31059, Toulouse, France.
| | - Christiane Bierkamp
- Centre de Biologie du Développement, Université Paul Sabatier/CNRS, 31062, Toulouse, France.
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Van Itallie CM, Anderson JM. Architecture of tight junctions and principles of molecular composition. Semin Cell Dev Biol 2014; 36:157-65. [PMID: 25171873 DOI: 10.1016/j.semcdb.2014.08.011] [Citation(s) in RCA: 349] [Impact Index Per Article: 34.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2014] [Revised: 08/15/2014] [Accepted: 08/19/2014] [Indexed: 12/11/2022]
Abstract
The tight junction creates an intercellular barrier limiting paracellular movement of solutes and material across epithelia. Currently many proteins have been identified as components of the tight junction and understanding their architectural organization and interactions is critical to understanding the biology of the barrier. In general the architecture can be conceptualized into compartments with the transmembrane barrier proteins (claudins, occludin, JAM-A, etc.), linked to peripheral scaffolding proteins (such as ZO-1, afadin, MAGI1, etc.) which are in turned linked to actin and microtubules through numerous linkers (cingulin, myosins, protein 4.1, etc.). Within this complex network are associated many signaling proteins that affect the barrier and broader cell functions. The PDZ domain is a commonly used motif to specifically link individual junction protein pairs. Here we review some of the key proteins defining the tight junction and general themes of their organization with the perspective that much will be learned about function by characterizing the detailed architecture and subcompartments within the junction.
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Affiliation(s)
- Christina M Van Itallie
- The Laboratory of Tight Junction Structure and Function, National Heart, Lung, and Blood Institute, National Institutes of Health, Building 50, Room 4525, 50 South Drive, Bethesda, MD 20892, USA.
| | - James M Anderson
- The Laboratory of Tight Junction Structure and Function, National Heart, Lung, and Blood Institute, National Institutes of Health, Building 50, Room 4525, 50 South Drive, Bethesda, MD 20892, USA.
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Glotfelty LG, Zahs A, Hodges K, Shan K, Alto NM, Hecht GA. Enteropathogenic E. coli effectors EspG1/G2 disrupt microtubules, contribute to tight junction perturbation and inhibit restoration. Cell Microbiol 2014; 16:1767-83. [PMID: 24948117 DOI: 10.1111/cmi.12323] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2013] [Revised: 05/20/2014] [Accepted: 06/05/2014] [Indexed: 12/14/2022]
Abstract
Enteropathogenic Escherichia coli (EPEC) uses a type 3 secretion system to transfer effector proteins into the host intestinal epithelial cell. Several effector molecules contribute to tight junction disruption including EspG1 and its homologue EspG2 via a mechanism thought to involve microtubule destruction. The aim of this study was to investigate the contribution of EspG-mediated microtubule disruption to TJ perturbation. We demonstrate that wild type EPEC infection disassembles microtubules and induces the progressive movement of occludin away from the membrane and into the cytosol. Deletion of espG1/G2 attenuates both of these phenotypes. In addition, EPEC infection impedes barrier recovery from calcium switch, suggesting that inhibition of TJ restoration, not merely disruption, prolongs barrier loss. TJs recover more rapidly following infection with ΔespG1/G2 than with wild type EPEC, demonstrating that EspG1/G2 perpetuate barrier loss. Although EspG regulates ADP-ribosylation factor (ARF) and p21-activated kinase (PAK), these activities are not necessary for microtubule destruction or perturbation of TJ structure and function. These data strongly support a role for EspG1/G2 and its associated effects on microtubules in delaying the recovery of damaged tight junctions caused by EPEC infection.
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Affiliation(s)
- Lila G Glotfelty
- Department of Microbiology & Immunology, University of Illinois at Chicago, 835 S. Wolcott, (M/C 790), Chicago, IL, 60612, USA
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Glotfelty LG, Zahs A, Iancu C, Shen L, Hecht GA. Microtubules are required for efficient epithelial tight junction homeostasis and restoration. Am J Physiol Cell Physiol 2014; 307:C245-54. [PMID: 24920678 DOI: 10.1152/ajpcell.00336.2013] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Epithelial tight junctions are critical for creating a barrier yet allowing paracellular transport. Although it is well established that the actin cytoskeleton is critical for preserving the dynamic organization of the tight junction and maintaining normal tight junction protein recycling, contributions of microtubules to tight junction organization and function remain undefined. The aim of this study is to determine the role of microtubules in tight junction homeostasis and restoration. Our data demonstrate that occludin traffics on microtubules and that microtubule disruption perturbs tight junction structure and function. Microtubules are also shown to be required for restoring barrier function following Ca(2+) chelation and repletion. These processes are mediated by proteins participating in microtubule minus-end-directed trafficking but not plus-end-directed trafficking. These studies show that microtubules participate in the preservation of epithelial tight junction structure and function and play a vital role in tight junction restoration, thus expanding our understanding of the regulation of tight junction physiology.
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Affiliation(s)
- Lila G Glotfelty
- Department of Microbiology and Immunology, University of Illinois at Chicago, Chicago, Illinois
| | - Anita Zahs
- Departments of Medicine and Microbiology and Immunology, Loyola University Chicago, Maywood, Illinois
| | - Catalin Iancu
- Departments of Medicine and Microbiology and Immunology, Loyola University Chicago, Maywood, Illinois
| | - Le Shen
- University of Chicago, Chicago, Illinois
| | - Gail A Hecht
- Departments of Medicine and Microbiology and Immunology, Loyola University Chicago, Maywood, Illinois; Edward Hines Jr. VA Hospital, Hines, Illinois
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Ren WY, Wu KF, Li X, Luo M, Liu HC, Zhang SC, Hu Y. Age-related changes in small intestinal mucosa epithelium architecture and epithelial tight junction in rat models. Aging Clin Exp Res 2014; 26:183-91. [PMID: 24243034 DOI: 10.1007/s40520-013-0148-0] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2013] [Accepted: 09/18/2013] [Indexed: 12/29/2022]
Abstract
BACKGROUND AND AIMS Functions of the intestinal mucosal barrier are often impaired in the elderly and are closely associated with many age-related diseases. However, mechanisms by which aging influences intestinal barrier function still remain unclear. The aim of this study was to investigate age-related changes in small intestinal morphology, bacteria contents and expression of epithelial tight junction (TJ) proteins. METHODS Thirty Sprague-Dawley rats were divided into groups: young (3 months), adult (12 months), and old (24 months). The small intestinal mucosal architecture and TJ of intestinal epithelial cells were examined by light microscopy and transmission electron microscopy. Jejunum and cecum contents were cultured to identify and measure bacterial species. mRNA expression of Zonula occludens-1 (ZO-1) and occludin were measured by semi-quantitative RT-PCR. Protein expression of ZO-1 and occludin were detected by immunohistochemistry and Western blot. RESULTS Normal ileum villi, which were thick and regularly arranged, though increasingly scattered and atrophic in character with shorter and narrower dimensions (P < 0.01), were observed in old rats, along with an elevated number of Gram-positive and Gram-negative bacteria in the jejunum. The TJs of intestinal epithelial cells, as detected by transmission electron microscopy, were wider and discontinuous in old rats. Age-induced down-regulation of mRNA expression and decreased protein expression of ZO-1 and occludin were observed in the ileum (P < 0.01). CONCLUSIONS Our study indicated that age-related intestinal barrier dysfunction may be associated with mucosal atrophy, damages to TJ structure, increased small intestine bacteria counts, and decreased epithelial TJ protein.
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Qasim M, Rahman H, Ahmed R, Oellerich M, Asif AR. Mycophenolic acid mediated disruption of the intestinal epithelial tight junctions. Exp Cell Res 2014; 322:277-89. [PMID: 24509232 DOI: 10.1016/j.yexcr.2014.01.021] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2013] [Revised: 12/21/2013] [Accepted: 01/21/2014] [Indexed: 12/12/2022]
Abstract
Gastrointestinal toxicity is a common adverse effect of mycophenolic acid (MPA) treatment in organ transplant patients, through poorly understood mechanisms. Phosphorylation of myosin light chain 2 (MLC2) is associated with epithelial tight junction (TJ) modulation which leads to defective epithelial barrier function, and has been implicated in GI diseases. The aim of this study was to investigate whether MPA could induce epithelial barrier permeability via MLC2 regulation. Caco-2 monolayers were exposed to therapeutic concentrations of MPA, and MLC2 and myosin light chain kinase (MLCK) expression were analyzed using PCR and immunoblotting. Epithelial cell permeability was assessed by measuring transepithelial resistance (TER) and the flux of paracellular permeability marker FITC-dextran across the epithelial monolayers. MPA increased the expression of MLC2 and MLCK at both the transcriptional and translational levels. In addition, the amount of phosphorylated MLC2 was increased after MPA treatment. Confocal immunofluorescence analysis showed redistribution of TJ proteins (ZO-1 and occludin) after MPA treatment. This MPA mediated TJ disruption was not due to apoptosis or cell death. Additionally ML-7, a specific inhibitor of MLCK was able to reverse both the MPA mediated decrease in TER and the increase in FITC-dextran influx, suggesting a modulating role of MPA on epithelial barrier permeability via MLCK activity. These results suggest that MPA induced alterations in MLC2 phosphorylation and may have a role in the patho-physiology of intestinal epithelial barrier disruption and may be responsible for the adverse effects (GI toxicity) of MPA on the intestine.
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Affiliation(s)
- Muhammad Qasim
- Institute of Clinical Chemistry/UMG-Laboratories, University Medical Centre, Robert Koch Strasse 40, 37075 Goettingen, Germany; Department of Microbiology, Kohat University of Science and Technology, 26000 Kohat, Pakistan
| | - Hazir Rahman
- Institute of Clinical Chemistry/UMG-Laboratories, University Medical Centre, Robert Koch Strasse 40, 37075 Goettingen, Germany; Department of Microbiology, Kohat University of Science and Technology, 26000 Kohat, Pakistan
| | - Raees Ahmed
- Institute for Applied Science and Clinical Trials GmbH - IFS, Georg-August University, 37075 Goettingen, Germany
| | - Michael Oellerich
- Institute of Clinical Chemistry/UMG-Laboratories, University Medical Centre, Robert Koch Strasse 40, 37075 Goettingen, Germany
| | - Abdul R Asif
- Institute of Clinical Chemistry/UMG-Laboratories, University Medical Centre, Robert Koch Strasse 40, 37075 Goettingen, Germany.
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14
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Ghosh S, Kaplan KJ, Schrum LW, Bonkovsky HL. Cytoskeletal proteins: shaping progression of hepatitis C virus-induced liver disease. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2013; 302:279-319. [PMID: 23351713 DOI: 10.1016/b978-0-12-407699-0.00005-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Hepatitis C virus (HCV) infection, which results in chronic hepatitis C (CHC) in most patients (70-85%), is a major cause of liver disease and remains a major therapeutic challenge. The mechanisms determining liver damage and the key factors that lead to a high rate of CHC remain imperfectly understood. The precise role of cytoskeletal (CS) proteins in HCV infection remains to be determined. Some studies including our recent study have demonstrated that changes occur in the expression of CS proteins in HCV-infected hepatocytes. A variety of host proteins interact with HCV proteins. Association between CS and HCV proteins may have implications in future design of CS protein-targeted therapy for the treatment for HCV infection. This chapter will focus on the interaction between host CS and viral proteins to signify the importance of this event in HCV entry, replication and transportation.
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Affiliation(s)
- Sriparna Ghosh
- Liver-Biliary-Pancreatic Center, Carolinas Medical Center, and School of Medicine, University of North Carolina, Carolinas Medical Center, Charlotte, NC, USA.
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15
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Glotfelty LG, Hecht GA. Enteropathogenic E. coli effectors EspG1/G2 disrupt tight junctions: new roles and mechanisms. Ann N Y Acad Sci 2012; 1258:149-58. [PMID: 22731728 DOI: 10.1111/j.1749-6632.2012.06563.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Enteropathogenic E. coli (EPEC) infection is a major cause of infantile diarrhea in the developing world. Using a type-three secretion system, bacterial effector proteins are transferred to the host cell cytosol where they affect multiple physiological functions, ultimately leading to diarrheal disease. Disruption of intestinal epithelial cell tight junctions is a major consequence of EPEC infection and is mediated by multiple effector proteins, among them EspG1 and its homologue EspG2. EspG1/G2 contribute to loss of barrier function via an undefined mechanism that may be linked to their disruption of microtubule networks. Recently new investigations have identified additional roles for EspG. Sequestration of active ADP-ribosylating factor (ARF) proteins and promotion of p21-activated kinase (PAK) activity as well as inhibition of Golgi-mediated protein secretion have all been linked to EspG. In this review, we examine the functions of EspG1/G2 and discuss potential mechanisms of EspG-mediated tight junction disruption.
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Affiliation(s)
- Lila G Glotfelty
- Section of Digestive Diseases and Nutrition, Department of Medicine, University of Illinois at Chicago, Chicago, Illinois, USA
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16
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Abstract
Cell polarization is an evolutionarily conserved process that facilitates asymmetric distribution of organelles and proteins and that is modified dynamically during physiological processes such as cell division, migration, and morphogenesis. The plasticity with which cells change their behavior and phenotype in response to cell intrinsic and extrinsic cues is an essential feature of normal physiology. In disease states such as cancer, cells lose their ability to behave normally in response to physiological cues. A molecular understanding of mechanisms that alter the behavior of cancer cells is limited. Cell polarity proteins are a recognized class of molecules that can receive and interpret both intrinsic and extrinsic signals to modulate cell behavior. In this review, we discuss how cell polarity proteins regulate a diverse array of biological processes and how they can contribute to alterations in the behavior of cancer cells.
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Affiliation(s)
- Senthil K Muthuswamy
- Ontario Cancer Institute, Campbell Family Institute for Breast Cancer Research, University of Toronto, Toronto M5G 2M9, Canada.
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17
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O'Driscoll MC, Daly SB, Urquhart JE, Black GC, Pilz DT, Brockmann K, McEntagart M, Abdel-Salam G, Zaki M, Wolf NI, Ladda RL, Sell S, D'Arrigo S, Squier W, Dobyns WB, Livingston JH, Crow YJ. Recessive mutations in the gene encoding the tight junction protein occludin cause band-like calcification with simplified gyration and polymicrogyria. Am J Hum Genet 2010; 87:354-64. [PMID: 20727516 PMCID: PMC2933344 DOI: 10.1016/j.ajhg.2010.07.012] [Citation(s) in RCA: 98] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2010] [Revised: 06/29/2010] [Accepted: 07/08/2010] [Indexed: 11/16/2022] Open
Abstract
Band-like calcification with simplified gyration and polymicrogyria (BLC-PMG) is a rare autosomal-recessive neurological disorder showing highly characteristic clinical and neuroradiological features. Affected individuals demonstrate early-onset seizures, severe microcephaly, and developmental arrest with bilateral, symmetrical polymicrogyria (PMG) and a band of gray matter calcification on brain imaging; as such, the disorder can be considered as a "pseudo-TORCH" syndrome. By using autozygosity mapping and copy number analysis we identified intragenic deletions and mutations in OCLN in nine patients from six families with BLC-PMG. The OCLN gene encodes occludin, an integral component of tight junctions. Neuropathological analysis of an affected individual showed similarity to the mouse model of occludin deficiency with calcification predominantly associated with blood vessels. Both intracranial calcification and PMG are heterogeneous in etiology. Neuropathological and clinical studies of PMG have suggested that in utero ischemic or vascular insults may contribute to this common cortical abnormality. Tight junctions are functional in cerebral blood vessels early in fetal development and continue to play a vital role in maintenance of the blood-brain barrier during postnatal life. We provide evidence that the tight junction protein occludin (encoded by the OCLN gene) is involved in the pathogenesis of malformations of cortical development.
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Affiliation(s)
- Mary C. O'Driscoll
- Genetic Medicine, University of Manchester, Manchester Academic Health Science Centre, Central Manchester Foundation Trust University Hospitals, Manchester, M13 9WL, UK
| | - Sarah B. Daly
- Genetic Medicine, University of Manchester, Manchester Academic Health Science Centre, Central Manchester Foundation Trust University Hospitals, Manchester, M13 9WL, UK
| | - Jill E. Urquhart
- Genetic Medicine, University of Manchester, Manchester Academic Health Science Centre, Central Manchester Foundation Trust University Hospitals, Manchester, M13 9WL, UK
| | - Graeme C.M. Black
- Genetic Medicine, University of Manchester, Manchester Academic Health Science Centre, Central Manchester Foundation Trust University Hospitals, Manchester, M13 9WL, UK
| | - Daniela T. Pilz
- Department of Medical Genetics, University Hospital of Wales, Cardiff, CF14 4XW, UK
| | - Knut Brockmann
- Department of Paediatrics and Paediatric Neurology, Children's Hospital, Georg August University, Robert-Koch-Str. 40, 37075, Goettingen, Germany
| | - Meriel McEntagart
- Department of Clinical Genetics, St. George's Hospital, London, SW17 0RE, UK
| | - Ghada Abdel-Salam
- Clinical Genetics Department, Human Genetics and Genome Research Division, National Research Centre, Cairo, 12311, Egypt
| | - Maha Zaki
- Clinical Genetics Department, Human Genetics and Genome Research Division, National Research Centre, Cairo, 12311, Egypt
| | - Nicole I. Wolf
- Paediatric Neurology, University Children's Hospital, 69120 Heidelberg, Germany
- Department of Child Neurology, VU Medical Center, 1007 MB Amsterdam, The Netherlands
| | - Roger L. Ladda
- Division of Human Genetics, Growth & Development, Department of Pediatrics, Penn State Hershey Children's Hospital, Hershey, PA 17033, USA
| | - Susan Sell
- Division of Human Genetics, Growth & Development, Department of Pediatrics, Penn State Hershey Children's Hospital, Hershey, PA 17033, USA
| | - Stefano D'Arrigo
- Development Neurology Department, Fondazione IRCCS Istituto Neurologico “C. Besta,” 20133 Milan, Italy
| | - Waney Squier
- Departments of Neurology and Neuropathology, Radcliffe Infirmary, Oxford, OX3 9DU, UK
| | - William B. Dobyns
- Departments of Human Genetics, Neurology and Pediatrics, The University of Chicago, Chicago, IL 60637, USA
| | - John H. Livingston
- Department of Paediatric Neurology, Leeds General Infirmary, Leeds, LS9 7TF, UK
| | - Yanick J. Crow
- Genetic Medicine, University of Manchester, Manchester Academic Health Science Centre, Central Manchester Foundation Trust University Hospitals, Manchester, M13 9WL, UK
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18
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Azakir BA, Di Fulvio S, Therrien C, Sinnreich M. Dysferlin interacts with tubulin and microtubules in mouse skeletal muscle. PLoS One 2010; 5:e10122. [PMID: 20405035 PMCID: PMC2853571 DOI: 10.1371/journal.pone.0010122] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2009] [Accepted: 03/11/2010] [Indexed: 12/26/2022] Open
Abstract
Dysferlin is a type II transmembrane protein implicated in surface membrane repair in muscle. Mutations in dysferlin lead to limb girdle muscular dystrophy 2B, Miyoshi Myopathy and distal anterior compartment myopathy. Dysferlin's mode of action is not well understood and only a few protein binding partners have thus far been identified. Using affinity purification followed by liquid chromatography/mass spectrometry, we identified alpha-tubulin as a novel binding partner for dysferlin. The association between dysferlin and alpha-tubulin, as well as between dysferlin and microtubules, was confirmed in vitro by glutathione S-transferase pulldown and microtubule binding assays. These interactions were confirmed in vivo by co-immunoprecipitation. Confocal microscopy revealed that dysferlin and alpha-tubulin co-localized in the perinuclear region and in vesicular structures in myoblasts, and along thin longitudinal structures reminiscent of microtubules in myotubes. We mapped dysferlin's alpha-tubulin-binding region to its C2A and C2B domains. Modulation of calcium levels did not affect dysferlin binding to alpha-tubulin, suggesting that this interaction is calcium-independent. Our studies identified a new binding partner for dysferlin and suggest a role for microtubules in dysferlin trafficking to the sarcolemma.
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Affiliation(s)
- Bilal A. Azakir
- Neuromuscular Research Group, Montreal Neurological Institute and Hospital, McGill University, Montreal, Quebec, Canada
| | - Sabrina Di Fulvio
- Neuromuscular Research Group, Montreal Neurological Institute and Hospital, McGill University, Montreal, Quebec, Canada
| | - Christian Therrien
- Neuromuscular Research Group, Montreal Neurological Institute and Hospital, McGill University, Montreal, Quebec, Canada
| | - Michael Sinnreich
- Neuromuscular Research Group, Montreal Neurological Institute and Hospital, McGill University, Montreal, Quebec, Canada
- Neuromuscular Center, Departments of Neurology and Biomedicine, University Hospital Basel, Basel, Switzerland
- * E-mail:
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19
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McCarter SD, Johnson DL, Kitt KN, Donohue C, Adams A, Wilson JM. Regulation of tight junction assembly and epithelial polarity by a resident protein of apical endosomes. Traffic 2010; 11:856-66. [PMID: 20214753 DOI: 10.1111/j.1600-0854.2010.01052.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The establishment of tight junctions and cell polarity is an essential process in all epithelia. Endotubin is an integral membrane protein found in apical endosomes of developing epithelia when tight junctions and epithelial polarity first arise. We found that the disruption of endotubin function in cells in culture by siRNA or overexpression of the C-terminal cytoplasmic domain of endotubin causes defects in organization and function of tight junctions. We observe defects in localization of tight junction proteins, reduced transepithelial resistance, increased lanthanum penetration between cells and reduced ability of cells to form cysts in three-dimensional culture. In addition, in cells overexpressing the C-terminal domain of endotubin, we observe a delay in re-establishing the normal distribution of endosomes after calcium switch. These results suggest that endotubin regulates trafficking of polarity proteins and tight junction components out of the endosomal compartment, thereby providing a critical link between a resident protein of apical endosomes and tight junctions.
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Affiliation(s)
- Sarah D McCarter
- Department of Cell Biology & Anatomy, University of Arizona, 1501 N. Campbell Avenue, Tucson, AZ 85724, USA
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20
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Lee JW, Hsiao WT, Chen HY, Hsu LP, Chen PR, Lin MD, Chiu SJ, Shih WL, Hsu YC. Upregulated claudin-1 expression confers resistance to cell death of nasopharyngeal carcinoma cells. Int J Cancer 2010; 126:1353-66. [PMID: 19739116 DOI: 10.1002/ijc.24857] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Accumulating evidence reveals that aberrant expression of claudins manifests in various tumors; however, their biological functions are poorly understood. Here, we report on the elevated expression of claudin-1 in nasopharyngeal carcinoma (NPC) cell lines under serum deprivation or fluorouracil (5-FU) treatment. Interestingly, an increase in expression of claudin-1 considerably reduced apoptosis rather than enhancing cell proliferation. However, claudin-1 expression and activity were unaffected by external stimuli or Akt and NF-kappaB activation. Notably, predominant cytoplasmic and nuclear localization of claudin-1 in NPC cells reflected the aforementioned feature. On the other hand, loss of epithelial morphology and E-cadherin expression was associated with serum withdrawal in NPC cells. Interestingly, restoration of E-cadherin inhibited the protein elevation and antiapoptotic activity of claudin-1. In conclusion, our data demonstrate the regulation and novel biological function of claudin-1 and indicate the important role of claudin-1 in NPC tumorigenesis.
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Affiliation(s)
- Jeng-Woei Lee
- Department of Life Sciences, Tzu-Chi University, Hualien 97004, Taiwan.
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21
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The tight junction-associated protein occludin is required for a postbinding step in hepatitis C virus entry and infection. J Virol 2009; 83:8012-20. [PMID: 19515778 DOI: 10.1128/jvi.00038-09] [Citation(s) in RCA: 125] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
The precise mechanisms regulating hepatitis C virus (HCV) entry into hepatic cells remain unknown. However, several cell surface proteins have been identified as entry factors for this virus. Of these molecules, claudin-1, a tight junction (TJ) component, is considered a coreceptor required for HCV entry. Recently, we have demonstrated that HCV envelope glycoproteins (HCVgp) promote structural and functional TJ alterations. Additionally, we have shown that the intracellular interaction between viral E2 glycoprotein and occludin, another TJ-associated protein, could be the cause of the mislocalization of TJ proteins. Herein we demonstrated, by using cell culture-derived HCV particles (HCVcc), that interference of occludin expression markedly reduced HCV infection. Furthermore, our results with HCV pseudotyped particles indicated that occludin, but not other TJ-associated proteins, such as junctional adhesion molecule A or zonula occludens protein 1, was required for HCV entry. Using HCVcc, we demonstrated that occludin did not play an essential role in the initial attachment of HCV to target cells. Surface protein labeling experiments showed that both expression levels and cell surface localization of HCV (co)receptors CD81, scavenger receptor class B type I, and claudin-1 were not affected upon occludin knockdown. In addition, immunofluorescence confocal analysis showed that occludin interference did not affect subcellular distribution of the HCV (co)receptors analyzed. However, HCVgp fusion-associated events were altered after occludin silencing. In summary, we propose that occludin plays an essential role in HCV infection and probably affects late entry events. This observation may provide new insights into HCV infection and related pathogenesis.
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22
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Burlone ME, Budkowska A. Hepatitis C virus cell entry: role of lipoproteins and cellular receptors. J Gen Virol 2009; 90:1055-1070. [PMID: 19264629 DOI: 10.1099/vir.0.008300-0] [Citation(s) in RCA: 151] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Hepatitis C virus (HCV), a major cause of chronic liver disease, is a single-stranded positive sense virus of the family Flaviviridae. HCV cell entry is a multi-step process, involving several viral and cellular factors that trigger virus uptake into the hepatocyte. Tetraspanin CD81, human scavenger receptor SR-BI, and tight junction molecules Claudin-1 and occludin are the main receptors that mediate HCV entry. In addition, the virus may use glycosaminoglycans and/or low density receptors on host cells as initial attachment factors. A unique feature of HCV is the dependence of virus replication and assembly on host cell lipid metabolism. Most notably, during HCV assembly and release from the infected cells, virus particles associate with lipids and very-low-density lipoproteins. Thus, infectious virus circulates in patient sera in the form of triglyceride-rich particles. Consequently, lipoproteins and lipoprotein receptors play an essential role in virus uptake and the initiation of infection. This review summarizes the current knowledge about HCV receptors, mechanisms of HCV cell entry and the role of lipoproteins in this process.
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Affiliation(s)
- Michela E Burlone
- University of Eastern Piedmont 'A. Avogadro', Department of Clinical and Experimental Medicine, Via Solaroli 17, 28100 Novara, Italy.,Pasteur Institute, Hepacivirus and Innate Immunity, 25/28 Rue du Dr Roux, 75724 Paris Cedex 15, France
| | - Agata Budkowska
- Pasteur Institute, Hepacivirus and Innate Immunity, 25/28 Rue du Dr Roux, 75724 Paris Cedex 15, France
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23
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Chen J, Xiao L, Rao JN, Zou T, Liu L, Bellavance E, Gorospe M, Wang JY. JunD represses transcription and translation of the tight junction protein zona occludens-1 modulating intestinal epithelial barrier function. Mol Biol Cell 2008; 19:3701-12. [PMID: 18562690 PMCID: PMC2526696 DOI: 10.1091/mbc.e08-02-0175] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2008] [Revised: 05/30/2008] [Accepted: 06/09/2008] [Indexed: 01/22/2023] Open
Abstract
The AP-1 transcription factor JunD is highly expressed in intestinal epithelial cells, but its exact role in maintaining the integrity of intestinal epithelial barrier remains unknown. The tight junction (TJ) protein zonula occludens (ZO)-1 links the intracellular domain of TJ-transmembrane proteins occludin, claudins, and junctional adhesion molecules to many cytoplasmic proteins and the actin cytoskeleton and is crucial for assembly of the TJ complex. Here, we show that JunD negatively regulates expression of ZO-1 and is implicated in the regulation of intestinal epithelial barrier function. Increased JunD levels by ectopic overexpression of the junD gene or by depleting cellular polyamines repressed ZO-1 expression and increased epithelial paracellular permeability. JunD regulated ZO-1 expression at the levels of transcription and translation. Transcriptional repression of ZO-1 by JunD was mediated through cAMP response element-binding protein-binding site within its proximal region of the ZO-1-promoter, whereas induced JunD inhibited ZO-1 mRNA translation by enhancing the interaction of the ZO-1 3'-untranslated region with RNA-binding protein T cell-restricted intracellular antigen 1-related protein. These results indicate that JunD is a biological suppressor of ZO-1 expression in intestinal epithelial cells and plays a critical role in maintaining epithelial barrier function.
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Affiliation(s)
- Jie Chen
- *Cell Biology Group, Department of Surgery and
- Baltimore Veterans Affairs Medical Center, Baltimore, MD 21201; and
| | - Lan Xiao
- *Cell Biology Group, Department of Surgery and
- Baltimore Veterans Affairs Medical Center, Baltimore, MD 21201; and
| | - Jaladanki N. Rao
- *Cell Biology Group, Department of Surgery and
- Baltimore Veterans Affairs Medical Center, Baltimore, MD 21201; and
| | - Tongtong Zou
- *Cell Biology Group, Department of Surgery and
- Baltimore Veterans Affairs Medical Center, Baltimore, MD 21201; and
| | - Lan Liu
- *Cell Biology Group, Department of Surgery and
- Baltimore Veterans Affairs Medical Center, Baltimore, MD 21201; and
| | - Emily Bellavance
- *Cell Biology Group, Department of Surgery and
- Baltimore Veterans Affairs Medical Center, Baltimore, MD 21201; and
| | - Myriam Gorospe
- Laboratory of Cellular and Molecular Biology, National Institute on Aging-Intramural Research Program, National Institutes of Health, Baltimore, MD 21224
| | - Jian-Ying Wang
- *Cell Biology Group, Department of Surgery and
- Department of Pathology, University of Maryland School of Medicine and
- Baltimore Veterans Affairs Medical Center, Baltimore, MD 21201; and
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