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Hana C, Thaw Dar NN, Galo Venegas M, Vulfovich M. Claudins in Cancer: A Current and Future Therapeutic Target. Int J Mol Sci 2024; 25:4634. [PMID: 38731853 PMCID: PMC11083183 DOI: 10.3390/ijms25094634] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2024] [Revised: 04/16/2024] [Accepted: 04/18/2024] [Indexed: 05/13/2024] Open
Abstract
Claudins are a family of 27 proteins that have an important role in the formation of tight junctions. They also have an important function in ion exchange, cell mobility, and the epithelial-to-mesenchymal transition, the latter being very important in cancer invasion and metastasis. Therapeutic targeting of claudins has been investigated to improve cancer outcomes. Recent evidence shows improved outcomes when combining monoclonal antibodies against claudin 18.2 with chemotherapy for patients with gastroesophageal junction cancer. Currently, chimeric antigen receptor T-cells targeting claudin 18 are under investigation. In this review, we will discuss the major functions of claudins, their distribution in the normal as well as cancerous tissues, and their effect in cancer metastasis, with a special focus on the therapeutic targeting of claudins to improve cancer outcomes.
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Affiliation(s)
- Caroline Hana
- Hematology/Oncology Department, Memorial Healthcare System, Pembroke Pines, FL 33028, USA; (N.N.T.D.); (M.G.V.)
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2
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Segui-Perez C, Stapels DAC, Ma Z, Su J, Passchier E, Westendorp B, Wubbolts RW, Wu W, van Putten JPM, Strijbis K. MUC13 negatively regulates tight junction proteins and intestinal epithelial barrier integrity via protein kinase C. J Cell Sci 2024; 137:jcs261468. [PMID: 38345099 PMCID: PMC10984281 DOI: 10.1242/jcs.261468] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2023] [Accepted: 01/29/2024] [Indexed: 03/14/2024] Open
Abstract
Glycosylated mucin proteins contribute to the essential barrier function of the intestinal epithelium. The transmembrane mucin MUC13 is an abundant intestinal glycoprotein with important functions for mucosal maintenance that are not yet completely understood. We demonstrate that in human intestinal epithelial monolayers, MUC13 localized to both the apical surface and the tight junction (TJ) region on the lateral membrane. MUC13 deletion resulted in increased transepithelial resistance (TEER) and reduced translocation of small solutes. TEER buildup in ΔMUC13 cells could be prevented by addition of MLCK, ROCK or protein kinase C (PKC) inhibitors. The levels of TJ proteins including claudins and occludin were highly increased in membrane fractions of MUC13 knockout cells. Removal of the MUC13 cytoplasmic tail (CT) also altered TJ composition but did not affect TEER. The increased buildup of TJ complexes in ΔMUC13 and MUC13-ΔCT cells was dependent on PKC. The responsible PKC member might be PKCδ (or PRKCD) based on elevated protein levels in the absence of full-length MUC13. Our results demonstrate for the first time that a mucin protein can negatively regulate TJ function and stimulate intestinal barrier permeability.
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Affiliation(s)
- Celia Segui-Perez
- Department of Biomolecular Health Sciences, Division of Infectious Diseases and Immunology, Faculty of Veterinary Medicine, Utrecht University, Yalelaan 1, 3584 CL Utrecht, the Netherlands
| | - Daphne A. C. Stapels
- Department of Biomolecular Health Sciences, Division of Infectious Diseases and Immunology, Faculty of Veterinary Medicine, Utrecht University, Yalelaan 1, 3584 CL Utrecht, the Netherlands
| | - Ziliang Ma
- Biomolecular Mass Spectrometry and Proteomics, Bijvoet Center for Biomolecular Research and Utrecht Institute for Pharmaceutical Sciences, Utrecht University, Padualaan 8, 3584 CH Utrecht, the Netherlands
- Singapore Immunology Network (SIgN), Agency for Science, Technology, and Research (A*STAR), 138648 Singapore, Singapore
- Department of Pharmacy, National University of Singapore, 117543 Singapore, Singapore
| | - Jinyi Su
- Department of Biomolecular Health Sciences, Division of Infectious Diseases and Immunology, Faculty of Veterinary Medicine, Utrecht University, Yalelaan 1, 3584 CL Utrecht, the Netherlands
| | - Elsemieke Passchier
- UMAB, Department of Laboratory Pharmacy and Biomedical Genetics, Center for Translational Immunology, University Medical Center Utrecht, Heidelberglaan 100, 3584 CX Utrecht, the Netherlands
| | - Bart Westendorp
- Department of Biomolecular Health Sciences, Division of Cell Biology, Metabolism and Cancer, Faculty of Veterinary Medicine, Utrecht University, Yalelaan 1, 3584 CL Utrecht, the Netherlands
| | - Richard W. Wubbolts
- Department of Biomolecular Health Sciences, Division of Cell Biology, Metabolism and Cancer, Faculty of Veterinary Medicine, Utrecht University, Yalelaan 1, 3584 CL Utrecht, the Netherlands
| | - Wei Wu
- Biomolecular Mass Spectrometry and Proteomics, Bijvoet Center for Biomolecular Research and Utrecht Institute for Pharmaceutical Sciences, Utrecht University, Padualaan 8, 3584 CH Utrecht, the Netherlands
- Singapore Immunology Network (SIgN), Agency for Science, Technology, and Research (A*STAR), 138648 Singapore, Singapore
- Department of Pharmacy, National University of Singapore, 117543 Singapore, Singapore
| | - Jos P. M. van Putten
- Department of Biomolecular Health Sciences, Division of Infectious Diseases and Immunology, Faculty of Veterinary Medicine, Utrecht University, Yalelaan 1, 3584 CL Utrecht, the Netherlands
| | - Karin Strijbis
- Department of Biomolecular Health Sciences, Division of Infectious Diseases and Immunology, Faculty of Veterinary Medicine, Utrecht University, Yalelaan 1, 3584 CL Utrecht, the Netherlands
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3
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Raya-Sandino A, Lozada-Soto KM, Rajagopal N, Garcia-Hernandez V, Luissint AC, Brazil JC, Cui G, Koval M, Parkos CA, Nangia S, Nusrat A. Claudin-23 reshapes epithelial tight junction architecture to regulate barrier function. Nat Commun 2023; 14:6214. [PMID: 37798277 PMCID: PMC10556055 DOI: 10.1038/s41467-023-41999-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2022] [Accepted: 09/26/2023] [Indexed: 10/07/2023] Open
Abstract
Claudin family tight junction proteins form charge- and size-selective paracellular channels that regulate epithelial barrier function. In the gastrointestinal tract, barrier heterogeneity is attributed to differential claudin expression. Here, we show that claudin-23 (CLDN23) is enriched in luminal intestinal epithelial cells where it strengthens the epithelial barrier. Complementary approaches reveal that CLDN23 regulates paracellular ion and macromolecule permeability by associating with CLDN3 and CLDN4 and regulating their distribution in tight junctions. Computational modeling suggests that CLDN23 forms heteromeric and heterotypic complexes with CLDN3 and CLDN4 that have unique pore architecture and overall net charge. These computational simulation analyses further suggest that pore properties are interaction-dependent, since differently organized complexes with the same claudin stoichiometry form pores with unique architecture. Our findings provide insight into tight junction organization and propose a model whereby different claudins combine to form multiple distinct complexes that modify epithelial barrier function by altering tight junction structure.
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Affiliation(s)
- Arturo Raya-Sandino
- Department of Pathology, University of Michigan Medical School, Ann Arbor, MI, USA
| | | | - Nandhini Rajagopal
- Department of Biomedical and Chemical Engineering, Syracuse University, Syracuse, NY, USA
| | | | - Anny-Claude Luissint
- Department of Pathology, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Jennifer C Brazil
- Department of Pathology, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Guiying Cui
- Department of Pediatrics, Emory + Children's Center for Cystic Fibrosis and Airways Disease Research, Emory University School of Medicine, Atlanta, GA, USA
| | - Michael Koval
- Departments of Medicine and Cell Biology, Emory University School of Medicine, Atlanta, GA, USA
| | - Charles A Parkos
- Department of Pathology, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Shikha Nangia
- Department of Biomedical and Chemical Engineering, Syracuse University, Syracuse, NY, USA.
| | - Asma Nusrat
- Department of Pathology, University of Michigan Medical School, Ann Arbor, MI, USA.
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4
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Zheng X, Ren B, Gao Y. Tight junction proteins related to blood-brain barrier and their regulatory signaling pathways in ischemic stroke. Biomed Pharmacother 2023; 165:115272. [PMID: 37544283 DOI: 10.1016/j.biopha.2023.115272] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2023] [Revised: 07/29/2023] [Accepted: 07/31/2023] [Indexed: 08/08/2023] Open
Abstract
Tight junctions (TJs) are crucial for intercellular connections. The abnormal expression of proteins related to TJs can result in TJ destruction, structural damage, and endothelial and epithelial cell dysfunction. These factors are associated with the occurrence and progression of several diseases. Studies have shown that blood-brain barrier (BBB) damage and dysfunction are the prominent pathological features of stroke. TJs are directly associated with the BBB integrity. In this article, we first discuss the structure and function of BBB TJ-related proteins before focusing on the crucial events that cause TJ dysfunction and BBB damage, as well as the regulatory mechanisms that affect the qualitative and quantitative expression of TJ proteins during ischemic stroke. Multiple regulatory mechanisms, including phosphorylation, matrix metalloproteinases (MMPs), and microRNAs, regulate TJ-related proteins and affect BBB permeability. Some signaling pathways and mechanisms have been demonstrated to have dual functions. Hopefully, our understanding of the regulation of BBB TJs in ischemic stroke will be applied to the development of targeted medications and therapeutic therapies.
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Affiliation(s)
- Xiangyi Zheng
- Dongzhimen Hospital, Beijing University of Chinese Medicine, Beijing, China
| | - Beida Ren
- Dongzhimen Hospital, Beijing University of Chinese Medicine, Beijing, China; Institute for Brain Disorders, Beijing University of Chinese Medicine, Beijing, China.
| | - Ying Gao
- Dongzhimen Hospital, Beijing University of Chinese Medicine, Beijing, China; Institute for Brain Disorders, Beijing University of Chinese Medicine, Beijing, China.
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5
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Sanches Santos Rizzo Zuttion M, Moore SKL, Chen P, Beppu AK, Hook JL. New Insights into the Alveolar Epithelium as a Driver of Acute Respiratory Distress Syndrome. Biomolecules 2022; 12:biom12091273. [PMID: 36139112 PMCID: PMC9496395 DOI: 10.3390/biom12091273] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2022] [Revised: 09/02/2022] [Accepted: 09/08/2022] [Indexed: 11/29/2022] Open
Abstract
The alveolar epithelium serves as a barrier between the body and the external environment. To maintain efficient gas exchange, the alveolar epithelium has evolved to withstand and rapidly respond to an assortment of inhaled, injury-inducing stimuli. However, alveolar damage can lead to loss of alveolar fluid barrier function and exuberant, non-resolving inflammation that manifests clinically as acute respiratory distress syndrome (ARDS). This review discusses recent discoveries related to mechanisms of alveolar homeostasis, injury, repair, and regeneration, with a contemporary emphasis on virus-induced lung injury. In addition, we address new insights into how the alveolar epithelium coordinates injury-induced lung inflammation and review maladaptive lung responses to alveolar damage that drive ARDS and pathologic lung remodeling.
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Affiliation(s)
- Marilia Sanches Santos Rizzo Zuttion
- Women’s Guild Lung Institute, Division of Pulmonary and Critical Care Medicine, Department of Medicine, Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA
| | - Sarah Kathryn Littlehale Moore
- Lung Imaging Laboratory, Division of Pulmonary, Critical Care, and Sleep Medicine, Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Peter Chen
- Women’s Guild Lung Institute, Division of Pulmonary and Critical Care Medicine, Department of Medicine, Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA
- Department of Biomedical Sciences, Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA
| | - Andrew Kota Beppu
- Women’s Guild Lung Institute, Division of Pulmonary and Critical Care Medicine, Department of Medicine, Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA
- Regenerative Medicine Institute, Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA
| | - Jaime Lynn Hook
- Lung Imaging Laboratory, Division of Pulmonary, Critical Care, and Sleep Medicine, Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
- Global Health and Emerging Pathogens Institute, Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
- Correspondence:
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6
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Hu Y, van Baal J, Hendriks WH, Resink JW, Liesegang A, van Krimpen MM, Bikker P. High dietary Ca and microbial phytase reduce expression of Ca transporters while enhancing claudins involved in paracellular Ca absorption in the porcine jejunum and colon. Br J Nutr 2022; 129:1-23. [PMID: 35912696 PMCID: PMC10011584 DOI: 10.1017/s0007114522002239] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2022] [Revised: 06/28/2022] [Accepted: 07/07/2022] [Indexed: 11/06/2022]
Abstract
Expression levels of genes (RT-qPCR) related to Ca and P homeostasis (transporters and claudins (CLDN)) were determined in porcine jejunal and colonic mucosa. Forty growing pigs (BW 30.4±1.3 kg) received a low and high Ca content (2.0 and 9.6 g/kg, respectively) diet with or without microbial phytase (500 FTU/kg) for 21 days. Dietary Ca intake enhanced serum Ca and alkaline phosphatase concentration and reduced P, 1,25(OH)2D3, and parathyroid hormone concentration. Jejunal TRPV5 mRNA expression was decreased (32%) with phytase inclusion only, while colonic transient receptor potential vanilloid 5 (TRPV5) mRNA was reduced by dietary Ca (34%) and phytase (44%). Both jejunal and colonic TRPV6 mRNA expression was reduced (30%) with microbial phytase. Calbindin-D9k mRNA expression was lower in colonic but not jejunal mucosa with high dietary Ca (59%) and microbial phytase (37%). None of the mRNAs encoding the Na-P cotransporters (NaPi-IIc, PiT-1, PiT-2) were affected. Jejunal, but not colonic expression of the phosphate transporter XPR1, was slightly downregulated with dietary Ca. Dietary Ca downregulated colonic CLDN-4 (20%) and -10 (40%) expression while CLDN-7 was reduced by phytase inclusion in pigs fed low dietary Ca. Expression of colonic CLDN-12 tended to be increased by phytase. In jejunal mucosa, dietary Ca increased CLDN-2 expression (48%) and decreased CLDN-10 (49%) expression, while phytase slightly upregulated CLDN-12 expression. In conclusion, compared to a Ca deficient phytase-free diet, high dietary Ca and phytase intake in pigs downregulate jejunal and colonic genes related to transcellular Ca absorption and upregulate Ca pore-forming claudins.
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Affiliation(s)
- Yixin Hu
- Wageningen University and Research, Wageningen Livestock Research, Wageningen, 6700, the Netherlands
- Wageningen University and Research, Animal Nutrition Group, Wageningen, the Netherlands
| | - Jurgen van Baal
- Wageningen University and Research, Animal Nutrition Group, Wageningen, the Netherlands
| | - Wouter H. Hendriks
- Wageningen University and Research, Animal Nutrition Group, Wageningen, the Netherlands
| | | | - Annette Liesegang
- University of Zurich, Institute of Animal Nutrition, Vetsuisse Faculty, Zürich, Switzerland
| | - Marinus M. van Krimpen
- Wageningen University and Research, Wageningen Livestock Research, Wageningen, 6700, the Netherlands
| | - Paul Bikker
- Wageningen University and Research, Wageningen Livestock Research, Wageningen, 6700, the Netherlands
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7
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Shashikanth N, France MM, Xiao R, Haest X, Rizzo HE, Yeste J, Reiner J, Turner JR. Tight junction channel regulation by interclaudin interference. Nat Commun 2022; 13:3780. [PMID: 35773259 PMCID: PMC9246906 DOI: 10.1038/s41467-022-31587-8] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2021] [Accepted: 06/23/2022] [Indexed: 02/06/2023] Open
Abstract
Tight junctions form selectively permeable seals across the paracellular space. Both barrier function and selective permeability have been attributed to members of the claudin protein family, which can be categorized as pore-forming or barrier-forming. Here, we show that claudin-4, a prototypic barrier-forming claudin, reduces paracellular permeability by a previously unrecognized mechanism. Claudin-4 knockout or overexpression has minimal effects on tight junction permeability in the absence of pore-forming claudins. However, claudin-4 selectively inhibits flux across cation channels formed by claudins 2 or 15. Claudin-4-induced loss of claudin channel function is accompanied by reduced anchoring and subsequent endocytosis of pore-forming claudins. Analyses in nonepithelial cells show that claudin-4, which is incapable of independent polymerization, disrupts polymeric strands and higher order meshworks formed by claudins 2, 7, 15, and 19. This process of interclaudin interference, in which one claudin disrupts higher order structures and channels formed by a different claudin, represents a previously unrecognized mechanism of barrier regulation.
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Affiliation(s)
- Nitesh Shashikanth
- Laboratory of Mucosal Barrier Pathobiology, Department of Pathology, Brigham and Women's Hospital and Harvard Medical School, Boston, MA, USA
| | - Marion M France
- Laboratory of Mucosal Barrier Pathobiology, Department of Pathology, Brigham and Women's Hospital and Harvard Medical School, Boston, MA, USA
| | - Ruyue Xiao
- Laboratory of Mucosal Barrier Pathobiology, Department of Pathology, Brigham and Women's Hospital and Harvard Medical School, Boston, MA, USA
| | - Xenia Haest
- Laboratory of Mucosal Barrier Pathobiology, Department of Pathology, Brigham and Women's Hospital and Harvard Medical School, Boston, MA, USA
| | - Heather E Rizzo
- Laboratory of Mucosal Barrier Pathobiology, Department of Pathology, Brigham and Women's Hospital and Harvard Medical School, Boston, MA, USA
| | - Jose Yeste
- Laboratory of Mucosal Barrier Pathobiology, Department of Pathology, Brigham and Women's Hospital and Harvard Medical School, Boston, MA, USA
- Instituto de Microelectrónica de Barcelona, IMB-CNM (CSIC), Bellaterra, Spain
| | - Johannes Reiner
- Division of Gastroenterology and Endocrinology, Department of Medicine II, Rostock University Medical Center, Ernst-Heydemann-Str. 6, Rostock, Germany
| | - Jerrold R Turner
- Laboratory of Mucosal Barrier Pathobiology, Department of Pathology, Brigham and Women's Hospital and Harvard Medical School, Boston, MA, USA.
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8
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Ahlswede L, Siebenaller C, Junglas B, Hellmann N, Schneider D. Human Claudin-7 cis-Interactions Are Not Crucial for Membrane-Membrane (Trans-) Interactions. Front Mol Biosci 2022; 9:908383. [PMID: 35832741 PMCID: PMC9271825 DOI: 10.3389/fmolb.2022.908383] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2022] [Accepted: 06/07/2022] [Indexed: 11/13/2022] Open
Abstract
Human Claudin-7 (Cldn7) is a member of the Claudin (Cldn) superfamily. In vivo, these proteins form tight junctions, which establish constricted connections between cells. Cldns oligomerize within the membrane plane (= cis-interaction), and also interact with Cldns from adjacent cells (= trans-interaction). Interactions of Cldns are typically studied in vivo and structural analyses of isolated Cldns are limited. Here, we describe heterologous expression in E. coli and purification of human Cldn7, enabling in vitro analyses of the isolated protein using detergent and model membrane systems. Cldn7 exists as a monomer, hexamer, and various higher oligomers in micelles. While only limited unfolding of the protein was observed in the presence of the anionic detergent sodium dodecyl sulfate, decreased ionic strength did affect Cldn7 cis-interactions. Furthermore, we identified two amino acids which mediate electrostatic cis-interactions and analyzed the impact of disturbed cis-interaction on trans-contacts via atomic force microscopy and monitoring Förster resonance energy transfer between fluorescently labeled Cldn7-containing proteoliposomes. Our results indicate that Cldn7 cis-oligomerization might not be a prerequisite for establishing trans-contacts.
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Affiliation(s)
- Lena Ahlswede
- Department of Chemistry, Biochemistry, Johannes Gutenberg University Mainz, Mainz, Germany
| | - Carmen Siebenaller
- Department of Chemistry, Biochemistry, Johannes Gutenberg University Mainz, Mainz, Germany
| | - Benedikt Junglas
- Department of Chemistry, Biochemistry, Johannes Gutenberg University Mainz, Mainz, Germany
| | - Nadja Hellmann
- Department of Chemistry, Biochemistry, Johannes Gutenberg University Mainz, Mainz, Germany
| | - Dirk Schneider
- Department of Chemistry, Biochemistry, Johannes Gutenberg University Mainz, Mainz, Germany
- Institute of Molecular Physiology, Johannes Gutenberg University Mainz, Mainz, Germany
- *Correspondence: Dirk Schneider,
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Jo CH, Kim S, Kim GH. Claudins in kidney health and disease. Kidney Res Clin Pract 2022; 41:275-287. [PMID: 35354245 PMCID: PMC9184838 DOI: 10.23876/j.krcp.21.279] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2021] [Accepted: 12/29/2021] [Indexed: 11/04/2022] Open
Abstract
Claudins are strategically located to exert their physiologic actions along with the nephron segments from the glomerulus. Claudin-1 is normally located in the Bowman’s capsule, but its overexpression can reach the podocytes and lead to albuminuria. In the proximal tubule (PT), claudin-2 forms paracellular channels selective for water, Na+, K+, and Ca2+. Claudin-2 gene mutations are associated with hypercalciuria and kidney stones. Claudin-10 has two splice variants, -10a and -10b; Claudin-10a acts as an anion-selective channel in the PT, and claudin-10b functions as a cation-selective pore in the thick ascending limb (TAL). Claudin-16 and claudin-19 mediate paracellular transport of Na+, Ca2+, and Mg2+ in the TAL, where the expression of claudin-3/16/19 and claudin-10b are mutually exclusive. The claudin-16 or -19 mutation causes familial hypomagnesemia with hypercalciuria and nephrocalcinosis. Claudin-14 polymorphisms have been linked to increased risk of hypercalciuria. Claudin-10b mutations produce HELIX syndrome, which encompasses hypohidrosis, electrolyte imbalance, lacrimal gland dysfunction, ichthyosis, and xerostomia. Hypercalciuria and magnesuria in metabolic acidosis are related to downregulation of PT and TAL claudins. In the TAL, stimulation of calcium-sensing receptors upregulates claudin-14 and negatively acts on the claudin-16/19 complex. Claudin-3 acts as a general barrier to ions in the collecting duct. If this barrier is disturbed, urine acidification might be impaired. Claudin-7 forms a nonselective paracellular channel facilitating Cl– and Na+ reabsorption in the collecting ducts. Claudin-4 and -8 serve as anion channels and mediate paracellular Cl– transport; their upregulation may contribute to pseudohypoaldosteronism II and salt-sensitive hypertension.
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Affiliation(s)
- Chor ho Jo
- Hanyang Biomedical Research Institute, Hanyang University College of Medicine, Seoul, Republic of Korea
| | - Sua Kim
- Hanyang Biomedical Research Institute, Hanyang University College of Medicine, Seoul, Republic of Korea
| | - Gheun-Ho Kim
- Hanyang Biomedical Research Institute, Hanyang University College of Medicine, Seoul, Republic of Korea
- Department of Internal Medicine, Hanyang University College of Medicine, Seoul, Republic of Korea
- Correspondence: Gheun-Ho Kim Department of Internal Medicine, Hanyang University College of Medicine, 222-1 Wangsimni-ro, Seongdong-gu, Seoul 04763, Republic of Korea. E-mail:
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10
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Loxoprofen enhances intestinal barrier function via generation of its active metabolite by carbonyl reductase 1 in differentiated Caco-2 cells. Chem Biol Interact 2021; 348:109634. [PMID: 34506768 DOI: 10.1016/j.cbi.2021.109634] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2021] [Revised: 08/31/2021] [Accepted: 09/05/2021] [Indexed: 02/06/2023]
Abstract
Nonsteroidal anti-inflammatory drugs (NSAIDs) are used worldwide as antipyretic analgesics and agents for rheumatoid arthritis and osteoarthritis, but known to cause damage to the gastrointestinal mucosae as their serious adverse effects. Few studies showed the impairment of intestinal epithelial barrier function (EBF) by high concentrations (0.5-1 mM) of NSAIDs, but the underlying mechanism is not fully understood. This study is aimed at clarifying effects at a low concentration (50 μM) of three NSAIDs, loxoprofen (Lox), ibuprofen and indomethacin, on intestinal EBF using human intestinal epithelial-like Caco-2 cells. Among those NSAIDs, Lox increased the transepithelial electric resistance (TER) value, decreased the paracellular Lucifer yellow CH (LYCH) permeability, and upregulated claudin (CLDN)-1, -3 and -5, indicating that low doses of Lox enhanced EBF through increasing expression of CLDNs. Lox is known to be metabolized to a pharmacologically active metabolite, (2S,1'R,2'S)-loxoprofen alcohol (Lox-RS), by carbonyl reductase 1 (CBR1), which is highly expressed in human intestine. CBR1 was expressed in the Caco-2 cells, and the pretreatment with a CBR1 inhibitor suppressed both the Lox-evoked CLDN upregulation and EBF enhancement. In addition, the treatment of the cells with Lox-RS resulted in higher TER value and lower LYCH permeability than those with Lox. Thus, Lox-RS synthesized by CBR1 may greatly contribute to the improving efficacy of Lox on the barrier function. Since EBF is decreased in inflammatory bowel disease, we finally examined the effect of Lox on EBF using the Caco-2/THP-1 co-culture system, which is used as an in vitro inflammatory bowel disease model. Lox significantly recovered EBF which was impaired by inflammatory cytokines secreted from THP-1 macrophages. These in vitro observations suggest that Lox enhances intestinal EBF, for which the metabolism of Lox to Lox-RS by CBR1 has an important role.
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11
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Petito V, Greco V, Laterza L, Graziani C, Fanali C, Lucchetti D, Barbaro MR, Bugli F, Pieroni L, Lopetuso LR, Sgambato A, Sanguinetti M, Scaldaferri F, Urbani A, Gasbarrini A. Impact of the Trophic Effects of the Secretome From a Multistrain Probiotic Preparation on the Intestinal Epithelia. Inflamm Bowel Dis 2021; 27:902-913. [PMID: 33300553 DOI: 10.1093/ibd/izaa298] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/03/2019] [Indexed: 12/13/2022]
Abstract
BACKGROUND Probiotics are defined as live, nonpathogenic bacteria that confer health benefits beyond their nutritional value. In particular, VSL#3 exhibits demonstrated efficacy in the management of diseases characterized by an increased intestinal permeability. Our study aimed to understand how VSL#3 promotes gut health by secreting bioactive factors and identify which human pathways are modulated by secretome derived from the VSL#3 formula. METHODS Two different lots of VSL#3 were used, and Caco-2 cell line was treated with conditioned media (CM) prepared using 1 g of the probiotic formula. We evaluated the effects of the probiotics on cellular proliferation and apoptosis by cytometry and the expression of tight junction proteins by western blotting. A proteomics analysis of both culture media and the whole proteome of Caco-2 cells treated with VSL#3-CM was performed by nano-ultra performance liquid chromatography - tandem mass (nUPLC MS/MS) spectrometry. RESULTS The probiotic formula increased cell proliferation, decreased cellular apoptosis cells, and increased re-epithelialization in the scratch assay. Several peptides specifically synthetized by all the species within the probiotic preparation were recognized in the proteomics analysis. Human proteins synthesized by CaCo-2 cells were also identified. CONCLUSIONS To our knowledge, this manuscript describes the first evaluation of the probiotic secretome, and the results showed that the improvement in intestinal barrier functions induced by probiotics seems to be accompanied by the modulation of some human cellular pathways.
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Affiliation(s)
- Valentina Petito
- Università Cattolica del Sacro Cuore, Dipartimento Universitario di Medicina e Chirurgia Traslazionale, Rome, Italy
| | - Viviana Greco
- Università Cattolica del Sacro Cuore, Dipartimento Universitario di Medicina e Chirurgia Traslazionale, Rome, Italy.,Università Cattolica del Sacro Cuore, Dipartimento Universitario di Scienze Biotecnologiche di Base, Cliniche Intensivologiche e Perioperatorie, Rome, Italy
| | - Lucrezia Laterza
- Fondazione Policlinico Universitario "A. Gemelli" IRCCS, Dipartimento di Scienze di Laboratorio e Infettivologiche, Rome, Italy
| | - Cristina Graziani
- Fondazione Policlinico Universitario "A. Gemelli" IRCCS, Dipartimento di Scienze di Laboratorio e Infettivologiche, Rome, Italy
| | - Caterina Fanali
- Fondazione Policlinico Universitario "A. Gemelli" IRCCS, Dipartimento di Scienze di Laboratorio e Infettivologiche, Rome, Italy
| | - Donatella Lucchetti
- Università Cattolica del Sacro Cuore, Dipartimento Universitario di Medicina e Chirurgia Traslazionale, Rome, Italy
| | - Maria Raffaella Barbaro
- Fondazione Policlinico Universitario "A. Gemelli" IRCCS, Dipartimento di Scienze Mediche e Chirurgiche, Rome, Italy
| | - Francesca Bugli
- Policlinico Sant'Orsola- Malpighi, Università di Bologna, Dipartimento di Scienze Mediche e Chirurgiche, Bologna, Italia
| | - Luisa Pieroni
- Fondazione Santa Lucia IRCCS, Unitá di Proteomica e Metabolomica, Rome, Italy
| | - Loris Riccardo Lopetuso
- Università Cattolica del Sacro Cuore, Dipartimento Universitario di Medicina e Chirurgia Traslazionale, Rome, Italy.,Fondazione Policlinico Universitario "A. Gemelli" IRCCS, Dipartimento di Scienze di Laboratorio e Infettivologiche, Rome, Italy
| | - Alessandro Sgambato
- Università Cattolica del Sacro Cuore, Dipartimento Universitario di Medicina e Chirurgia Traslazionale, Rome, Italy
| | - Maurizio Sanguinetti
- Università Cattolica del Sacro Cuore, Dipartimento Universitario di Medicina e Chirurgia Traslazionale, Rome, Italy.,Università Cattolica del Sacro Cuore, Dipartimento Universitario di Scienze Biotecnologiche di Base, Cliniche Intensivologiche e Perioperatorie, Rome, Italy
| | - Franco Scaldaferri
- Università Cattolica del Sacro Cuore, Dipartimento Universitario di Medicina e Chirurgia Traslazionale, Rome, Italy.,Fondazione Policlinico Universitario "A. Gemelli" IRCCS, Dipartimento di Scienze di Laboratorio e Infettivologiche, Rome, Italy
| | - Andrea Urbani
- Università Cattolica del Sacro Cuore, Dipartimento Universitario di Medicina e Chirurgia Traslazionale, Rome, Italy.,Università Cattolica del Sacro Cuore, Dipartimento Universitario di Scienze Biotecnologiche di Base, Cliniche Intensivologiche e Perioperatorie, Rome, Italy
| | - Antonio Gasbarrini
- Università Cattolica del Sacro Cuore, Dipartimento Universitario di Medicina e Chirurgia Traslazionale, Rome, Italy.,Fondazione Policlinico Universitario "A. Gemelli" IRCCS, Dipartimento di Scienze di Laboratorio e Infettivologiche, Rome, Italy
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12
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Liu M, Xie W, Wan X, Deng T. Clostridium butyricum protects intestinal barrier function via upregulation of tight junction proteins and activation of the Akt/mTOR signaling pathway in a mouse model of dextran sodium sulfate-induced colitis. Exp Ther Med 2020; 20:10. [PMID: 32934675 PMCID: PMC7471846 DOI: 10.3892/etm.2020.9138] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2020] [Accepted: 07/01/2020] [Indexed: 12/14/2022] Open
Abstract
Clostridium butyricum (CB), a probiotic, is a gram-positive obligate anaerobic bacillus with acid and heat resistant properties. Previous studies have reported that CB has beneficial effects in intestinal diseases and regulates intestinal function. The aim of the present study was to investigate the protective effects and mechanisms of CB on the intestinal barrier function. Mice were randomly divided into three experimental groups (n=15 mice/group), including control, dextran sodium sulfate (DSS) and DSS + CB. In the DSS and DSS + CB groups colitis was induced with 3% DSS dissolved in drinking water for 7 days. DSS + CB group mice were co-treated daily with 200 µl (2x108 CFU) CB solution via gavage. The intestinal mucosal barrier function in mice was assessed by measuring FITC-labeled 4-kDa dextran (molecular weight, 4,000 Da) flux and by analyzing the expression of tight junction (TJ)-related proteins using western blot analysis. In addition, the secretion levels of tumor necrosis factor-α (TNF-α), interleukin (IL)-1β, IL-6, IL-10 and IL-13, and the concentration of malondialdehyde, glutathione and superoxide dismutase were detected using ELISAs to determine inflammation and oxidative stress, respectively. The activation status of the Akt/mTOR signaling pathway was also investigated using western blot analysis. The results demonstrated that, in mice with DSS-induced colitis treatment, co-treatment with CB attenuated colitis symptoms and intestinal permeability, increased the expression levels of TJ-related proteins, decreased TNF-α, IL-1β and IL-13 secretion levels but increased those of IL-10, and reduced oxidative stress. Additionally, CB elevated the phosphorylation of Akt, mTOR and p70 ribosomal protein S6 kinase. Collectively, the present results indicated that CB protected intestinal barrier function and decreased intestinal mucosal permeability via upregulating the expression levels of TJ-related proteins in a mouse model of DSS-induced colitis. Moreover, the results suggested that the effects of CB could be mediated by the Akt/mTOR signaling pathway.
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Affiliation(s)
- Miao Liu
- Department of Gastroenterology, Renmin Hospital of Wuhan University, Wuhan, Hubei 430060, P.R. China.,Key Laboratory of Hubei Province for Digestive System Disease, Wuhan, Hubei 430060, P.R. China.,Central Laboratory of Renmin Hospital, Wuhan, Hubei 430060, P.R. China
| | - Wenjie Xie
- Central Laboratory of Renmin Hospital, Wuhan, Hubei 430060, P.R. China.,Department of Critical Care Medicine, Renmin Hospital of Wuhan University, Wuhan, Hubei 430060, P.R. China
| | - Xinyue Wan
- Department of Gastroenterology, Renmin Hospital of Wuhan University, Wuhan, Hubei 430060, P.R. China.,Key Laboratory of Hubei Province for Digestive System Disease, Wuhan, Hubei 430060, P.R. China.,Central Laboratory of Renmin Hospital, Wuhan, Hubei 430060, P.R. China
| | - Tao Deng
- Department of Gastroenterology, Renmin Hospital of Wuhan University, Wuhan, Hubei 430060, P.R. China.,Key Laboratory of Hubei Province for Digestive System Disease, Wuhan, Hubei 430060, P.R. China.,Central Laboratory of Renmin Hospital, Wuhan, Hubei 430060, P.R. China
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13
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Claudins in the Renal Collecting Duct. Int J Mol Sci 2019; 21:ijms21010221. [PMID: 31905642 PMCID: PMC6981911 DOI: 10.3390/ijms21010221] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2019] [Revised: 12/20/2019] [Accepted: 12/20/2019] [Indexed: 12/12/2022] Open
Abstract
The renal collecting duct fine-tunes urinary composition, and thereby, coordinates key physiological processes, such as volume/blood pressure regulation, electrolyte-free water reabsorption, and acid-base homeostasis. The collecting duct epithelium is comprised of a tight epithelial barrier resulting in a strict separation of intraluminal urine and the interstitium. Tight junctions are key players in enforcing this barrier and in regulating paracellular transport of solutes across the epithelium. The features of tight junctions across different epithelia are strongly determined by their molecular composition. Claudins are particularly important structural components of tight junctions because they confer barrier and transport properties. In the collecting duct, a specific set of claudins (Cldn-3, Cldn-4, Cldn-7, Cldn-8) is expressed, and each of these claudins has been implicated in mediating aspects of the specific properties of its tight junction. The functional disruption of individual claudins or of the overall barrier function results in defects of blood pressure and water homeostasis. In this concise review, we provide an overview of the current knowledge on the role of the collecting duct epithelial barrier and of claudins in collecting duct function and pathophysiology.
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14
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Fan J, Tatum R, Hoggard J, Chen YH. Claudin-7 Modulates Cl - and Na + Homeostasis and WNK4 Expression in Renal Collecting Duct Cells. Int J Mol Sci 2019; 20:ijms20153798. [PMID: 31382627 PMCID: PMC6696617 DOI: 10.3390/ijms20153798] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2019] [Accepted: 07/30/2019] [Indexed: 12/17/2022] Open
Abstract
Claudin-7 knockout (CLDN7-/-) mice display renal salt wasting and dehydration phenotypes. To address the role of CLDN7 in kidneys, we established collecting duct (CD) cell lines from CLDN7+/+ and CLDN7-/- mouse kidneys. We found that deletion of CLDN7 increased the transepithelial resistance (TER) and decreased the paracellular permeability for Cl- and Na+ in CLDN7-/- CD cells. Inhibition of transcellular Cl- and Na+ channels has no significant effect on TER or dilution potentials. Current-voltage curves were linear in both CLDN7+/+ and CLDN7-/- CD cells, indicating that the ion flux was through the paracellular pathway. The impairment of Cl- and Na+ permeability phenotype can be rescued by CLDN7 re-expression. We also found that WNK4 (its mutations lead to hypertension) expression, but not WNK1, was significantly increased in CLDN7-/- CD cell lines as well as in primary CLDN7-/- CD cells, suggesting that the expression of WNK4 was modulated by CLDN7. In addition, deletion of CLDN7 upregulated the expression level of the apical epithelial sodium channel (ENaC), indicating a potential cross-talk between paracellular and transcellular transport systems. This study demonstrates that CLDN7 plays an important role in salt balance in renal CD cells and modulating WNK4 and ENaC expression levels that are vital in controlling salt-sensitive hypertension.
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Affiliation(s)
- Junming Fan
- Department of Anatomy and Cell Biology, Brody School of Medicine, East Carolina University, Greenville, NC 27834, USA
- Institute of Hypoxia Medicine, School of Basic Medical Sciences, Wenzhou Medical University, Wenzhou 325035, China
| | - Rodney Tatum
- Department of Anatomy and Cell Biology, Brody School of Medicine, East Carolina University, Greenville, NC 27834, USA
| | - John Hoggard
- Department of Anatomy and Cell Biology, Brody School of Medicine, East Carolina University, Greenville, NC 27834, USA
| | - Yan-Hua Chen
- Department of Anatomy and Cell Biology, Brody School of Medicine, East Carolina University, Greenville, NC 27834, USA.
- East Carolina Diabetes and Obesity Institute, East Carolina University, Greenville, NC 27834, USA.
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15
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Tsukita S, Tanaka H, Tamura A. The Claudins: From Tight Junctions to Biological Systems. Trends Biochem Sci 2019; 44:141-152. [DOI: 10.1016/j.tibs.2018.09.008] [Citation(s) in RCA: 127] [Impact Index Per Article: 25.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2018] [Revised: 09/17/2018] [Accepted: 09/19/2018] [Indexed: 01/04/2023]
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16
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Workinger JL, Doyle RP, Bortz J. Challenges in the Diagnosis of Magnesium Status. Nutrients 2018; 10:E1202. [PMID: 30200431 PMCID: PMC6163803 DOI: 10.3390/nu10091202] [Citation(s) in RCA: 84] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2018] [Revised: 08/24/2018] [Accepted: 08/27/2018] [Indexed: 12/31/2022] Open
Abstract
Magnesium is a critical mineral in the human body and is involved in ~80% of known metabolic functions. It is currently estimated that 60% of adults do not achieve the average dietary intake (ADI) and 45% of Americans are magnesium deficient, a condition associated with disease states like hypertension, diabetes, and neurological disorders, to name a few. Magnesium deficiency can be attributed to common dietary practices, medications, and farming techniques, along with estimates that the mineral content of vegetables has declined by as much as 80⁻90% in the last 100 years. However, despite this mineral's importance, it is poorly understood from several standpoints, not the least of which is its unique mechanism of absorption and sensitive compartmental handling in the body, making the determination of magnesium status difficult. The reliance on several popular sample assays has contributed to a great deal of confusion in the literature. This review will discuss causes of magnesium deficiency, absorption, handling, and compartmentalization in the body, highlighting the challenges this creates in determining magnesium status in both clinical and research settings.
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Affiliation(s)
- Jayme L Workinger
- Human Nutrition and Pharma, Balchem Corporation, 52 Sunrise Park Road, New Hampton, NY 10958, USA.
| | - Robert P Doyle
- Department of Chemistry, Center for Science and Technology, Syracuse University, 111 College Place, Syracuse, NY 13244, USA.
| | - Jonathan Bortz
- Human Nutrition and Pharma, Balchem Corporation, 52 Sunrise Park Road, New Hampton, NY 10958, USA.
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17
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Hernando N, Wagner CA. Mechanisms and Regulation of Intestinal Phosphate Absorption. Compr Physiol 2018; 8:1065-1090. [PMID: 29978897 DOI: 10.1002/cphy.c170024] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
States of hypo- and hyperphosphatemia have deleterious consequences including rickets/osteomalacia and renal/cardiovascular disease, respectively. Therefore, the maintenance of appropriate plasma levels of phosphate is an essential requirement for health. This control is executed by the collaborative action of intestine and kidney whose capacities to (re)absorb phosphate are regulated by a number of hormonal and metabolic factors, among them parathyroid hormone, fibroblast growth factor 23, 1,25(OH)2 vitamin D3 , and dietary phosphate. The molecular mechanisms responsible for the transepithelial transport of phosphate across enterocytes are only partially understood. Indeed, whereas renal reabsorption entirely relies on well-characterized active transport mechanisms of phosphate across the renal proximal epithelia, intestinal absorption proceeds via active and passive mechanisms, with the molecular identity of the passive component still unknown. The active absorption of phosphate depends mostly on the activity and expression of the sodium-dependent phosphate cotransporter NaPi-IIb (SLC34A2), which is highly regulated by many of the factors, mentioned earlier. Physiologically, the contribution of NaPi-IIb to the maintenance of phosphate balance appears to be mostly relevant during periods of low phosphate availability. Therefore, its role in individuals living in industrialized societies with high phosphate intake is probably less relevant. Importantly, small increases in plasma phosphate, even within normal range, associate with higher risk of cardiovascular disease. Therefore, therapeutic approaches to treat hyperphosphatemia, including dietary phosphate restriction and phosphate binders, aim at reducing intestinal absorption. Here we review the current state of research in the field. © 2017 American Physiological Society. Compr Physiol 8:1065-1090, 2018.
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Affiliation(s)
- Nati Hernando
- National Center for Competence in Research NCCR Kidney.CH, Institute of Physiology, University Zurich-Irchel, Zurich, Switzerland
| | - Carsten A Wagner
- National Center for Competence in Research NCCR Kidney.CH, Institute of Physiology, University Zurich-Irchel, Zurich, Switzerland
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18
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Garcia-Hernandez V, Quiros M, Nusrat A. Intestinal epithelial claudins: expression and regulation in homeostasis and inflammation. Ann N Y Acad Sci 2017; 1397:66-79. [PMID: 28493289 DOI: 10.1111/nyas.13360] [Citation(s) in RCA: 242] [Impact Index Per Article: 34.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2017] [Revised: 03/17/2017] [Accepted: 03/23/2017] [Indexed: 12/31/2022]
Abstract
The intestinal epithelium forms a highly dynamic and selective barrier that controls absorption of fluid and solutes while restricting pathogen access to underlying tissues. Barrier properties are achieved by intercellular junctions that include an apical tight junction (TJ) and subjacent adherens junctions and desmosomes. The TJ tetraspan claudin proteins form pores between epithelial cells to control paracellular fluid and ion movement. In addition to regulation of barrier function, claudin family members control epithelial homeostasis and are expressed in a spatiotemporal manner in the intestinal crypt-luminal axis. This delicate balance of physiologic differential claudin protein expression is altered during mucosal inflammation. Inflammatory mediators influence transcriptional regulation, as well as endocytic trafficking, targeting, and retention of claudins in the TJ. Increased expression of intestinal epithelial claudin-1, -2, and -18 with downregulation of claudin-3, -4, -5, -7, -8, and -12 has been observed in intestinal inflammatory disorders. Such changes in claudin proteins modify the epithelial barrier function in addition to influencing epithelial and mucosal homeostasis. An improved understanding of the regulatory mechanisms that control epithelial claudin proteins will provide strategies to strengthen the epithelial barrier function and restore mucosal homeostasis in inflammatory disorders.
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Affiliation(s)
| | - Miguel Quiros
- Department of Pathology, University of Michigan, Ann Arbor, Michigan
| | - Asma Nusrat
- Department of Pathology, University of Michigan, Ann Arbor, Michigan
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19
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Salomon J, Gaston C, Magescas J, Duvauchelle B, Canioni D, Sengmanivong L, Mayeux A, Michaux G, Campeotto F, Lemale J, Viala J, Poirier F, Minc N, Schmitz J, Brousse N, Ladoux B, Goulet O, Delacour D. Contractile forces at tricellular contacts modulate epithelial organization and monolayer integrity. Nat Commun 2017; 8:13998. [PMID: 28084299 PMCID: PMC5241865 DOI: 10.1038/ncomms13998] [Citation(s) in RCA: 57] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2016] [Accepted: 11/17/2016] [Indexed: 12/31/2022] Open
Abstract
Monolayered epithelia are composed of tight cell assemblies that ensure polarized exchanges. EpCAM, an unconventional epithelial-specific cell adhesion molecule, is assumed to modulate epithelial morphogenesis in animal models, but little is known regarding its cellular functions. Inspired by the characterization of cellular defects in a rare EpCAM-related human intestinal disease, we find that the absence of EpCAM in enterocytes results in an aberrant apical domain. In the course of this pathological state, apical translocation towards tricellular contacts (TCs) occurs with striking tight junction belt displacement. These unusual cell organization and intestinal tissue defects are driven by the loss of actomyosin network homoeostasis and contractile activity clustering at TCs, yet is reversed by myosin-II inhibitor treatment. This study reveals that adequate distribution of cortical tension is crucial for individual cell organization, but also for epithelial monolayer maintenance. Our data suggest that EpCAM modulation protects against epithelial dysplasia and stabilizes human tissue architecture.
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Affiliation(s)
- Julie Salomon
- Cell Adhesion and Mechanics, Institut Jacques Monod, CNRS UMR7592, Paris Diderot University, 75205 Paris, France.,Department of Paediatric Gastroenterology, Hôpital Necker-Enfants Malades, Sorbonne Paris Cité, 75015 Paris, France
| | - Cécile Gaston
- Cell Adhesion and Mechanics, Institut Jacques Monod, CNRS UMR7592, Paris Diderot University, 75205 Paris, France
| | - Jérémy Magescas
- Cell Adhesion and Mechanics, Institut Jacques Monod, CNRS UMR7592, Paris Diderot University, 75205 Paris, France
| | - Boris Duvauchelle
- Morphogenesis, Homoeostasis and Pathologies, Institut Jacques Monod, CNRS UMR7592, Paris Diderot University, 75013 Paris, France
| | - Danielle Canioni
- Department of Paediatric Anatomo-Pathology, Hôpital Necker-Enfants Malades, Sorbonne Paris Cité, 75015 Paris, France
| | - Lucie Sengmanivong
- Membrane Dynamics and Mechanics of Intracellular Signaling Laboratory, Institut Curie-Centre de Recherche, PSL Research University, 75005 Paris, France
| | - Adeline Mayeux
- Cell Adhesion and Mechanics, Institut Jacques Monod, CNRS UMR7592, Paris Diderot University, 75205 Paris, France
| | - Grégoire Michaux
- Institut de Génétique et Développement de Rennes, CNRS UMR6290, 35000 Rennes, France
| | - Florence Campeotto
- Department of Paediatric Gastroenterology, Hôpital Necker-Enfants Malades, Sorbonne Paris Cité, 75015 Paris, France.,Laboratoire de Microbiologie EA 4065, Faculté de Pharmacie, Université Paris Descartes, 75005 Paris, France
| | - Julie Lemale
- Department of Pediatric Nutrition and Gastroenterology, Armand-Trousseau Hospital, Assistance Publique-Hôpitaux de Paris, Institute of Cardiometabolism and Nutrition, Pierre et Marie Curie University, 75012 Paris, France
| | - Jérôme Viala
- Department of Pediatric Gastroenterology, Assistance Publique-Hôpitaux de Paris, Robert Debré Hospital, Université Paris Diderot, Sorbonne Paris Cité, UMR843, 75019 Paris, France
| | - Françoise Poirier
- Morphogenesis, Homoeostasis and Pathologies, Institut Jacques Monod, CNRS UMR7592, Paris Diderot University, 75013 Paris, France
| | - Nicolas Minc
- Cellular Spatial Organization, Institut Jacques Monod, CNRS UMR7592, Paris Diderot University, 75205 Paris, France
| | - Jacques Schmitz
- Department of Paediatric Gastroenterology, Hôpital Necker-Enfants Malades, Sorbonne Paris Cité, 75015 Paris, France
| | - Nicole Brousse
- Department of Paediatric Anatomo-Pathology, Hôpital Necker-Enfants Malades, Sorbonne Paris Cité, 75015 Paris, France
| | - Benoit Ladoux
- Cell Adhesion and Mechanics, Institut Jacques Monod, CNRS UMR7592, Paris Diderot University, 75205 Paris, France.,Mechanobiology Institute, National University of Singapore, Singapore 117411, Singapore
| | - Olivier Goulet
- Department of Paediatric Gastroenterology, Hôpital Necker-Enfants Malades, Sorbonne Paris Cité, 75015 Paris, France
| | - Delphine Delacour
- Cell Adhesion and Mechanics, Institut Jacques Monod, CNRS UMR7592, Paris Diderot University, 75205 Paris, France
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20
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Muto S. Physiological roles of claudins in kidney tubule paracellular transport. Am J Physiol Renal Physiol 2017; 312:F9-F24. [DOI: 10.1152/ajprenal.00204.2016] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2016] [Revised: 10/24/2016] [Accepted: 10/25/2016] [Indexed: 12/30/2022] Open
Abstract
The paracellular pathways in renal tubular epithelia such as the proximal tubules, which reabsorb the largest fraction of filtered solutes and water and are leaky epithelia, are important routes for transepithelial transport of solutes and water. Movement occurs passively via an extracellular route through the tight junction between cells. The characteristics of paracellular transport vary among different nephron segments with leaky or tighter epithelia. Claudins expressed at tight junctions form pores and barriers for paracellular transport. Claudins are from a multigene family, comprising at least 27 members in mammals. Multiple claudins are expressed at tight junctions of individual nephron segments in a nephron segment-specific manner. Over the last decade, there have been advances in our understanding of the structure and functions of claudins. This paper is a review of our current knowledge of claudins, with special emphasis on their physiological roles in proximal tubule paracellular solute and water transport.
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Affiliation(s)
- Shigeaki Muto
- Division of Nephrology, Department of Internal Medicine, Jichi Medical University, Shimotsuke, Tochigi, Japan
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21
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Conrad MP, Piontek J, Günzel D, Fromm M, Krug SM. Molecular basis of claudin-17 anion selectivity. Cell Mol Life Sci 2016; 73:185-200. [PMID: 26194246 PMCID: PMC11108356 DOI: 10.1007/s00018-015-1987-y] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2015] [Revised: 06/23/2015] [Accepted: 07/09/2015] [Indexed: 01/09/2023]
Abstract
Claudin-17 is a paracellular channel-forming tight junction protein. Unlike the cation channels claudin-2 and -15, claudin-17 forms a distinct anion-selective channel. Aim of this study was to determine the molecular basis of channel formation and charge selectivity of this protein. To achieve this, residues located in the extracellular loops (ECL) 1 and 2 of claudin-17 were substituted, preferably those whose charges differed in claudin-17 and in claudin-2 or -15. The respective mutants were stably expressed in MDCK C7 cells and their ability to form charge-selective channels was analyzed by measuring ion permeabilities and transepithelial electrical resistance. The functional data were combined with homology modeling of the claudin-17 protomer using the structure of claudin-15 as template. In ECL1, K65, R31, E48, and E44 were found to be stronger involved in Cldn17 channel function than the clustered R45, R56, R59, and R61. For K65, not only charge but also stereochemical properties were crucial for formation of the anion-selective channel. In ECL2, both Y149 and H154 were found to contribute to constitution of the anion channel in a distinct manner. In conclusion, we provide insight into the molecular mechanism of the formation of charge- and size-selective paracellular ion channels. In detail, we propose a hydrophilic furrow in the claudin-17 protomer spanning from a gap between the ends of TM2 and TM3 along R31, E48, and Y67 to a gap between K65 and S68 lining the anion channel.
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Affiliation(s)
- Marcel P Conrad
- Institute of Clinical Physiology, Charité, Universitätsmedizin Berlin, Campus Benjamin Franklin, Hindenburgdamm 30, 12203, Berlin, Germany
| | - Jörg Piontek
- Institute of Clinical Physiology, Charité, Universitätsmedizin Berlin, Campus Benjamin Franklin, Hindenburgdamm 30, 12203, Berlin, Germany
| | - Dorothee Günzel
- Institute of Clinical Physiology, Charité, Universitätsmedizin Berlin, Campus Benjamin Franklin, Hindenburgdamm 30, 12203, Berlin, Germany
| | - Michael Fromm
- Institute of Clinical Physiology, Charité, Universitätsmedizin Berlin, Campus Benjamin Franklin, Hindenburgdamm 30, 12203, Berlin, Germany
| | - Susanne M Krug
- Institute of Clinical Physiology, Charité, Universitätsmedizin Berlin, Campus Benjamin Franklin, Hindenburgdamm 30, 12203, Berlin, Germany.
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22
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Garg S, Zheng J, Wang J, Authier S, Pouliot M, Hauer-Jensen M. Segmental Differences in Radiation-Induced Alterations of Tight Junction-Related Proteins in Non-Human Primate Jejunum, Ileum and Colon. Radiat Res 2015; 185:50-9. [PMID: 26720804 DOI: 10.1667/rr14157.1] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Dysfunction of the intestinal epithelial barrier and leakage of luminal antigens and bacteria across the barrier have been linked to various human diseases. Intestinal permeability is regulated by intercellular structures, termed "tight junction" (Tj), which are disrupted after total-body irradiation (TBI). In this study, we investigated radiation-induced alterations in Tj-related proteins in the jejunum, ileum and colon of a non-human primate (NHP) model. NHPs were total-body irradiated with 6.7 and 7.4 Gy and intestines were procured at day 4, 7 and 12. Radiation exposure was found to induce significant increases in claudin-10 mRNA early (day 4) in all three gut segments and claudin-4 mRNA levels were repressed through day 12. TNF-alpha was highly induced in the jejunum and colon at early time points, but little induction was found in the ileum. Claudin-1 was induced only in the colon on day 4 postirradiation. Unlike the colon and jejunum, the ileum levels of claudin-7 were significantly downregulated through day 12 postirradiation. Western blot analysis revealed increased levels of claudin-2 on day 4 and of JAM-1 on day 7 postirradiation in all three gut segments. E-cadherin was downregulated on day 4 postirradiation in all segments, but remained reduced in the jejunum only until day 12. Taken together, these data suggest that exposure to radiation causes segment-specific alterations in the expression of Tj-related proteins. Interruption of Tjs may be a key factor contributing to injury to the intestinal mucosal barrier and increased intestinal permeability.
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Affiliation(s)
- Sarita Garg
- a Department of Pharmaceutical Sciences, Division of Radiation Health, University of Arkansas for Medical Sciences, Little Rock, Arkansas
| | - Junying Zheng
- a Department of Pharmaceutical Sciences, Division of Radiation Health, University of Arkansas for Medical Sciences, Little Rock, Arkansas
| | - Junru Wang
- a Department of Pharmaceutical Sciences, Division of Radiation Health, University of Arkansas for Medical Sciences, Little Rock, Arkansas
| | | | | | - Martin Hauer-Jensen
- a Department of Pharmaceutical Sciences, Division of Radiation Health, University of Arkansas for Medical Sciences, Little Rock, Arkansas;,c Surgical Service, Central Arkansas Veterans Healthcare System, Little Rock, Arkansas
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Necrotizing enterocolitis in a mouse model leads to widespread renal inflammation, acute kidney injury, and disruption of renal tight junction proteins. Pediatr Res 2015; 78:527-32. [PMID: 26270572 PMCID: PMC4628581 DOI: 10.1038/pr.2015.146] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/21/2015] [Accepted: 05/06/2015] [Indexed: 11/25/2022]
Abstract
BACKGROUND Necrotizing enterocolitis (NEC) is a devastating condition affecting premature infants and leads to high mortality and chronic morbidity. Severe form of NEC is associated with acute renal failure, fluid imbalance, hyponatremia, and acidosis. We investigated the effect of NEC on tight junction (TJ) proteins in kidneys using a NEC mouse model to investigate the basis for the observed renal dysfunction. METHODS NEC was induced in C57BL/6 mice by formula feeding and subjecting them to periods of hypoxia and cold stress. NEC was confirmed by gross and histological examination. We studied various markers of inflammation in kidneys and investigated changes in expression of several TJ proteins and AQP2 using immunofluorecent staining and western blotting. RESULTS We found markedly increased expression of NFκB, TGFβ, and ERK1/2 along with claudin-1, -2, -3, -4, -8, and AQP-2 in NEC kidneys. The membrane localization of claudin-2 was altered in the NEC kidneys and its immunostaining signal at TJ was disrupted. CONCLUSION NEC led to a severe inflammatory response not only in the gut but also in the kidneys. NEC increased expression of several TJ proteins and caused disruption of claudin-2 in renal tubules. These observed changes can help explain some of the clinical findings observed in NEC.
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24
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Assembly and function of claudins: Structure–function relationships based on homology models and crystal structures. Semin Cell Dev Biol 2015; 42:3-12. [DOI: 10.1016/j.semcdb.2015.04.010] [Citation(s) in RCA: 76] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2015] [Revised: 04/28/2015] [Accepted: 04/29/2015] [Indexed: 01/12/2023]
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25
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Transcriptional regulators of claudins in epithelial tight junctions. Mediators Inflamm 2015; 2015:219843. [PMID: 25948882 PMCID: PMC4407569 DOI: 10.1155/2015/219843] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2014] [Revised: 09/22/2014] [Accepted: 10/03/2014] [Indexed: 02/06/2023] Open
Abstract
Human gastrointestinal tract is covered by a monolayer of specialized epithelial cells that constitute a protective barrier surface to external toxic and infectious agents along with metabolic and digestive functions. Intercellular junctions, among epithelial cells, such as desmosomes, adherens, gap, and tight junctions (TJs), not only provide mechanical integrity but also limit movement of molecules across the monolayer. TJ is a complex structure composed of approximately 35 different proteins that interact with each other at the apical side of two adjacent epithelial cells. Claudin family proteins are important members of TJ with so far 24 known isoforms in different species. Claudins are structural proteins of TJ that help to control the paracellular movement by forming fence and barrier across the epithelial monolayer. Altered function of claudins is implicated in different form of cancers, inflammatory bowel diseases (IBDs), and leaky diarrhea. Based on their significant role in the molecular architecture of TJ, diversity, and disease association, further understanding about claudin family proteins and their genetic/epigenetic regulators is indispensable.
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26
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Abstract
Claudins are tight-junction membrane proteins that function as both pores and barriers in the paracellular pathway in epithelial cells. In the kidney, claudins determine the permeability and selectivity of different nephron segments along the renal tubule. In the proximal tubule, claudins have a role in the bulk reabsorption of salt and water. In the thick ascending limb, claudins are important for the reabsorption of calcium and magnesium and are tightly regulated by the calcium-sensing receptor. In the distal nephron, claudins need to form cation barriers and chloride pores to facilitate electrogenic sodium reabsorption and potassium and acid secretion. Aldosterone and the with-no-lysine (WNK) proteins likely regulate claudins to fine-tune distal nephron salt transport. Genetic mutations in claudin-16 and -19 cause familial hypomagnesemic hypercalciuria with nephrocalcinosis, whereas polymorphisms in claudin-14 are associated with kidney stone risk. It is likely that additional roles for claudins in the pathogenesis of other types of kidney diseases have yet to be uncovered.
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Affiliation(s)
- Alan S L Yu
- Division of Nephrology and Hypertension, and the Kidney Institute, University of Kansas Medical Center, Kansas City, Kansas
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27
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Abstract
The imbalance between bone formation and resorption during bone remodeling has been documented to be a major factor in the pathogenesis of osteoporosis. Recent evidence suggests a significant role for the tight junction proteins, Claudins (Cldns), in the regulation of bone remodeling processes. In terms of function, whereas Cldns act "canonically" as key determinants of paracellular permeability, there is considerable recent evidence to suggest that Cldns also participate in cell signaling, ie, a "noncanonical function". To this end, Cldns have been shown to regulate cell proliferation, differentiation, and gene expression in a variety of cell types. The present review will discuss Cldns' structure, their expression profile, regulation of expression, and their canonical and non- canonical functions in general with special emphasis on bone cells. In order to shed light on the noncanonical functions of Cldns in bone, we will highlight the role of Cldn-18 in regulating bone resorption and osteoclast differentiation. Collectively, we hope to provide a framework for guiding future research on understanding how Cldns modulate osteoblast and osteoclast function and overall bone homeostasis. Such studies should provide valuable insights into the pathogenesis of osteoporosis, and may highlight Cldns as novel targets for the diagnosis and therapeutic management of osteoporosis.
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Affiliation(s)
- Fatima Z Alshbool
- Musculoskeletal Disease Center (F.Z.A., S.M.), Jerry L. Pettis VA Medical Center, Loma Linda, CA 92357; Departments of Medicine (S.M.), Biochemistry (S.M.), Physiology (S.M.), and Pharmacology (F.Z.A., S.M.), Loma Linda University, Loma Linda, California 92354
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Tsujiwaki M, Murata M, Takasawa A, Hiratsuka Y, Fukuda R, Sugimoto K, Ono Y, Nojima M, Tanaka S, Hirata K, Kojima T, Sawada N. Aberrant expression of claudin-4 and -7 in hepatocytes in the cirrhotic human liver. Med Mol Morphol 2014; 48:33-43. [PMID: 24737165 DOI: 10.1007/s00795-014-0074-z] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2014] [Accepted: 03/18/2014] [Indexed: 12/16/2022]
Abstract
The liver comprises hepatocytes and non-parenchymal cells such as bile duct epithelial cells. Claudin-4 and -7 are not expressed in hepatocytes under physiological conditions. It was reported that claudin-7 increased in human pulmonary fibroses. We therefore investigated claudin-4 and -7 expressions in human cirrhotic livers, in which hepatocyte proliferation is severely delayed. We examined liver tissues from 50 patients with liver tumors. The expression of claudin-4 and -7 in hepatocytes significantly increased with the grade of fibrosis, not with inflammatory activity, in the liver tissues of chronic hepatitis. The number of claudin-4- and -7-positive cells observed was greater than that of alpha-fetoprotein-positive hepatic progenitor cells. In primary cultures of mouse hepatocytes, the expression of claudin-4 and -7 was not induced by treatment with proinflammatory cytokines. In immunohistochemical analysis of liver tissues of 3,5-diethoxycarbonyl-1,4-dihydrocollidine-treated mice and primary cultures of mouse hepatocytes, the expression of claudin-4 and -7 increased with proliferation of progenitor cells. However, the claudin-4- and -7-positive cells were not always progenitor cells. Thus, claudin-4 and -7 were observed in hepatocytes of severely damaged mouse and human livers. These findings suggest that claudin-4- and -7-positive hepatocytes may exist during the process of differentiation from progenitor cells into mature hepatocytes.
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Affiliation(s)
- Mitsuhiro Tsujiwaki
- Department of Pathology, Sapporo Medical University School of Medicine, S1. W17, Sapporo, 060-8556, Japan
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29
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Hwang I, Yang H, Kang HS, Ahn CH, Lee GS, Hong EJ, An BS, Jeung EB. Spatial expression of claudin family members in various organs of mice. Mol Med Rep 2014; 9:1806-12. [PMID: 24626855 DOI: 10.3892/mmr.2014.2031] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2013] [Accepted: 02/17/2014] [Indexed: 11/05/2022] Open
Abstract
Claudins (CLDNs) are tetraspan transmembrane proteins, which are components of tight junctions. The CLDN family is composed of 27 members that are responsible for paracellular transport and certain CLDNs form charge-selective ion channels. CLDNs have two extracellular loops, and the charge of the first extracellular loop determines the ion selectivity of each CLDN. Although the expression and function of each CLDN have been previously investigated, the distribution of CLDNs in various target organs remains to be determined. In the present study, the tissue-specific mRNA distribution of CLDNs (1-5, 7-8, 10a and b, 11-12, 14-17 and 19) in the duodenum, ileum, colon, kidney, liver and lung were defined. Among the tested CLDNs, CLDN1, 2, 12 and 16 were selected for further investiagtion. It was observed that CLDN1, CLDN2 and CLDN12 transcripts and proteins were particularly abundant in the investigated organs. Notably, immune-reactive CLDN16 was detected in a tissue-specific manner and shown in the renal tubules and portal vein. The tested CLDNs were localized to intercellular apical junctions in the epithelium of the intestine, renal tubule and bronchus. Based on this novel information, the presence of several types of CLDNs is of interest as CLDNs may promote or dampen the paracellular diffusion of specific ions.
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Affiliation(s)
- Inho Hwang
- Laboratory of Veterinary Biochemistry and Molecular Biology, College of Veterinary Medicine, Chungbuk National University, Cheongju, Chungbuk 361‑763, Republic of Korea
| | - Hyun Yang
- Laboratory of Veterinary Biochemistry and Molecular Biology, College of Veterinary Medicine, Chungbuk National University, Cheongju, Chungbuk 361‑763, Republic of Korea
| | - Hong-Seok Kang
- Laboratory of Veterinary Biochemistry and Molecular Biology, College of Veterinary Medicine, Chungbuk National University, Cheongju, Chungbuk 361‑763, Republic of Korea
| | - Chang-Hwan Ahn
- Laboratory of Veterinary Biochemistry and Molecular Biology, College of Veterinary Medicine, Chungbuk National University, Cheongju, Chungbuk 361‑763, Republic of Korea
| | - Geun-Shik Lee
- Laboratory of Veterinary Physiology, College of Veterinary Medicine, Kangwon National University, Chuncheon, Gangwon 200‑701, Republic of Korea
| | - Eui-Ju Hong
- Laboratory of Veterinary Biochemistry and Molecular Biology, College of Veterinary Medicine, Chungbuk National University, Cheongju, Chungbuk 361‑763, Republic of Korea
| | - Beum-Soo An
- Department of Biomaterials Science, College of National Resources and Life Science, Pusan National University, Miryang, Pusan 627‑706, Republic of Korea
| | - Eui-Bae Jeung
- Laboratory of Veterinary Biochemistry and Molecular Biology, College of Veterinary Medicine, Chungbuk National University, Cheongju, Chungbuk 361‑763, Republic of Korea
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30
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Abstract
Epithelial transport relies on the proper function and regulation of the tight junction (TJ), other-wise uncontrolled paracellular leakage of solutes and water would occur. They also act as a fence against mixing of membrane proteins of the apical and basolateral side. The proteins determining paracellular transport consist of four transmembrane regions, intracellular N and C terminals, one intracellular and two extracellular loops (ECLs). The ECLs interact laterally and with counterparts of the neighboring cell and by this achieve a general sealing function. Two TJ protein families can be distinguished, claudins, comprising 27 members in mammals, and TJ-associated MARVEL proteins (TAMP), comprising occludin, tricellulin, and MarvelD3. They are linked to a multitude of TJ-associated regulatory and scaffolding proteins. The major TJ proteins are classified according to the physiological role they play in enabling or preventing paracellular transport. Many TJ proteins have sealing functions (claudins 1, 3, 5, 11, 14, 19, and tricellulin). In contrast, a significant number of claudins form channels across TJs which feature selectivity for cations (claudins 2, 10b, and 15), anions (claudin-10a and -17), or are permeable to water (claudin-2). For several TJ proteins, function is yet unclear as their effects on epithelial barriers are inconsistent (claudins 4, 7, 8, 16, and occludin). TJs undergo physiological and pathophysiological regulation by altering protein composition or abundance. Major pathophysiological conditions which involve changes in TJ protein composition are (1) effects of pathogens binding to TJ proteins, (2) altered TJ protein composition during inflammation and infection, and (3) altered TJ protein expression in cancers.
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Affiliation(s)
- Dorothee Günzel
- Institute of Clinical Physiology, Charité, Universtätsmedizin Berlin, Campus Benjamin Franklin, Freie Universität/Humboldt-Universität, Berlin, Germany
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31
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Hu YJ, Wang YD, Tan FQ, Yang WX. Regulation of paracellular permeability: factors and mechanisms. Mol Biol Rep 2013; 40:6123-42. [PMID: 24062072 DOI: 10.1007/s11033-013-2724-y] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2012] [Accepted: 09/14/2013] [Indexed: 12/20/2022]
Abstract
Epithelial permeability is composed of transcellular permeability and paracellular permeability. Paracellular permeability is controlled by tight junctions (TJs). Claudins and occludin are two major transmembrane proteins in TJs, which directly determine the paracellular permeability to different ions or large molecules. Intracellular signaling pathways including Rho/Rho-associated protein kinase, protein kinase Cs, and mitogen-activated protein kinase, modulate the TJ proteins to affect paracellular permeability in response for diverse stimuli. Cytokines, growth factors and hormones in organism can regulate the paracellular permeability via signaling pathway. The transcellular transporters such as Na-K-ATPase, Na(+)-coupled transporters and chloride channels, can interact with paracellular transport and regulate the TJs. In this review, we summarized the factors affecting paracellular permeability and new progressions of the related mechanism in recent studies, and pointed out further research areas.
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Affiliation(s)
- Yan-Jun Hu
- Department of Reproductive Endocrinology, Women's Hospital, School of Medicine, Zhejiang University, Hangzhou, 310006, People's Republic of China
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Abstract
Calcium nephrolithiasis is a common condition. Family-based genetic linkage studies and genome-wide association studies (GWASs) have uncovered a run of important candidate genes involved in renal Ca(++) disorders and kidney stone diseases. The susceptible genes include NKCC2, ROMK and ClCkb/Barttin that underlie renal salt excretion; claudin-14, -16 and -19 that underlie renal Ca(++) excretion; and CaSR that provides a sensing mechanism for the kidney to regulate salt, water and Ca(++) homeostasis. Biological and physiological analyses have revealed the cellular mechanism for transepithelial Ca(++) transport in the kidney that depends on the concerted action of these gene products. Although the individual pathogenic weight of the susceptible genes in nephrolithiasis remains unclear, perturbation of their expression or function compromises the different steps within the integrated pathway for Ca(++) reabsorption, providing a physiological basis for diagnosing and managing kidney stone diseases.
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Affiliation(s)
- Jianghui Hou
- Washington University Renal Division, St. Louis, MO 63110, USA.
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33
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Gonçalves A, Ambrósio AF, Fernandes R. Regulation of claudins in blood-tissue barriers under physiological and pathological states. Tissue Barriers 2013; 1:e24782. [PMID: 24665399 PMCID: PMC3867514 DOI: 10.4161/tisb.24782] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2013] [Revised: 04/18/2013] [Accepted: 04/23/2013] [Indexed: 01/01/2023] Open
Abstract
Claudins are pivotal building blocks of tight junctions that form the paracellular barrier in epithelia and endothelia. In mammals, claudins are a 27-gene family that encodes tetraspan membrane proteins, playing a crucial role in the formation and integrity of tight junctions and regulate the barrier function. Claudin isoforms are expressed in a tissue- and/or developmental stage-dependent manner. A growing body of evidence indicates that pathological states characterized by neuroinflammation, such as Alzheimer disease, multiple sclerosis, diabetic retinopathy and retinopathy of prematurity share a common feature: the barrier breakdown. This review aims integrating and summarizing the most relevant and recent work developed in the field of claudins, with particular attention to their role in blood-brain and blood-retinal barriers, as well as describing their regulation in the aforementioned human diseases.
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Affiliation(s)
- Andreia Gonçalves
- Laboratory of Pharmacology and Experimental Therapeutics; IBILI - Institute for Biomedical Imaging and Life Sciences; Faculty of Medicine; University of Coimbra; Coimbra, Portugal
| | - António Francisco Ambrósio
- Centre of Ophthalmology and Vision Sciences; IBILI; Faculty of Medicine; University of Coimbra; Coimbra, Portugal ; AIBILI; Coimbra, Portugal
| | - Rosa Fernandes
- Laboratory of Pharmacology and Experimental Therapeutics; IBILI - Institute for Biomedical Imaging and Life Sciences; Faculty of Medicine; University of Coimbra; Coimbra, Portugal ; Centre of Ophthalmology and Vision Sciences; IBILI; Faculty of Medicine; University of Coimbra; Coimbra, Portugal
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34
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Abstract
Claudins are tight junction membrane proteins that are expressed in epithelia and endothelia and form paracellular barriers and pores that determine tight junction permeability. This review summarizes our current knowledge of this large protein family and discusses recent advances in our understanding of their structure and physiological functions.
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Affiliation(s)
- Dorothee Günzel
- Department of Clinical Physiology, Charité, Campus Benjamin Franklin, Berlin, Germany
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35
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Bhattacharya J, Matthay MA. Regulation and repair of the alveolar-capillary barrier in acute lung injury. Annu Rev Physiol 2013; 75:593-615. [PMID: 23398155 DOI: 10.1146/annurev-physiol-030212-183756] [Citation(s) in RCA: 223] [Impact Index Per Article: 20.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Considerable progress has been made in understanding the basic mechanisms that regulate fluid and protein exchange across the endothelial and epithelial barriers of the lung under both normal and pathological conditions. Clinically relevant lung injury occurs most commonly from severe viral and bacterial infections, aspiration syndromes, and severe shock. The mechanisms of lung injury have been identified in both experimental and clinical studies. Recovery from lung injury requires the reestablishment of an intact endothelial barrier and a functional alveolar epithelial barrier capable of secreting surfactant and removing alveolar edema fluid. Repair mechanisms include the participation of endogenous progenitor cells in strategically located niches in the lung. Novel treatment strategies include the possibility of cell-based therapy that may reduce the severity of lung injury and enhance lung repair.
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Affiliation(s)
- Jahar Bhattacharya
- Division of Pulmonary Allergy and Critical Care, Department of Medicine, Columbia University Medical Center, New York, NY 10032, USA.
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Suzuki T. Regulation of intestinal epithelial permeability by tight junctions. Cell Mol Life Sci 2013; 70:631-59. [PMID: 22782113 PMCID: PMC11113843 DOI: 10.1007/s00018-012-1070-x] [Citation(s) in RCA: 844] [Impact Index Per Article: 76.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2012] [Revised: 06/19/2012] [Accepted: 06/21/2012] [Indexed: 12/13/2022]
Abstract
The gastrointestinal epithelium forms the boundary between the body and external environment. It effectively provides a selective permeable barrier that limits the permeation of luminal noxious molecules, such as pathogens, toxins, and antigens, while allowing the appropriate absorption of nutrients and water. This selective permeable barrier is achieved by intercellular tight junction (TJ) structures, which regulate paracellular permeability. Disruption of the intestinal TJ barrier, followed by permeation of luminal noxious molecules, induces a perturbation of the mucosal immune system and inflammation, and can act as a trigger for the development of intestinal and systemic diseases. In this context, much effort has been taken to understand the roles of extracellular factors, including cytokines, pathogens, and food factors, for the regulation of the intestinal TJ barrier. Here, I discuss the regulation of the intestinal TJ barrier together with its implications for the pathogenesis of diseases.
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Affiliation(s)
- Takuya Suzuki
- Department of Biofunctional Science and Technology, Graduate School of Biosphere Science, Hiroshima University, 1-4-4, Kagamiyama, Higashi-Hiroshima, 739-8528, Japan.
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Thongon N, Krishnamra N. Apical acidity decreases inhibitory effect of omeprazole on Mg(2+) absorption and claudin-7 and -12 expression in Caco-2 monolayers. Exp Mol Med 2012; 44:684-93. [PMID: 22940736 PMCID: PMC3509185 DOI: 10.3858/emm.2012.44.11.077] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Clinical studies reported hypomagnesaemia in long-term omeprazole usage that was probably due to intestinal Mg(2+) wasting. Our previous report demonstrated the inhibitory effect of omeprazole on passive Mg(2+) transport across Caco-2 monolayers. The present study aimed to identify the underlying mechanism of omeprazole suppression of passive Mg(2+) absorption. By using Caco-2 monolayers, we demonstrated a potent inhibitory effect of omeprazole on passive Mg(2+), but not Ca(2+), transport across Caco-2 monolayers. Omeprazole shifted the %maximum passive Mg(2+) transport-Mg(2+) concentration curves to the right, and increased the half maximal effective concentration of those dose-response curves, indicating a lower Mg(2+) affinity of the paracellular channel. By continually monitoring the apical pH, we showed that omeprazole suppressed apical acid accumulation. Neomycin and spermine had no effect on passive Mg(2+) transport of either control or omeprazole treated monolayers, indicating that omeprazole suppressed passive Mg(2+) transport in a calcium sensing receptor (CaSR)-independent manner. The results of western blot analysis showed that omeprazole significantly suppressed claudin (Cldn)-7 and -12, but not Cldn-2, expression in Caco-2 cells. By using apical solution of pH 5.5, 6.0, 6.5, and 7.0, we found that apical acidity markedly increased passive Mg(2+) transport, Mg(2+) affinity of the paracellular channel, and Cldn-7 and -12 expression in Caco-2 monolayers. Apical acidity abolished the inhibitory effect of omeprazole on passive Mg(2+) transport and Cldn-7 and -12 expression. Our results provided the evidence for the regulation of intestinal passive Mg(2+) absorption by luminal acidity-induced increase in Cldn-7 and -12 expression.
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Affiliation(s)
- Narongrit Thongon
- Faculty of Allied Health Sciences Burapha University Chonburi 20131, Thailand.
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Veshnyakova A, Krug SM, Mueller SL, Piontek J, Protze J, Fromm M, Krause G. Determinants contributing to claudin ion channel formation. Ann N Y Acad Sci 2012; 1257:45-53. [PMID: 22671588 DOI: 10.1111/j.1749-6632.2012.06566.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Pore-forming properties of claudins (Cld) are likely defined by residues of their first extracellular loop (ECL1). Detailed mechanisms are unclear. MDCK cells overexpressing FLAG-Cld-1 wild-type and mutants were characterized by transepithelial resistance (TER) and ion permeability measurements. Replacing ECL1 residues of sealing Cld-1 by corresponding Cld-2 residues we aimed to identify new determinants responsible for sealing and/or pore formation. We found that E48K and S53E substitutions in human Cld-1 strongly reduced TER and increased permeability for Na(+) and Cl(-) . In contrast, K65D, D68S, and other single substitutions showed no significant change of TER and permeability for Na(+) and Cl(-) . Double substitution S53E/K65D did not change TER and ion permeability, whereas S53E/D68S decreased TER, albeit weaker than S53E. Ratio of permeabilities for Na(+) and Cl(-) revealed no clear charge specificity of the pore induced by S53E or S53E/D68S in Cld-1, suggesting that primarily S53 and potentially D68 in Cld-1 are involved in sealing of the paracellular cleft and that charge-unselective pores may be induced by substituting S53E.
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39
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Abstract
Claudins are tight junction membrane proteins that regulate paracellular permeability of renal epithelia to small ions, solutes, and water. Claudins interact within the cell membrane and between neighboring cells to form tight junction strands and constitute both the paracellular barrier and the pore. The first extracellular domain of claudins is thought to be the pore-lining domain and contains the determinants of charge selectivity. Multiple claudins are expressed in different nephron segments; such differential expression likely determines the permeability properties of each segment. Recent evidence has identified claudin-2 as constituting the cation-reabsorptive pathway in the proximal tubule; claudin-14, -16, and -19 as forming a complex that regulates calcium transport in the thick ascending limb of the loop of Henle; and claudin-4, -7, and -8 as determinants of collecting duct chloride permeability. Mutations in claudin-16 and -19 cause familial hypercalciuric hypomagnesemia with nephrocalcinosis. The roles of other claudins in kidney diseases remain to be fully elucidated.
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Affiliation(s)
- Jianghui Hou
- Renal Division, Washington University, St. Louis, Missouri 63110, USA
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Engelund MB, Yu ASL, Li J, Madsen SS, Færgeman NJ, Tipsmark CK. Functional characterization and localization of a gill-specific claudin isoform in Atlantic salmon. Am J Physiol Regul Integr Comp Physiol 2012; 302:R300-11. [PMID: 21975646 PMCID: PMC3349389 DOI: 10.1152/ajpregu.00286.2011] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2011] [Accepted: 10/05/2011] [Indexed: 11/22/2022]
Abstract
Claudins are the major determinants of paracellular epithelial permeability in multicellular organisms. In Atlantic salmon (Salmo salar L.), we previously found that mRNA expression of the abundant gill-specific claudin 30 decreases during seawater (SW) acclimation, suggesting that this claudin is associated with remodeling of the epithelium during salinity change. This study investigated localization, protein expression, and function of claudin 30. Confocal microscopy showed that claudin 30 protein was located at cell-cell interfaces in the gill filament in SW- and fresh water (FW)-acclimated salmon, with the same distribution, overall, as the tight junction protein ZO-1. Claudin 30 was located at the apical tight junction interface and in cell membranes deeper in the epithelia. Colocalization with the α-subunit of the Na(+)-K(+)-ATPase was negligible, suggesting limited association with mitochondria-rich cells. Immunoblotting of gill samples showed lower claudin 30 protein expression in SW than FW fish. Retroviral transduction of claudin 30 into Madin-Darby canine kidney cells resulted in a decreased conductance of 19%. The decreased conductance correlated with a decreased permeability of the cell monolayer to monovalent cations, whereas permeability to chloride was unaffected. Confocal microscopy revealed that claudin 30 was expressed in the lateral membrane, as well as in tight junctions of Madin-Darby canine kidney cells, thereby paralleling the findings in the native gill. This study suggests that claudin 30 functions as a cation barrier between pavement cells in the gill and also has a general role in cell-cell adhesion in deeper layers of the epithelium.
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Affiliation(s)
- M. B. Engelund
- Institutes of Biology and
- Division of Nephrology, Department of Medicine, Keck School of Medicine, University of Southern California, Los Angeles, California; and
| | - A. S. L. Yu
- Division of Nephrology, Department of Medicine, Keck School of Medicine, University of Southern California, Los Angeles, California; and
| | - J. Li
- Division of Nephrology, Department of Medicine, Keck School of Medicine, University of Southern California, Los Angeles, California; and
| | | | - N. J. Færgeman
- Biochemistry and Molecular Biology, University of Southern Denmark, Odense, Denmark
| | - C. K. Tipsmark
- Institutes of Biology and
- Department of Biological Sciences, University of Arkansas, Fayetteville, Arkansas
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Abstract
The physiology of paracellular permeation of ions and solutes in the kidney is pivotally important but poorly understood. Claudins are the key components of the paracellular pathway. Defects in claudin function result in a broad range of renal diseases, including hypomagnesemia, hypercalciuria and nephrolithiasis. This review describes recent findings on the physiological function of claudins underlying paracellular transport mechanisms with a focus on renal Ca(2+) handling. We have uncovered a molecular mechanism underlying paracellular Ca(2+) transport in the thick ascending limb of Henle (TAL) that involves the functional interplay of three important claudin genes: claudin-14, -16 and -19, all of which are associated with human kidney diseases with hypercalciuria, nephrolithiasis and bone mineral loss. The Ca(2+) sensing receptor (CaSR) signaling in the kidney has long been a mystery. By analyzing small non-coding RNA molecules in the kidney, we have uncovered a novel microRNA based signaling pathway downstream of CaSR that directly regulates claudin-14 gene expression and establishes the claudin-14 molecule as a key regulator for renal Ca(2+) homeostasis. The molecular cascade of CaSR-microRNAs-claudins forms a regulatory loop to maintain proper Ca(2+) homeostasis in the kidney.
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Affiliation(s)
- Jianghui Hou
- Renal Division, Washington University, St. Louis, MO, USA.
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42
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Probiotic bacteria induce maturation of intestinal claudin 3 expression and barrier function. THE AMERICAN JOURNAL OF PATHOLOGY 2011; 180:626-35. [PMID: 22155109 DOI: 10.1016/j.ajpath.2011.10.025] [Citation(s) in RCA: 246] [Impact Index Per Article: 18.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/06/2011] [Revised: 10/04/2011] [Accepted: 10/31/2011] [Indexed: 02/08/2023]
Abstract
An immature intestinal epithelial barrier may predispose infants and children to many intestinal inflammatory diseases, such as infectious enteritis, inflammatory bowel disease, and necrotizing enterocolitis. Understanding the factors that regulate gut barrier maturation may yield insight into strategies to prevent these intestinal diseases. The claudin family of tight junction proteins plays an important role in regulating epithelial paracellular permeability. Previous reports demonstrate that rodent intestinal barrier function matures during the first 3 weeks of life. We show that murine paracellular permeability markedly decreases during postnatal maturation, with the most significant change occurring between 2 and 3 weeks. Here we report for the first time that commensal bacterial colonization induces intestinal barrier function maturation by promoting claudin 3 expression. Neonatal mice raised on antibiotics or lacking the toll-like receptor adaptor protein MyD88 exhibit impaired barrier function and decreased claudin 3 expression. Furthermore, enteral administration of either live or heat-killed preparations of the probiotic Lactobacillus rhamnosus GG accelerates intestinal barrier maturation and induces claudin 3 expression. However, live Lactobacillus rhamnosus GG increases mortality. Taken together, these results support a vital role for intestinal flora in the maturation of intestinal barrier function. Probiotics may prevent intestinal inflammatory diseases by regulating intestinal tight junction protein expression and barrier function. The use of heat-killed probiotics may provide therapeutic benefit while minimizing adverse effects.
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Martin-Martin N, Dan Q, Amoozadeh Y, Waheed F, McMorrow T, Ryan MP, Szászi K. RhoA and Rho kinase mediate cyclosporine A and sirolimus-induced barrier tightening in renal proximal tubular cells. Int J Biochem Cell Biol 2011; 44:178-88. [PMID: 22062948 DOI: 10.1016/j.biocel.2011.10.014] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2011] [Revised: 09/29/2011] [Accepted: 10/24/2011] [Indexed: 10/15/2022]
Abstract
The regulation and maintenance of the paracellular transport in renal tubular epithelia is vital for kidney functions. Combination of the immunosuppressant drugs cyclosporine A (CsA) and sirolimus (SRL) exerts powerful immunosuppression, but also causes nephrotoxicity. We have previously shown that CsA and SRL elevate transepithelial resistance (TER) in kidney tubular cells partly through MEK/ERK1/2. In this work we examined the hypothesis that the RhoA pathway may also be mediating effects of CsA and SRL. We show that CsA and the CsA/SRL combination activated RhoA, induced cofilin phosphorylation and promoted stress fiber generation. The Rho kinase (ROK) inhibitor, Y27632, prevented CsA and CsA/SRL-induced cofilin phosphorylation and actin remodelling, reduced the TER increase and prevented the rise in claudin-7 levels caused by the drugs. Expression of the exchange factor GEF-H1/lfc was elevated in cells treated with CsA and CsA/SRL. GEF-H1 silencing inhibited RhoA activation by ≈50%, and potently reduced cofilin phosphorylation and stress fiber formation induced by CsA and CsA/SRL. However, GEF-H1 downregulation did not prevent the TER change. Thus the Rho/Rho kinase pathway was involved in mediating CsA and CsA/SRL-induced cytoskeleton rearrangement and TER changes via claudin-7 expression. Our data however point to differential regulation of Rho activation involved in central cytoskeleton remodelling, that is GEF-H1-dependent and junctional permeability that does not require GEF-H1.
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Affiliation(s)
- Natalia Martin-Martin
- UCD School of Biomolecular and Biomedical Science, UCD Conway Institute, University College Dublin, Belfield, Dublin 4, Ireland
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Muto S, Furuse M, Kusano E. Claudins and renal salt transport. Clin Exp Nephrol 2011; 16:61-7. [PMID: 22038258 DOI: 10.1007/s10157-011-0491-4] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2010] [Accepted: 01/03/2011] [Indexed: 11/25/2022]
Abstract
Tight junctions (TJs) are the most apical component of junctional complexes and regulate the movement of electrolytes and solutes by the paracellular pathway across epithelia. The defining ultrastructural features of TJs are strands of transmembrane protein particles that adhere to similar strands on adjacent cells. These strands are mainly composed of linearly polymerized integral membrane proteins called claudins. Claudins comprise a multigene family consisting of more than 20 members in mammals. Recent work has shown that claudins form barriers, determined by the paracellular electrical resistance and charge selectivity, and pores in the TJ strands. The paracellular pathways in renal tubular epithelia such as the proximal tubule, which reabsorbs the largest fraction of filtered NaCl and water, are important routes for the transport of electrolytes and water. Their transport characteristics vary among different nephron segments. Multiple claudins are expressed at TJs of individual nephron segments in a nephron segment-specific manner. Among them, claudin-2 is highly expressed at TJs of proximal tubules, which are leaky epithelia. Overexpression and knockdown of claudin-2 in epithelial cell lines, and knockout of the claudin-2 gene in mice, have demonstrated that claudin-2 forms high-conductance cation-selective pores in the proximal tubule. Here, we review the renal physiology of paracellular transport and the physiological roles of claudins in kidney function, especially claudin-2 and proximal tubule paracellular NaCl transport.
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Affiliation(s)
- Shigeaki Muto
- Division of Nephrology, Department of Internal Medicine, Jichi Medical University, Shimotsuke, Tochigi, 329-0498, Japan.
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Rokkam D, LaFemina MJ, Lee JW, Matthay MA, Frank JA. Claudin-4 levels are associated with intact alveolar fluid clearance in human lungs. THE AMERICAN JOURNAL OF PATHOLOGY 2011; 179:1081-7. [PMID: 21741940 PMCID: PMC3157178 DOI: 10.1016/j.ajpath.2011.05.017] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/22/2010] [Revised: 05/04/2011] [Accepted: 05/09/2011] [Indexed: 01/11/2023]
Abstract
The removal of edema from the air spaces is a critical function of the alveolar barrier requiring intact tight junctions. Alveolar fluid clearance contributes to graft function after transplantation and is associated with survival in patients with acute lung injury. Claudin-4 concentrations are known to increase during lung injury and the loss of claudin-4 decreases alveolar fluid clearance in mice. This study was therefore undertaken to evaluate whether differences in lung expression of the tight junction protein claudin-4 are associated with alveolar fluid clearance or clinical measures of lung function. Alveolar fluid clearance rates were measured in ex vivo perfused human lungs not used for transplantation and were compared with histological lung injury and clinical measures of lung injury in the donors. Claudin-4 staining demonstrated a positive correlation with alveolar fluid clearance (Spearman rank correlation [r(s)] = 0.71; P < 0.003); however, claudin-4 staining was not strongly associated with histological measures of lung injury. The expression of other tight junction proteins (including ZO-1) was not associated with alveolar fluid clearance or claudin-4 levels. Claudin-4 staining was lower in lungs from donors with greater impairment in respiratory physiology. These data suggest that claudin-4 may promote alveolar fluid clearance and demonstrate that the amount of claudin-4 expressed may provide specific information regarding alveolar epithelial barrier function that strengthens the link between histological changes and physiological impairment.
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Affiliation(s)
- Deepti Rokkam
- San Francisco VA Medical Center, University of California San Francisco, San Francisco, California
- Northern California Institute for Research and Education, University of California San Francisco, San Francisco, California
| | - Michael J. LaFemina
- San Francisco VA Medical Center, University of California San Francisco, San Francisco, California
- Northern California Institute for Research and Education, University of California San Francisco, San Francisco, California
| | - Jae Woo Lee
- Cardiovascular Research Institute, University of California San Francisco, San Francisco, California
| | - Michael A. Matthay
- Cardiovascular Research Institute, University of California San Francisco, San Francisco, California
| | - James A. Frank
- San Francisco VA Medical Center, University of California San Francisco, San Francisco, California
- Northern California Institute for Research and Education, University of California San Francisco, San Francisco, California
- Cardiovascular Research Institute, University of California San Francisco, San Francisco, California
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Rizzolo LJ, Peng S, Luo Y, Xiao W. Integration of tight junctions and claudins with the barrier functions of the retinal pigment epithelium. Prog Retin Eye Res 2011; 30:296-323. [PMID: 21704180 DOI: 10.1016/j.preteyeres.2011.06.002] [Citation(s) in RCA: 113] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2011] [Revised: 06/01/2011] [Accepted: 06/06/2011] [Indexed: 02/02/2023]
Abstract
The retinal pigment epithelium (RPE) forms the outer blood-retinal barrier by regulating the movement of solutes between the fenestrated capillaries of the choroid and the photoreceptor layer of the retina. Blood-tissue barriers use various mechanisms to accomplish their tasks including membrane pumps, transporters, and channels, transcytosis, metabolic alteration of solutes in transit, and passive but selective diffusion. The last category includes tight junctions, which regulate transepithelial diffusion through the spaces between neighboring cells of the monolayer. Tight junctions are extraordinarily complex structures that are dynamically regulated. Claudins are a family of tight junctional proteins that lend tissue specificity and selectivity to tight junctions. This review discusses how the claudins and tight junctions of the RPE differ from other epithelia and how its functions are modulated by the neural retina. Studies of RPE-retinal interactions during development lend insight into this modulation. Notably, the characteristics of RPE junctions, such as claudin composition, vary among species, which suggests the physiology of the outer retina may also vary. Comparative studies of barrier functions among species should deepen our understanding of how homeostasis is maintained in the outer retina. Stem cells provide a way to extend these studies of RPE-retinal interactions to human RPE.
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Affiliation(s)
- Lawrence J Rizzolo
- Department of Surgery and Department of Ophthalmology and Visual Science, Yale University School of Medicine, PO Box 208062, New Haven, CT 06520-8062, USA.
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Zhang K, Tian Y, Yin L, Zhang M, Beck LA, Zhang B, Okunieff P, Zhang L, Vidyasagar S. Fibroblast growth factor-peptide improves barrier function and proliferation in human keratinocytes after radiation. Int J Radiat Oncol Biol Phys 2011; 81:248-54. [PMID: 21489707 DOI: 10.1016/j.ijrobp.2011.02.004] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2010] [Revised: 08/28/2010] [Accepted: 02/03/2011] [Indexed: 11/20/2022]
Abstract
PURPOSE Epidermal keratinocytes, which can be severely damaged after ionizing radiation (IR), are rapid turnover cells that function as a barrier, protecting the host from pathogenic invasion and fluid loss. We tested fibroblast growth factor-peptide (FGF-P), a small peptide derived from the receptor-binding domain of FGF-2, as a potential mitigator of radiation effects via proliferation and the barrier function of keratinocytes. METHODS AND MATERIALS Keratinocytes isolated from neonatal foreskin were grown on transwells. After being exposed to 0, 5, or 10 Gy IR, the cells were treated with a vehicle or FGF-P. The permeability of IR cells was assessed by using transepithelial electrical resistance (TEER) and a paracellular tracer flux of fluorescein isothiocyanate-conjugated bovine serum albumin (FITC-BSA) with Ussing chambers. The cell proliferation was measured with yellow tetrazolium salt (MTT) and tritiated thymidine ([3H]-TdR) assays. The phosphorylation of extracellular signal-regulated kinases (ERK) was measured in an enzyme-linked immunosorbent (ELISA)-like assay, and the proteins related to tight junctions (TJ) and adherens junctions (AJ) were examined with Western blotting. We used a mouse model to assess the ability of FGF-P to promote the healing of skin β burns created with a strontium applicator. RESULTS We found (1) FGF-P reduced the permeability of irradiated keratinocytes, as evidenced by increased TEER and decreased diffusion of FITC-BSA, both associated with the regulation of different proteins and levels of TJ and AJ; and (2) FGF-P enhanced the proliferation of irradiated keratinocytes, as evidenced by increased MTT activity and [3H]-TdR incorporation, which was associated with activation of the ERK pathway; and (3) FGF-P promoted the healing of skin β burns. CONCLUSIONS FGF-P enhances the barrier function, including up-regulation of TJ proteins, increases proliferation of human keratinocytes, and accelerates the healing of skin β burns. FGF-P is a promising mitigator that improves the proliferation and barrier function of keratinocytes after IR.
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Affiliation(s)
- Kunzhong Zhang
- Department of Radiation Oncology, University of Rochester Medical Center, Rochester, New York 14642, USA
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Bornholdt J, Friis S, Godiksen S, Poulsen SS, Santoni-Rugiu E, Bisgaard HC, Lothe IMB, Ikdahl T, Tveit KM, Johnson E, Kure EH, Vogel LK. The level of claudin-7 is reduced as an early event in colorectal carcinogenesis. BMC Cancer 2011; 11:65. [PMID: 21310043 PMCID: PMC3045986 DOI: 10.1186/1471-2407-11-65] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2010] [Accepted: 02/10/2011] [Indexed: 12/11/2022] Open
Abstract
Background Compromised epithelial barriers are found in dysplastic tissue of the gastrointestinal tract. Claudins are transmembrane proteins important for tight junctions. Claudins regulate the paracellular transport and are crucial for maintaining a functional epithelial barrier. Down-regulation of the oncogenic serine protease, matriptase, induces leakiness in epithelial barriers both in vivo and in vitro. We found in an in-silico search tight co-regulation between matriptase and claudin-7 expression. We have previously shown that the matriptase expression level decreases during colorectal carcinogenesis. In the present study we investigated whether claudin-7 expression is likewise decreased during colorectal carcinogenesis, thereby causing or contributing to the compromised epithelial leakiness of dysplastic tissue. Methods The mRNA level of claudin-7 (CLDN7) was determined in samples from 18 healthy individuals, 100 individuals with dysplasia and 121 colorectal cancer patients using quantitative real time RT-PCR. In addition, immunohistochemical stainings were performed on colorectal adenomas and carcinomas, to confirm the mRNA findings. Results A 2.7-fold reduction in the claudin-7 mRNA level was found when comparing the biopsies from healthy individuals with the biopsies of carcinomas (p < 0.001). Reductions in the claudin-7 mRNA levels were also detected in mild/moderate dysplasia (p < 0.001), severe dysplasia (p < 0.01) and carcinomas (p < 0.01), compared to a control sample from the same individual. The decrease at mRNA level was confirmed at the protein level by immunohistochemical stainings. Conclusions Our results show that the claudin-7 mRNA level is decreased already as an early event in colorectal carcinogenesis, probably contributing to the compromised epithelial barrier in adenomas.
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Affiliation(s)
- Jette Bornholdt
- Department of Cellular and Molecular Medicine, Faculty of Health Science, University of Copenhagen, Denmark
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Abstract
Tight junctions (TJs) are the most apical component of the junctional complexes in mammalian epithelial cells and form selective paracellular barriers restricting the passage of solutes and ions across the epithelial sheets. Claudins, a TJ integral membrane protein family, play a critical role in regulating paracellular barrier permeability. In the in vitro cell culture system, transepithelial electrical resistance (TER) measurement and the flux of radioisotope or fluorescent labeled molecules with different sizes have been widely used to determine the TJ barrier function. In the in vivo system, the tracer molecule Sulfo-NHS-Biotin was initially used in Xenopus embryo system and subsequently was successfully applied to a number of animal tissues in situ and in different organisms under the experimental conditions to examine the functional integrity of TJs by several laboratories. In this chapter, we will describe the detailed procedures of applying biotin as a paracellular tracer molecule to different in vivo systems to assay TJ barrier function.
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Amasheh S, Fromm M, Günzel D. Claudins of intestine and nephron - a correlation of molecular tight junction structure and barrier function. Acta Physiol (Oxf) 2011; 201:133-40. [PMID: 20518752 DOI: 10.1111/j.1748-1716.2010.02148.x] [Citation(s) in RCA: 107] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
A prerequisite of epithelial transport is a paracellular barrier function, which seals the tissue against an uncontrolled leak flux. Moreover, selective paracellular permeability has been shown to be crucial for physiological epithelial transport function. Claudins are tetraspan tight junction proteins which play a major role in paracellular ion permeability across epithelia. The multigene family consists of 24 members and several splice variants which show distinct tissue-specific expression profiles. Moreover, in diseases associated with a loss of barrier function such as forms of inflammatory bowel disease, the expression of claudins is altered. Functional characterization of single claudins revealed specific contribution to barrier properties in epithelia. This review gives an overview on the exploration of molecular structure and barrier function along the intestine and nephron, which not only share mechanisms of selective restriction of the paracellular pathway but also exhibit distinct organ-specific characteristics.
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Affiliation(s)
- S Amasheh
- Institute of Clinical Physiology, Charité, Berlin, Germany.
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