1
|
Duszyc K, von Pein JB, Ramnath D, Currin-Ross D, Verma S, Lim F, Sweet MJ, Schroder K, Yap AS. Apical extrusion prevents apoptosis from activating an acute inflammatory program in epithelia. Dev Cell 2023; 58:2235-2248.e6. [PMID: 37647898 DOI: 10.1016/j.devcel.2023.08.009] [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: 02/24/2023] [Revised: 06/20/2023] [Accepted: 08/07/2023] [Indexed: 09/01/2023]
Abstract
Apoptosis is traditionally considered to be an immunologically silent form of cell death. Multiple mechanisms exist to ensure that apoptosis does not stimulate the immune system to cause inflammation or autoimmunity. Against this expectation, we now report that epithelia are programmed to provoke, rather than suppress, inflammation in response to apoptosis. We found that an acute inflammatory response led by neutrophils occurs in zebrafish and cell culture when apoptotic epithelial cells cannot be expelled from the monolayer by apical extrusion. This reflects an intrinsic circuit where ATP released from apoptotic cells stimulates epithelial cells in the immediate vicinity to produce interleukin-8 (IL-8). Apical extrusion therefore prevents inappropriate epithelial inflammation by physically eliminating apoptotic cells before they can activate this pro-inflammatory circuit. This carries the implication that epithelia may be predisposed to inflammation, elicited by sporadic or induced apoptosis, if apical extrusion is compromised.
Collapse
Affiliation(s)
- Kinga Duszyc
- Division of Cell and Developmental Biology, Institute for Molecular Bioscience, The University of Queensland, Brisbane 4072, Australia.
| | - Jessica B von Pein
- Division of Cell and Developmental Biology, Institute for Molecular Bioscience, The University of Queensland, Brisbane 4072, Australia
| | - Divya Ramnath
- Division of Cell and Developmental Biology, Institute for Molecular Bioscience, The University of Queensland, Brisbane 4072, Australia
| | - Denni Currin-Ross
- Division of Cell and Developmental Biology, Institute for Molecular Bioscience, The University of Queensland, Brisbane 4072, Australia
| | - Suzie Verma
- Division of Cell and Developmental Biology, Institute for Molecular Bioscience, The University of Queensland, Brisbane 4072, Australia
| | - Fayth Lim
- Division of Cell and Developmental Biology, Institute for Molecular Bioscience, The University of Queensland, Brisbane 4072, Australia
| | - Matthew J Sweet
- Division of Cell and Developmental Biology, Institute for Molecular Bioscience, The University of Queensland, Brisbane 4072, Australia
| | - Kate Schroder
- Division of Cell and Developmental Biology, Institute for Molecular Bioscience, The University of Queensland, Brisbane 4072, Australia
| | - Alpha S Yap
- Division of Cell and Developmental Biology, Institute for Molecular Bioscience, The University of Queensland, Brisbane 4072, Australia.
| |
Collapse
|
2
|
Park N, Chung JY, Kim MH, Yang WM. Protective effects of inhalation of essential oils from Mentha piperita leaf on tight junctions and inflammation in allergic rhinitis. FRONTIERS IN ALLERGY 2022; 3:1012183. [PMID: 36578435 PMCID: PMC9790934 DOI: 10.3389/falgy.2022.1012183] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2022] [Accepted: 11/04/2022] [Indexed: 12/14/2022] Open
Abstract
Allergic rhinitis is one of the most common diseases, which is caused by IgE-mediated reactions to inhaled allergens. Essential oils from the Mentha piperita leaf (EOM) are known to be effective for various diseases, such as respiratory diseases. However, the effect of inhalation of EOM on tight junctions and inflammation related to allergic rhinitis is not yet known. The purpose of this research was to explain the effects of the inhalation of EOM on tight junctions and inflammation of allergic rhinitis through network pharmacology and an experimental study. For that purpose, a pharmacology network analysis was conducted comprising major components of EOM. Based on the network pharmacology prediction results, we evaluated the effect of EOM on histological changes in mice with ovalbumin and PM10-induced allergic rhinitis. Allergic symptoms, infiltration of inflammatory cells, and regulation of ZO-1 were investigated in mice with allergic rhinitis. Other allergic parameters were also analyzed by reverse transcription polymerase chain reaction and western blot in nasal epithelial cells. In the network analysis, the effects of EOM were closely related to tight junctions and inflammation in allergic rhinitis. Consistent with the results from the network analysis, EOM significantly decreased epithelial thickness, mast cell degranulation, goblet cell secretion, and the infiltration of inflammatory cells in nasal tissue. EOM also regulated the MAPK-NF-κB signaling pathway, which was related to tight junctions in nasal epithelial cells. This research confirmed that inhalation of EOM effectively restores tight junctions and suppresses inflammation in the allergic rhinitis model. These results reveal that EOM has a therapeutic mechanism to treat allergic rhinitis.
Collapse
|
3
|
Berselli A, Benfenati F, Maragliano L, Alberini G. Multiscale modelling of claudin-based assemblies: a magnifying glass for novel structures of biological interfaces. Comput Struct Biotechnol J 2022; 20:5984-6010. [DOI: 10.1016/j.csbj.2022.10.038] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2022] [Revised: 10/24/2022] [Accepted: 10/24/2022] [Indexed: 11/03/2022] Open
|
4
|
Gonschior H, Schmied C, Van der Veen RE, Eichhorst J, Himmerkus N, Piontek J, Günzel D, Bleich M, Furuse M, Haucke V, Lehmann M. Nanoscale segregation of channel and barrier claudins enables paracellular ion flux. Nat Commun 2022; 13:4985. [PMID: 36008380 PMCID: PMC9411157 DOI: 10.1038/s41467-022-32533-4] [Citation(s) in RCA: 23] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2021] [Accepted: 08/04/2022] [Indexed: 11/09/2022] Open
Abstract
The paracellular passage of ions and small molecules across epithelia is controlled by tight junctions, complex meshworks of claudin polymers that form tight seals between neighboring cells. How the nanoscale architecture of tight junction meshworks enables paracellular passage of specific ions or small molecules without compromising barrier function is unknown. Here we combine super-resolution stimulated emission depletion microscopy in live and fixed cells and tissues, multivariate classification of super-resolution images and fluorescence resonance energy transfer to reveal the nanoscale organization of tight junctions formed by mammalian claudins. We show that only a subset of claudins can assemble into characteristic homotypic meshworks, whereas tight junctions formed by multiple claudins display nanoscale organization principles of intermixing, integration, induction, segregation, and exclusion of strand assemblies. Interestingly, channel-forming claudins are spatially segregated from barrier-forming claudins via determinants mainly encoded in their extracellular domains also known to harbor mutations leading to human diseases. Electrophysiological analysis of claudins in epithelial cells suggests that nanoscale segregation of distinct channel-forming claudins enables barrier function combined with specific paracellular ion flux across tight junctions. Meshworks of claudin polymers control the paracellular transport and barrier properties of epithelial tight junctions. Here, the authors show different claudin nanoscale organization principles, finding that claudin segregation enables barrier formation and paracellular ion flux across tight junctions.
Collapse
Affiliation(s)
- Hannes Gonschior
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), 13125, Berlin, Germany
| | - Christopher Schmied
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), 13125, Berlin, Germany
| | | | - Jenny Eichhorst
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), 13125, Berlin, Germany
| | - Nina Himmerkus
- Institute of Physiology, Christian-Albrechts-Universität zu Kiel, 24118, Kiel, Germany
| | - Jörg Piontek
- Clinical Physiology/Nutritional Medicine, Medical Department, Division of Gastroenterology, Infectiology, Rheumatology, Charité - Universitätsmedizin Berlin, 12203, Berlin, Germany
| | - Dorothee Günzel
- Clinical Physiology/Nutritional Medicine, Medical Department, Division of Gastroenterology, Infectiology, Rheumatology, Charité - Universitätsmedizin Berlin, 12203, Berlin, Germany
| | - Markus Bleich
- Institute of Physiology, Christian-Albrechts-Universität zu Kiel, 24118, Kiel, Germany
| | - Mikio Furuse
- Division of Cell Structure, National Institute for Physiological Sciences, Okazaki, Aichi, 444-8787, Japan.,Department of Physiological Sciences, School of Life Science, SOKENDAI (Graduate University for Advanced Studies), Okazaki, Aichi, 444-8585, Japan
| | - Volker Haucke
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), 13125, Berlin, Germany.,Faculty of Biology, Chemistry and Pharmacy, Freie Universität Berlin, 14195, Berlin, Germany
| | - Martin Lehmann
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), 13125, Berlin, Germany.
| |
Collapse
|
5
|
Hashimoto Y, Poirier K, Boddaert N, Hubert L, Aubart M, Kaminska A, Alison M, Desguerre I, Munnich A, Campbell M. Recurrent de novo mutations in CLDN5 induce an anion-selective blood-brain barrier and alternating hemiplegia. Brain 2022; 145:3374-3382. [PMID: 35714222 PMCID: PMC9586545 DOI: 10.1093/brain/awac215] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2022] [Revised: 05/19/2022] [Accepted: 05/26/2022] [Indexed: 11/16/2022] Open
Abstract
Claudin-5 is the most enriched tight junction protein at the blood–brain barrier. Perturbations in its levels of expression have been observed across numerous neurological and neuropsychiatric conditions; however, pathogenic variants in the coding sequence of the gene have never been reported previously. Here, we report the identification of a novel de novo mutation (c.178G>A) in the CLDN5 gene in two unrelated cases of alternating hemiplegia with microcephaly. This mutation (G60R) lies within the first extracellular loop of claudin-5 and based on protein modelling and sequence alignment, we predicted it would modify claudin-5 to become an anion-selective junctional component as opposed to a purely barrier-forming protein. Generation of stably transfected cell lines expressing wild-type or G60R claudin-5 showed that the tight junctions could still form in the presence of the G60R mutation but that the barrier against small molecules was clearly attenuated and displayed higher Cl− ion permeability and lower Na+ permeability. While this study strongly suggests that CLDN5 associated alternating hemiplegia is a channelopathy, it is also the first study to identify the conversion of the blood–brain barrier to an anion-selective channel mediated by a dominant acting variant in CLDN5.
Collapse
Affiliation(s)
- Yosuke Hashimoto
- Smurfit Institute of Genetics, Trinity College Dublin, Dublin 2, Ireland
| | - Karine Poirier
- INSERM UMR1163, Institut Imagine, Université Paris Cité, F-75015, Paris France
| | - Nathalie Boddaert
- Department of pediatric radiology, Hospital Necker Enfants Malades, France
| | - Laurence Hubert
- INSERM UMR1163, Institut Imagine, Université Paris Cité, F-75015, Paris France
| | - Melodie Aubart
- Departments of pediatric neurology and medical genetics, Hospital Necker-Enfants Malades, Université Paris Cité, F-75015, Paris France
| | - Anna Kaminska
- Departments of pediatric neurology and medical genetics, Hospital Necker-Enfants Malades, Université Paris Cité, F-75015, Paris France
| | - Marianne Alison
- Department of pediatric radiology, Hospital Robert Debré, Université Paris Cité, F-75015, Paris France
| | - Isabelle Desguerre
- Departments of pediatric neurology and medical genetics, Hospital Necker-Enfants Malades, Université Paris Cité, F-75015, Paris France
| | - Arnold Munnich
- INSERM UMR1163, Institut Imagine, Université Paris Cité, F-75015, Paris France.,Departments of pediatric neurology and medical genetics, Hospital Necker-Enfants Malades, Université Paris Cité, F-75015, Paris France
| | - Matthew Campbell
- Smurfit Institute of Genetics, Trinity College Dublin, Dublin 2, Ireland
| |
Collapse
|
6
|
Hempel C, Rosenthal R, Fromm A, Krug SM, Fromm M, Günzel D, Piontek J. Tight junction channels claudin-10b and claudin-15: Functional mapping of pore-lining residues. Ann N Y Acad Sci 2022; 1515:129-142. [PMID: 35650657 DOI: 10.1111/nyas.14794] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Although functional and structural models for paracellular channels formed by claudins have been reported, mechanisms regulating charge and size selectivity of these channels are unknown in detail. Here, claudin-15 and claudin-10b cation channels showing high-sequence similarity but differing channel properties were analyzed. Mutants of pore-lining residues were expressed in MDCK-C7 cells. In claudin-15, proposed ion interaction sites (D55 and E64) conserved between both claudins were neutralized. D55N and E64Q substitutions decreased ion permeabilities, and D55N/E64Q had partly additive effects. D55N increased cation dehydration capability and decreased pore diameter. Additionally, residues differing between claudin-15 and -10b close to pore center were analyzed. Claudin-10b-mimicking W63K affected neither assembly nor function of claudin-15 channels. In contrast, in claudin-10b, corresponding (claudin-15b-mimicking) K64W and K64M substitutions disturbed integration into tight junction and slightly altered relative permeabilities for differently sized monovalent cations. Removal of claudin-10b-specific negative charge (D36A substitution) was without effect. The data suggest that a common tetra-aspartate ring (D55/D56) in pore center of claudin-15/-10b channels directly attracts cations, while E64/D65 may be at least partly shielded by W63/K64. Charge at position W63/K64 affects assembly and properties for claudin-10b but not for claudin-15 channels. Our findings add to the mechanistic understanding of the determinants of paracellular cation permeability.
Collapse
Affiliation(s)
- Caroline Hempel
- Clinical Physiology/Nutritional Medicine, Medizinische Klinik für Gastroenterologie, Infektiologie und Rheumatologie, Charité - Universitätsmedizin Berlin, Berlin, Germany
| | - Rita Rosenthal
- Clinical Physiology/Nutritional Medicine, Medizinische Klinik für Gastroenterologie, Infektiologie und Rheumatologie, Charité - Universitätsmedizin Berlin, Berlin, Germany
| | - Anja Fromm
- Clinical Physiology/Nutritional Medicine, Medizinische Klinik für Gastroenterologie, Infektiologie und Rheumatologie, Charité - Universitätsmedizin Berlin, Berlin, Germany
| | - Susanne M Krug
- Clinical Physiology/Nutritional Medicine, Medizinische Klinik für Gastroenterologie, Infektiologie und Rheumatologie, Charité - Universitätsmedizin Berlin, Berlin, Germany
| | - Michael Fromm
- Clinical Physiology/Nutritional Medicine, Medizinische Klinik für Gastroenterologie, Infektiologie und Rheumatologie, Charité - Universitätsmedizin Berlin, Berlin, Germany
| | - Dorothee Günzel
- Clinical Physiology/Nutritional Medicine, Medizinische Klinik für Gastroenterologie, Infektiologie und Rheumatologie, Charité - Universitätsmedizin Berlin, Berlin, Germany
| | - Jörg Piontek
- Clinical Physiology/Nutritional Medicine, Medizinische Klinik für Gastroenterologie, Infektiologie und Rheumatologie, Charité - Universitätsmedizin Berlin, Berlin, Germany
| |
Collapse
|
7
|
Abraham C, Abreu MT, Turner JR. Pattern Recognition Receptor Signaling and Cytokine Networks in Microbial Defenses and Regulation of Intestinal Barriers: Implications for Inflammatory Bowel Disease. Gastroenterology 2022; 162:1602-1616.e6. [PMID: 35149024 PMCID: PMC9112237 DOI: 10.1053/j.gastro.2021.12.288] [Citation(s) in RCA: 42] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/13/2021] [Revised: 11/30/2021] [Accepted: 12/10/2021] [Indexed: 12/23/2022]
Abstract
Inflammatory bowel disease is characterized by defects in epithelial function and dysregulated inflammatory signaling by lamina propria mononuclear cells including macrophages and dendritic cells in response to microbiota. In this review, we focus on the role of pattern recognition receptors in the inflammatory response as well as epithelial barrier regulation. We explore cytokine networks that increase inflammation, regulate paracellular permeability, cause epithelial damage, up-regulate epithelial proliferation, and trigger restitutive processes. We focus on studies using patient samples as well as speculate on pathways that can be targeted to more holistically treat patients with inflammatory bowel disease.
Collapse
Affiliation(s)
- Clara Abraham
- Department of Internal Medicine, Yale University, New Haven, Connecticut.
| | - Maria T. Abreu
- Division of Gastroenterology and Hepatology, Department of Medicine, University of Miami Leonard Miller School of Medicine, Miami, FL
| | - Jerrold R. Turner
- Laboratory of Mucosal Barrier Pathobiology, Department of Pathology, Brigham and Women’s Hospital and Harvard Medical School, Boston, MA
| |
Collapse
|
8
|
Nur Husna SM, Tan HTT, Md Shukri N, Mohd Ashari NS, Wong KK. Nasal Epithelial Barrier Integrity and Tight Junctions Disruption in Allergic Rhinitis: Overview and Pathogenic Insights. Front Immunol 2021; 12:663626. [PMID: 34093555 PMCID: PMC8176953 DOI: 10.3389/fimmu.2021.663626] [Citation(s) in RCA: 52] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2021] [Accepted: 04/22/2021] [Indexed: 12/20/2022] Open
Abstract
Allergic rhinitis (AR) is a common disorder affecting up to 40% of the population worldwide and it usually persists throughout life. Nasal epithelial barrier constitutes the first line of defense against invasion of harmful pathogens or aeroallergens. Cell junctions comprising of tight junctions (TJs), adherens junctions, desmosomes and hemidesmosomes form the nasal epithelial barrier. Impairment of TJ molecules plays causative roles in the pathogenesis of AR. In this review, we describe and discuss the components of TJs and their disruption leading to development of AR, as well as regulation of TJs expression by epigenetic changes, neuro-immune interaction, epithelial-derived cytokines (thymic stromal lymphopoietin, IL-25 and IL-33), T helper 2 (Th2) cytokines (IL-4, IL-5, IL-6 and IL-13) and innate lymphoid cells. These growing evidence support the development of novel therapeutic approaches to restore nasal epithelial TJs expression in AR patients.
Collapse
Affiliation(s)
- Siti Muhamad Nur Husna
- Department of Immunology, School of Medical Sciences Malaysia, Universiti Sains Malaysia, Kubang Kerian, Malaysia
| | - Hern-Tze Tina Tan
- Department of Immunology, School of Medical Sciences Malaysia, Universiti Sains Malaysia, Kubang Kerian, Malaysia
| | - Norasnieda Md Shukri
- Hospital Universiti Sains Malaysia, Kubang Kerian, Malaysia.,Department of Otorhinolaryngology, Head and Neck Surgery, School of Medical Sciences, Universiti Sains Malaysia, Kubang Kerian, Malaysia
| | - Noor Suryani Mohd Ashari
- Department of Immunology, School of Medical Sciences Malaysia, Universiti Sains Malaysia, Kubang Kerian, Malaysia.,Hospital Universiti Sains Malaysia, Kubang Kerian, Malaysia
| | - Kah Keng Wong
- Department of Immunology, School of Medical Sciences Malaysia, Universiti Sains Malaysia, Kubang Kerian, Malaysia.,Hospital Universiti Sains Malaysia, Kubang Kerian, Malaysia
| |
Collapse
|
9
|
Nur Husna SM, Siti Sarah CO, Tan HTT, Md Shukri N, Mohd Ashari NS, Wong KK. Reduced occludin and claudin-7 expression is associated with urban locations and exposure to second-hand smoke in allergic rhinitis patients. Sci Rep 2021; 11:1245. [PMID: 33441633 PMCID: PMC7806883 DOI: 10.1038/s41598-020-79208-y] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2020] [Accepted: 12/04/2020] [Indexed: 01/11/2023] Open
Abstract
The breakdown of nasal epithelial barrier occurs in allergic rhinitis (AR) patients. Impairment of cell junction molecules including tight junctions (TJs) and desmosomes plays causative roles in the pathogenesis of AR. In this study, we investigated the transcript expression levels of TJs including occludin (OCLN), claudin-3 and -7 (CLDN3 and CLDN7), desmoglein 3 (DSG3) and thymic stromal lymphopoietin (TSLP) in AR patients (n = 30) and non-allergic controls (n = 30). Nasal epithelial cells of non-allergic controls and AR patients were collected to examine their mRNA expression levels, and to correlate with clinico-demographical and environmental parameters. We demonstrated that the expression of OCLN (p = 0.009), CLDN3 (p = 0.032) or CLDN7 (p = 0.004) transcript was significantly lower in AR patients compared with non-allergic controls. No significant difference was observed in the expression of DSG3 (p = 0.750) or TSLP (p = 0.991) transcript in AR patients compared with non-allergic controls. A significant association between urban locations and lower OCLN expression (p = 0.010), or exposure to second-hand smoke with lower CLDN7 expression (p = 0.042) was found in AR patients. Interestingly, none of the TJs expression was significantly associated with having pets, frequency of changing bedsheet and housekeeping. These results suggest that defective nasal epithelial barrier in AR patients is attributable to reduced expression of OCLN and CLDN7 associated with urban locations and exposure to second-hand smoke, supporting recent findings that air pollution represents one of the causes of AR.
Collapse
Affiliation(s)
- Siti Muhamad Nur Husna
- Department of Immunology, School of Medical Sciences, Universiti Sains Malaysia, 16150, Kubang Kerian, Kelantan, Malaysia
| | - Che Othman Siti Sarah
- Department of Immunology, School of Medical Sciences, Universiti Sains Malaysia, 16150, Kubang Kerian, Kelantan, Malaysia
| | - Hern-Tze Tina Tan
- Department of Immunology, School of Medical Sciences, Universiti Sains Malaysia, 16150, Kubang Kerian, Kelantan, Malaysia.,Hospital Universiti Sains Malaysia, Jalan Raja Perempuan Zainab II, 16150, Kubang Kerian, Kelantan, Malaysia
| | - Norasnieda Md Shukri
- Hospital Universiti Sains Malaysia, Jalan Raja Perempuan Zainab II, 16150, Kubang Kerian, Kelantan, Malaysia.,Department of Otorhinolaryngology, Head and Neck Surgery, School of Medical Sciences, Universiti Sains Malaysia, 16150, Kubang Kerian, Kelantan, Malaysia
| | - Noor Suryani Mohd Ashari
- Department of Immunology, School of Medical Sciences, Universiti Sains Malaysia, 16150, Kubang Kerian, Kelantan, Malaysia.,Hospital Universiti Sains Malaysia, Jalan Raja Perempuan Zainab II, 16150, Kubang Kerian, Kelantan, Malaysia
| | - Kah Keng Wong
- Department of Immunology, School of Medical Sciences, Universiti Sains Malaysia, 16150, Kubang Kerian, Kelantan, Malaysia. .,Hospital Universiti Sains Malaysia, Jalan Raja Perempuan Zainab II, 16150, Kubang Kerian, Kelantan, Malaysia.
| |
Collapse
|
10
|
Chanez-Paredes SD, Abtahi S, Kuo WT, Turner JR. Differentiating Between Tight Junction-Dependent and Tight Junction-Independent Intestinal Barrier Loss In Vivo. Methods Mol Biol 2021; 2367:249-271. [PMID: 33830456 PMCID: PMC8249353 DOI: 10.1007/7651_2021_389] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The intestinal barrier is an essential component of innate host defense. The single layer of epithelial cells that line the intestine must balance barrier function with both active, transcellular and diffusive, paracellular transport. Tight junctions, which link adjacent cells, form a selectively permeable seal that defines both paracellular transport and barrier properties. Molecules can cross tight junctions by either of two distinct routes, termed pore and the leak pathways, that differ in capacity, charge-selectivity, size-selectivity, and responses to physiological and pathophysiological stimuli. A third intestinal permeability route, the unrestricted pathway, reflects loss of the epithelial barrier, as occurs with mucosal damage, is independent of paracellular and transcellular pathways, and is neither charge- nor size-selective.The most commonly used approach for measuring intestinal permeability in vivo involves gavage of FITC-4 kDa dextran and analysis of the quantity recovered in serum. Unfortunately, this method cannot distinguish between leak and unrestricted pathways, as 4 kDa dextran can cross both. Moreover, 4 kDa dextran is too large to cross the pore pathway and, therefore, provides no information regarding this paracellular flux route. Here we describe a multiplex method that allows simultaneous, independent analysis of each pathway.
Collapse
Affiliation(s)
- Sandra D Chanez-Paredes
- Laboratory of Mucosal Barrier Pathobiology, Department of Pathology, Brigham and Women's Hospital and Harvard Medical School, Boston, MA, USA
| | - Shabnam Abtahi
- Laboratory of Mucosal Barrier Pathobiology, Department of Pathology, Brigham and Women's Hospital and Harvard Medical School, Boston, MA, USA
| | - Wei-Ting Kuo
- Laboratory of Mucosal Barrier Pathobiology, Department of Pathology, Brigham and Women's Hospital and Harvard Medical School, Boston, MA, USA
| | - Jerrold R Turner
- Laboratory of Mucosal Barrier Pathobiology, Department of Pathology, Brigham and Women's Hospital and Harvard Medical School, Boston, MA, USA.
| |
Collapse
|
11
|
Irudayanathan FJ, Nangia S. Paracellular Gatekeeping: What Does It Take for an Ion to Pass Through a Tight Junction Pore? LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2020; 36:6757-6764. [PMID: 32450698 DOI: 10.1021/acs.langmuir.0c00877] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Tight junction pores are physiological gatekeepers of paracellular transport in epithelial tissues. Conventionally, tight junction permeability is determined via in vitro electrophysiology measurements; however, the macroscopic readout does not provide molecular-level understanding into the mechanism of ion permeation. Insight into the factors governing selectivity across the paracellular space is just emerging. In this study, we investigated tight junction pores comprising of claudin-2 and claudin-5 proteins that are structurally similar to subnanometer radii but have measurably different in vitro ion permeabilities. To evaluate the mechanistic differences in ion transport across the pores, we computed the free-energy profiles and relative rate constants for the transport of monovalent (Na+, K+, Cl-) and divalent (Mg2+ and Ca2+) ions through the pores using replica exchange metadynamics. In claudin-2, we demonstrate how a single residue dictates selective permeability of Na+ and K+ ions. In claudin-5, we found no clear preference for anion or cation selectivity; thus, pores formed by claudin-5 are indeed barriers to ion permeation. Mutations to claudin-5 that widen the pore's steric radius did not significantly impact pore selectivity, indicating that electrostatics dominate pore selectivity. The key takeaways from this work are as follows: (a) two pores that are similar in diameter and length can have dissimilar ion conductance, (b) existence of a physical pore does not guarantee ion permeability, and (c) the electrostatic environment created by the pore-lining residues dictates the ion conductivity. These mechanistic understandings of the tight junction pores are critical for the interpretation of tight junction physiology.
Collapse
Affiliation(s)
| | - Shikha Nangia
- Department of Biomedical and Chemical Engineering, Syracuse University, Syracuse, New York 13244, United States
| |
Collapse
|
12
|
Meoli L, Günzel D. Channel functions of claudins in the organization of biological systems. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2020; 1862:183344. [PMID: 32442419 DOI: 10.1016/j.bbamem.2020.183344] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/17/2019] [Revised: 04/27/2020] [Accepted: 05/05/2020] [Indexed: 02/07/2023]
Abstract
Claudins are tight junction proteins mostly appreciated in their function of paracellular barrier-formation. Compared to a virtual absence of any tight junctions, their paracellular sealing role certainly stands out. Yet, it was recognized immediately after the discovery of the first claudins, that some members of the claudin protein family were able to convey size and charge selectivity to the paracellular pathway. Thus, paracellular permeability can be fine-tuned according to the physiological needs of a tissue by inserting these channel-forming claudins into tight junction strands. Precise permeability adjustment is further suggested by the presence of numerous isoforms of channel-forming claudins (claudin-10b-, -15-, -16-like isoforms) in various vertebrate taxa. Moreover, their expression and localization are controlled by multiple transcriptional and posttranslational mechanisms. Consequently, mutation or dysregulation of channel-forming claudins can cause severe diseases. The present review therefore aims at providing an up-to-date report of the current research on these aspects of channel-forming claudins and their possible implications on future developments.
Collapse
Affiliation(s)
- Luca Meoli
- Institute of Clinical Physiology/Nutritional Medicine, Medical Department, Division of Gastroenterology, Infectiology, Rheumatology, Charité - Universitätsmedizin Berlin, 12203 Berlin, Germany
| | - Dorothee Günzel
- Institute of Clinical Physiology/Nutritional Medicine, Medical Department, Division of Gastroenterology, Infectiology, Rheumatology, Charité - Universitätsmedizin Berlin, 12203 Berlin, Germany.
| |
Collapse
|
13
|
Curry JN, Tokuda S, McAnulty P, Yu ASL. Combinatorial expression of claudins in the proximal renal tubule and its functional consequences. Am J Physiol Renal Physiol 2020; 318:F1138-F1146. [PMID: 32174144 DOI: 10.1152/ajprenal.00057.2019] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
The proximal renal tubule (PT) is characterized by a highly conductive paracellular pathway, which contributes to a significant amount of solute and water reabsorption by the kidney. Claudins are tight junction proteins that, in part, determine the paracellular permeability of epithelia. In the present study, we determined the expression pattern of the major PT claudins. We found that claudin-2 and claudin-10 are coexpressed throughout the PT, whereas claudin-3 is coexpressed with claudin-2 predominantly in the proximal straight tubule. Additionally, claudin-2 and claudin-3 are expressed separately within mutually exclusive populations of descending thin limbs. We developed a novel double-inducible Madin-Darby canine kidney I cell model to characterize in vitro the functional effect of coexpression of PT claudins. In keeping with previous studies, we found that claudin-2 alone primarily increased cation (Na+ and Ca2+) permeability, whereas claudin-10a alone increased anion (Cl-) permeability. Coexpression of claudin-2 and claudin-10a together led to a weak physical interaction between the isoforms and the formation of a monolayer with high conductance but neutral charge selectivity. Claudin-3 expression had a negligible effect on all measures of cell permeability, whether expressed alone or together with claudin-2. In cells coexpressing a claudin-2 mutant, S68C, together with claudin-10a, inhibition of cation permeability through the claudin-2 pore with a thiol-reactive pore blocker did not block anion permeation through claudin-10a. We conclude that claudin-2 and claudin-10a form independent paracellular cation- and anion-selective channels that function in parallel.
Collapse
Affiliation(s)
- Joshua N Curry
- Department of Molecular and Integrative Physiology, University of Kansas Medical Center, Kansas City, Kansas.,Jared Grantham Kidney Institute, University of Kansas Medical Center, Kansas City, Kansas
| | - Shinsaku Tokuda
- Division of Nephrology and Hypertension, Department of Internal Medicine, University of Kansas Medical Center, Kansas City, Kansas.,Jared Grantham Kidney Institute, University of Kansas Medical Center, Kansas City, Kansas
| | - Patrick McAnulty
- Division of Nephrology and Hypertension, Department of Internal Medicine, University of Kansas Medical Center, Kansas City, Kansas.,Jared Grantham Kidney Institute, University of Kansas Medical Center, Kansas City, Kansas
| | - Alan S L Yu
- Department of Molecular and Integrative Physiology, University of Kansas Medical Center, Kansas City, Kansas.,Division of Nephrology and Hypertension, Department of Internal Medicine, University of Kansas Medical Center, Kansas City, Kansas.,Jared Grantham Kidney Institute, University of Kansas Medical Center, Kansas City, Kansas
| |
Collapse
|
14
|
Assembly of Tight Junction Strands: Claudin-10b and Claudin-3 Form Homo-Tetrameric Building Blocks that Polymerise in a Channel-Independent Manner. J Mol Biol 2020; 432:2405-2427. [DOI: 10.1016/j.jmb.2020.02.034] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2019] [Revised: 02/12/2020] [Accepted: 02/28/2020] [Indexed: 02/03/2023]
|
15
|
Contributions of Myosin Light Chain Kinase to Regulation of Epithelial Paracellular Permeability and Mucosal Homeostasis. Int J Mol Sci 2020; 21:ijms21030993. [PMID: 32028590 PMCID: PMC7037368 DOI: 10.3390/ijms21030993] [Citation(s) in RCA: 75] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2020] [Revised: 01/30/2020] [Accepted: 01/30/2020] [Indexed: 12/20/2022] Open
Abstract
Intestinal barrier function is required for the maintenance of mucosal homeostasis. Barrier dysfunction is thought to promote progression of both intestinal and systemic diseases. In many cases, this barrier loss reflects increased permeability of the paracellular tight junction as a consequence of myosin light chain kinase (MLCK) activation and myosin II regulatory light chain (MLC) phosphorylation. Although some details about MLCK activation remain to be defined, it is clear that this triggers perijunctional actomyosin ring (PAMR) contraction that leads to molecular reorganization of tight junction structure and composition, including occludin endocytosis. In disease states, this process can be triggered by pro-inflammatory cytokines including tumor necrosis factor-α (TNF), interleukin-1β (IL-1β), and several related molecules. Of these, TNF has been studied in the greatest detail and is known to activate long MLCK transcription, expression, enzymatic activity, and recruitment to the PAMR. Unfortunately, toxicities associated with inhibition of MLCK expression or enzymatic activity make these unsuitable as therapeutic targets. Recent work has, however, identified a small molecule that prevents MLCK1 recruitment to the PAMR without inhibiting enzymatic function. This small molecule, termed Divertin, restores barrier function after TNF-induced barrier loss and prevents disease progression in experimental chronic inflammatory bowel disease.
Collapse
|
16
|
Venugopal S, Anwer S, Szászi K. Claudin-2: Roles beyond Permeability Functions. Int J Mol Sci 2019; 20:ijms20225655. [PMID: 31726679 PMCID: PMC6888627 DOI: 10.3390/ijms20225655] [Citation(s) in RCA: 71] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2019] [Revised: 11/08/2019] [Accepted: 11/09/2019] [Indexed: 12/12/2022] Open
Abstract
Claudin-2 is expressed in the tight junctions of leaky epithelia, where it forms cation-selective and water permeable paracellular channels. Its abundance is under fine control by a complex signaling network that affects both its synthesis and turnover in response to various environmental inputs. Claudin-2 expression is dysregulated in many pathologies including cancer, inflammation, and fibrosis. Claudin-2 has a key role in energy-efficient ion and water transport in the proximal tubules of the kidneys and in the gut. Importantly, strong evidence now also supports a role for this protein as a modulator of vital cellular events relevant to diseases. Signaling pathways that are overactivated in diseases can alter claudin-2 expression, and a good correlation exists between disease stage and claudin-2 abundance. Further, loss- and gain-of-function studies showed that primary changes in claudin-2 expression impact vital cellular processes such as proliferation, migration, and cell fate determination. These effects appear to be mediated by alterations in key signaling pathways. The specific mechanisms linking claudin-2 to these changes remain poorly understood, but adapters binding to the intracellular portion of claudin-2 may play a key role. Thus, dysregulation of claudin-2 may contribute to the generation, maintenance, and/or progression of diseases through both permeability-dependent and -independent mechanisms. The aim of this review is to provide an overview of the properties, regulation, and functions of claudin-2, with a special emphasis on its signal-modulating effects and possible role in diseases.
Collapse
|
17
|
Samanta P, Wang Y, Fuladi S, Zou J, Li Y, Shen L, Weber C, Khalili-Araghi F. Molecular determination of claudin-15 organization and channel selectivity. J Gen Physiol 2018; 150:949-968. [PMID: 29915162 PMCID: PMC6028499 DOI: 10.1085/jgp.201711868] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2017] [Revised: 03/08/2018] [Accepted: 05/04/2018] [Indexed: 12/28/2022] Open
Abstract
Members of the claudin family form tight junctions between adjacent epithelial and endothelial cells. Samanta et al. build an atomic model of claudin-15 using molecular dynamics simulations and conclude that four claudin-15 molecules each contribute an aspartic acid residue to form a selectivity filter. Tight junctions are macromolecular structures that traverse the space between adjacent cells in epithelia and endothelia. Members of the claudin family are known to determine tight junction permeability in a charge- and size-selective manner. Here, we use molecular dynamics simulations to build and refine an atomic model of claudin-15 channels and study its transport properties. Our simulations indicate that claudin-15 forms well-defined channels for ions and molecules and otherwise “seals” the paracellular space through hydrophobic interactions. Ionic currents, calculated from simulation trajectories of wild-type as well as mutant channels, reflect in vitro measurements. The simulations suggest that the selectivity filter is formed by a cage of four aspartic acid residues (D55), contributed by four claudin-15 molecules, which creates a negative electrostatic potential to favor cation flux over anion flux. Charge reversal or charge ablation mutations of D55 significantly reduce cation permeability in silico and in vitro, whereas mutations of other negatively charged pore amino acid residues have a significantly smaller impact on channel permeability and selectivity. The simulations also indicate that water and small ions can pass through the channel, but larger cations, such as tetramethylammonium, do not traverse the pore. Thus, our model provides an atomic view of claudin channels, their transport function, and a potential three-dimensional organization of its selectivity filter.
Collapse
Affiliation(s)
| | - Yitang Wang
- Department of Pathology, The University of Chicago, Chicago, IL.,Department of Surgery, The University of Chicago, Chicago, IL
| | - Shadi Fuladi
- Department of Physics, University of Illinois, Chicago, IL
| | - Jinjing Zou
- Department of Pathology, The University of Chicago, Chicago, IL
| | - Ye Li
- Department of Pathology, The University of Chicago, Chicago, IL
| | - Le Shen
- Department of Pathology, The University of Chicago, Chicago, IL .,Department of Surgery, The University of Chicago, Chicago, IL
| | | | | |
Collapse
|
18
|
Irudayanathan FJ, Wang X, Wang N, Willsey SR, Seddon IA, Nangia S. Self-Assembly Simulations of Classic Claudins—Insights into the Pore Structure, Selectivity, and Higher Order Complexes. J Phys Chem B 2018; 122:7463-7474. [DOI: 10.1021/acs.jpcb.8b03842] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
| | - Xiaoyi Wang
- Department of Biomedical and Chemical Engineering, Syracuse University, Syracuse, New York 13244, United States
| | - Nan Wang
- Department of Biomedical and Chemical Engineering, Syracuse University, Syracuse, New York 13244, United States
| | - Sarah R. Willsey
- Department of Biomedical and Chemical Engineering, Syracuse University, Syracuse, New York 13244, United States
| | - Ian A. Seddon
- Department of Biomedical and Chemical Engineering, Syracuse University, Syracuse, New York 13244, United States
| | - Shikha Nangia
- Department of Biomedical and Chemical Engineering, Syracuse University, Syracuse, New York 13244, United States
| |
Collapse
|
19
|
Buckley A, Turner JR. Cell Biology of Tight Junction Barrier Regulation and Mucosal Disease. Cold Spring Harb Perspect Biol 2018; 10:cshperspect.a029314. [PMID: 28507021 DOI: 10.1101/cshperspect.a029314] [Citation(s) in RCA: 400] [Impact Index Per Article: 66.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Mucosal surfaces are lined by epithelial cells. In the intestine, the epithelium establishes a selectively permeable barrier that supports nutrient absorption and waste secretion while preventing intrusion by luminal materials. Intestinal epithelia therefore play a central role in regulating interactions between the mucosal immune system and luminal contents, which include dietary antigens, a diverse intestinal microbiome, and pathogens. The paracellular space is sealed by the tight junction, which is maintained by a complex network of protein interactions. Tight junction dysfunction has been linked to a variety of local and systemic diseases. Two molecularly and biophysically distinct pathways across the intestinal tight junction are selectively and differentially regulated by inflammatory stimuli. This review discusses the mechanisms underlying these events, their impact on disease, and the potential of using these as paradigms for development of tight junction-targeted therapeutic interventions.
Collapse
Affiliation(s)
- Aaron Buckley
- Departments of Pathology and Medicine (Gastroenterology), Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts 02115
| | - Jerrold R Turner
- Departments of Pathology and Medicine (Gastroenterology), Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts 02115
| |
Collapse
|
20
|
Rosenthal R, Günzel D, Theune D, Czichos C, Schulzke JD, Fromm M. Water channels and barriers formed by claudins. Ann N Y Acad Sci 2017. [PMID: 28636801 DOI: 10.1111/nyas.13383] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Physiological studies in leaky epithelia, like kidney proximal tubules and the small intestine, have documented water transport via both transcellular and paracellular pathways. The discovery of aquaporin water channels provided a molecular basis for transcellular water movement. In contrast, the contribution, or even existence, of a specific paracellular water pathway has been disputed for a long time, until the cation channel-forming tight junction protein claudin-2 was shown to also permit the paracellular passage of water through its pore. In proximal kidney tubules, claudin-2-based water transport contributes 23-30% of the total water transport. Other paracellular ion channels (claudin-10a, -10b, and -17) proved to be impermeable to water, although their pore size would be sufficient for water molecules to pass. Studies of barrier-forming claudins, like claudin-1 and claudin-3, which tighten the paracellular pathway against ions and larger solutes, indicate that changes in the expression of these sealing claudins do not influence transepithelial water permeability. The present genetic, molecular, computational, and physiological studies are just now beginning to probe the mechanisms and regulation of paracellular permeation.
Collapse
Affiliation(s)
- Rita Rosenthal
- Institute of Clinical Physiology, Department of Gastroenterology, Rheumatology and Infectious Diseases, Charité - Universitätsmedizin Berlin, Berlin, Germany
| | - Dorothee Günzel
- Institute of Clinical Physiology, Department of Gastroenterology, Rheumatology and Infectious Diseases, Charité - Universitätsmedizin Berlin, Berlin, Germany
| | - Dian Theune
- Institute of Clinical Physiology, Department of Gastroenterology, Rheumatology and Infectious Diseases, Charité - Universitätsmedizin Berlin, Berlin, Germany
| | - Carolina Czichos
- Institute of Clinical Physiology, Department of Gastroenterology, Rheumatology and Infectious Diseases, Charité - Universitätsmedizin Berlin, Berlin, Germany
| | - Jörg-Dieter Schulzke
- Institute of Clinical Physiology, Department of Gastroenterology, Rheumatology and Infectious Diseases, Charité - Universitätsmedizin Berlin, Berlin, Germany
| | - Michael Fromm
- Institute of Clinical Physiology, Department of Gastroenterology, Rheumatology and Infectious Diseases, Charité - Universitätsmedizin Berlin, Berlin, Germany
| |
Collapse
|
21
|
Abstract
PURPOSE OF REVIEW Paracellular transport across the tight junction is a general mechanism for transepithelial transport of solutes in epithelia, including the renal tubule. However, why paracellular transport evolved, given the existence of a highly versatile system for transcellular transport, is unknown. RECENT FINDINGS Recent studies have identified the paracellular channel, claudin-2, that is responsible for paracellular reabsorption of sodium in the proximal renal tubule. Knockout of claudin-2 in mice impairs proximal sodium and fluid reabsorption but is compensated by upregulation of sodium reabsorption in the loop of Henle. This occurs at the expense of increased renal oxygen consumption, hypoxia of the outer medulla and increased susceptibility to ischemic kidney injury. SUMMARY Paracellular transport can be viewed as a mechanism to exploit the potential energy in existing electrochemical gradients to drive passive transepithelial transport without consuming additional energy. In this way, it enhances the efficiency of energy utilization by transporting epithelia.
Collapse
|
22
|
Irudayanathan FJ, Wang N, Wang X, Nangia S. Architecture of the paracellular channels formed by claudins of the blood–brain barrier tight junctions. Ann N Y Acad Sci 2017; 1405:131-146. [DOI: 10.1111/nyas.13378] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2017] [Revised: 04/12/2017] [Accepted: 04/14/2017] [Indexed: 01/31/2023]
Affiliation(s)
| | - Nan Wang
- Department of Biomedical and Chemical Engineering Syracuse University Syracuse New York
| | - Xiaoyi Wang
- Department of Biomedical and Chemical Engineering Syracuse University Syracuse New York
| | - Shikha Nangia
- Department of Biomedical and Chemical Engineering Syracuse University Syracuse New York
| |
Collapse
|
23
|
Suzuki H, Tani K, Fujiyoshi Y. Crystal structures of claudins: insights into their intermolecular interactions. Ann N Y Acad Sci 2017; 1397:25-34. [PMID: 28605828 DOI: 10.1111/nyas.13371] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2017] [Revised: 04/06/2017] [Accepted: 04/10/2017] [Indexed: 12/14/2022]
Abstract
Claudins are four-transmembrane proteins that constitute the backbone of tight junction strands via self-polymerization in the apicolateral membranes of epithelial cells. Together with their cell-cell adhesion function, claudin proteins form the paracellular barrier and/or channels through epithelial cell sheets whose permeability is primarily dependent on the claudin subtype. Recently determined crystal structures of several claudins revealed the unique claudin fold of four transmembrane helices in a left-handed helical bundle with an extracellular β-sheet domain. Here, we focus on the structural basis of the intermolecular interactions between claudin molecules and between the Clostridium perfringens enterotoxin and its receptor claudins.
Collapse
Affiliation(s)
- Hiroshi Suzuki
- Cellular and Structural Physiology Institute (CeSPI), Nagoya University, Chikusa, Nagoya, Japan
| | - Kazutoshi Tani
- Cellular and Structural Physiology Institute (CeSPI), Nagoya University, Chikusa, Nagoya, Japan
| | - Yoshinori Fujiyoshi
- Cellular and Structural Physiology Institute (CeSPI), Nagoya University, Chikusa, Nagoya, Japan.,Department of Basic Medical Science, Graduate School of Pharmaceutical Science, Nagoya University, Chikusa, Nagoya, Japan
| |
Collapse
|
24
|
Tight junctions of the proximal tubule and their channel proteins. Pflugers Arch 2017; 469:877-887. [DOI: 10.1007/s00424-017-2001-3] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2017] [Revised: 05/13/2017] [Accepted: 05/16/2017] [Indexed: 12/20/2022]
|
25
|
Contributions of intestinal epithelial barriers to health and disease. Exp Cell Res 2017; 358:71-77. [PMID: 28342899 DOI: 10.1016/j.yexcr.2017.03.036] [Citation(s) in RCA: 52] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2017] [Accepted: 03/16/2017] [Indexed: 12/15/2022]
Abstract
A core function of epithelia is to form barriers that separate tissue compartments within complex organisms. These barriers also separate the internal milieu from the external environment and are, therefore, an essential component of host defense. However, in many cases, a perfect barrier would be improbable with life itself. Examples include the air spaces within the lungs, the renal tubules, and the intestines. Here, we focus on the mechanisms by which barriers are assembled, maintained, and regulated in the context of health and disease. Because of its unique challenges and extensive study, we focus on the gastrointestinal tract as an organ-specific example of the essential contributions of the paracellular barrier to life.
Collapse
|
26
|
Rosenthal R, Günzel D, Krug SM, Schulzke JD, Fromm M, Yu ASL. Claudin-2-mediated cation and water transport share a common pore. Acta Physiol (Oxf) 2017; 219:521-536. [PMID: 27359349 DOI: 10.1111/apha.12742] [Citation(s) in RCA: 86] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2015] [Revised: 11/19/2015] [Accepted: 06/28/2016] [Indexed: 12/19/2022]
Abstract
AIM Claudin-2 is a tight junction protein typically located in 'leaky' epithelia exhibiting large paracellular permeabilities like small intestine and proximal kidney tubule. Former studies revealed that claudin-2 forms paracellular channels for small cations like sodium and potassium and also paracellular channels for water. This study analyses whether the diffusive transport of sodium and water occurs through a common pore of the claudin-2 channel. METHODS Wild-type claudin-2 and different claudin-2 mutants were expressed in MDCK I kidney tubule cells using an inducible system. Ion and water permeability and the effect of blocking reagents on both were investigated on different clones of the mutants. RESULTS Neutralization of a negatively charged cation interaction site in the pore with the mutation, D65N, decreased both sodium permeability and water permeability. Claudin-2 mutants (I66C and S68C) with substitution of the pore-lining amino acids with cysteine were used to test the effect of steric blocking of the claudin-2 pore by thiol-reactive reagents. Addition of thiol-reactive reagents to these mutants simultaneously decreased conductance and water permeability. Remarkably, all experimental perturbations caused parallel changes in ion conductance and water permeability, disproving different or independent passage pathways. CONCLUSION Our results indicate that claudin-2-mediated cation and water transport are frictionally coupled and share a common pore. This pore is lined and determined in permeability by amino acid residues of the first extracellular loop of claudin-2.
Collapse
Affiliation(s)
- R. Rosenthal
- Department of Gastroenterology, Infectious Diseases and Rheumatology; Institute of Clinical Physiology; Campus Benjamin Franklin; Charité - Universitätsmedizin Berlin; Berlin Germany
| | - D. Günzel
- Department of Gastroenterology, Infectious Diseases and Rheumatology; Institute of Clinical Physiology; Campus Benjamin Franklin; Charité - Universitätsmedizin Berlin; Berlin Germany
| | - S. M. Krug
- Department of Gastroenterology, Infectious Diseases and Rheumatology; Institute of Clinical Physiology; Campus Benjamin Franklin; Charité - Universitätsmedizin Berlin; Berlin Germany
| | - J.-D. Schulzke
- Department of Gastroenterology, Infectious Diseases and Rheumatology; Institute of Clinical Physiology; Campus Benjamin Franklin; Charité - Universitätsmedizin Berlin; Berlin Germany
| | - M. Fromm
- Department of Gastroenterology, Infectious Diseases and Rheumatology; Institute of Clinical Physiology; Campus Benjamin Franklin; Charité - Universitätsmedizin Berlin; Berlin Germany
| | - A. S. L. Yu
- Division of Nephrology and Hypertension, and the Kidney Institute; University of Kansas Medical Center; Kansas City KS USA
| |
Collapse
|
27
|
Abstract
Mucosal barriers separate self from non-self and are essential for life. These barriers, which are the first line of defense against external pathogens, are formed by epithelial cells and the substances they secrete. Rather than an absolute barrier, epithelia at mucosal surfaces must allow selective paracellular flux that discriminates between solutes and water while preventing the passage of bacteria and toxins. In vertebrates, tight junctions seal the paracellular space; flux across the tight junction can occur through two distinct routes that differ in selectivity, capacity, molecular composition and regulation. Dysregulation of either pathway can accompany disease. A third, tight-junction-independent route that reflects epithelial damage can also contribute to barrier loss during disease. In this Cell Science at a Glance article and accompanying poster, we present current knowledge on the molecular components and pathways that establish this selectively permeable barrier and the interactions that lead to barrier dysfunction during disease.
Collapse
Affiliation(s)
- Marion M France
- Department of Medicine (Gastroenterology, Hepatology, and Endoscopy), Brigham and Women's Hospital and Harvard Medical School, 20 Shattuck St, TH1428, Boston, MA 02115, USA
| | - Jerrold R Turner
- Department of Medicine (Gastroenterology, Hepatology, and Endoscopy), Brigham and Women's Hospital and Harvard Medical School, 20 Shattuck St, TH1428, Boston, MA 02115, USA
- Department of Pathology, Brigham and Women's Hospital and Harvard Medical School, 20 Shattuck St, TH1428, Boston, MA 02115, USA
| |
Collapse
|
28
|
Abstract
A fundamental function of the intestinal epithelium is to act as a barrier that limits interactions between luminal contents such as the intestinal microbiota, the underlying immune system and the remainder of the body, while supporting vectorial transport of nutrients, water and waste products. Epithelial barrier function requires a contiguous layer of cells as well as the junctions that seal the paracellular space between epithelial cells. Compromised intestinal barrier function has been associated with a number of disease states, both intestinal and systemic. Unfortunately, most current clinical data are correlative, making it difficult to separate cause from effect in interpreting the importance of barrier loss. Some data from experimental animal models suggest that compromised epithelial integrity might have a pathogenic role in specific gastrointestinal diseases, but no FDA-approved agents that target the epithelial barrier are presently available. To develop such therapies, a deeper understanding of both disease pathogenesis and mechanisms of barrier regulation must be reached. Here, we review and discuss mechanisms of intestinal barrier loss and the role of intestinal epithelial barrier function in pathogenesis of both intestinal and systemic diseases. We conclude with a discussion of potential strategies to restore the epithelial barrier.
Collapse
Affiliation(s)
- Matthew A Odenwald
- Department of Pathology, The University of Chicago, 5841 South Maryland, Chicago, Illinois 60637, USA
| | - Jerrold R Turner
- Department of Pathology, The University of Chicago, 5841 South Maryland, Chicago, Illinois 60637, USA
- Departments of Pathology and Medicine (Gastroenterology), Brigham and Women's Hospital and Harvard Medical School, 20 Shattuck Street, Thorn 1428, Boston, Massachusetts 02115, USA
| |
Collapse
|
29
|
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.
Collapse
Affiliation(s)
- Shigeaki Muto
- Division of Nephrology, Department of Internal Medicine, Jichi Medical University, Shimotsuke, Tochigi, Japan
| |
Collapse
|
30
|
Wu RL, Vazquez-Roque M, Carlson P, Burton D, Grover M, Camilleri M, Turner JR. Gluten-induced symptoms in diarrhea-predominant irritable bowel syndrome are associated with increased myosin light chain kinase activity and claudin-15 expression. J Transl Med 2017; 97:14-23. [PMID: 27869798 PMCID: PMC5215009 DOI: 10.1038/labinvest.2016.118] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2016] [Revised: 09/26/2016] [Accepted: 10/01/2016] [Indexed: 02/08/2023] Open
Abstract
The mechanisms underlying diarrhea-predominant irritable bowel syndrome (IBS-D) are poorly understood, but increased intestinal permeability is thought to contribute to symptoms. A recent clinical trial of gluten-free diet (GFD) demonstrated symptomatic improvement, relative to gluten-containing diet (GCD), which was associated with reduced intestinal permeability in non-celiac disease IBS-D patients. The aim of this study was to characterize intestinal epithelial tight junction composition in IBS-D before and after dietary gluten challenge. Biopsies from 27 IBS-D patients (13 GFD and 14 GCD) were examined by H&E staining and semiquantitative immunohistochemistry for phosphorylated myosin II regulatory light chain (MLC), MLC kinase, claudin-2, claudin-8 and claudin-15. Diet-induced changes were assessed and correlated with urinary mannitol excretion (after oral administration). In the small intestine, epithelial MLC phosphorylation was increased or decreased by GCD or GFD, respectively, and this correlated with increased intestinal permeability (P<0.03). Colonocyte expression of the paracellular Na+ channel claudin-15 was also markedly augmented following GCD challenge (P<0.05). Conversely, colonic claudin-2 expression correlated with reduced intestinal permeability (P<0.03). Claudin-8 expression was not affected by dietary challenge. These data show that alterations in MLC phosphorylation and claudin-15 and claudin-2 expression are associated with gluten-induced symptomatology and intestinal permeability changes in IBS-D. The results provide new insight into IBS-D mechanisms and can explain permeability responses to gluten challenge in these patients.
Collapse
Affiliation(s)
- Richard Licheng Wu
- Department of Pathology, The University of Chicago, Chicago, Illinois,Department of Pathology and Laboratory Medicine, Jackson Memorial Hospital, University of Miami, Miami, Florida
| | - Maria Vazquez-Roque
- Division of Gastroenterology & Hepatology, Clinical Enteric Neuroscience Translational and Epidemiological Research, College of Medicine, Mayo Clinic, Rochester, Minnesota
| | - Paula Carlson
- Division of Gastroenterology & Hepatology, Clinical Enteric Neuroscience Translational and Epidemiological Research, College of Medicine, Mayo Clinic, Rochester, Minnesota
| | - Duane Burton
- Division of Gastroenterology & Hepatology, Clinical Enteric Neuroscience Translational and Epidemiological Research, College of Medicine, Mayo Clinic, Rochester, Minnesota
| | - Madhusudan Grover
- Division of Gastroenterology & Hepatology, Clinical Enteric Neuroscience Translational and Epidemiological Research, College of Medicine, Mayo Clinic, Rochester, Minnesota
| | - Michael Camilleri
- Division of Gastroenterology & Hepatology, Clinical Enteric Neuroscience Translational and Epidemiological Research, College of Medicine, Mayo Clinic, Rochester, Minnesota
| | - Jerrold R. Turner
- Department of Pathology, The University of Chicago, Chicago, Illinois,Division of Gastroenterology & Hepatology, Clinical Enteric Neuroscience Translational and Epidemiological Research, College of Medicine, Mayo Clinic, Rochester, Minnesota
| |
Collapse
|
31
|
Laghaei R, Yu ASL, Coalson RD. Water and ion permeability of a claudin model: A computational study. Proteins 2016; 84:305-15. [PMID: 26650625 DOI: 10.1002/prot.24969] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2015] [Revised: 11/02/2015] [Accepted: 11/29/2015] [Indexed: 01/27/2023]
Abstract
At present, the three-dimensional structure of the multimeric paracellular claudin pore is unknown. Using extant biophysical data concerning the size of the pore and permeation of water and cations through it, two three-dimensional models of the pore are constructed in silico. Molecular Dynamics (MD) calculations are then performed to compute water and sodium ion permeation fluxes under the influence of applied hydrostatic pressure. Comparison to experiment is made, under the assumption that the hydrostatic pressure applied in the simulations is equivalent to osmotic pressure induced in experimental measurements of water/ion permeability. One model, in which pore-lining charged is distributed evenly over a selectivity filter section 10-16 Å in length, is found to be generally consistent with experimental data concerning the dependence of water and ion permeation on channel pore diameter, pore length, and the sign and magnitude of pore lining charge. The molecular coupling mechanism between water and ion flow under conditions where hydrostatic pressure is applied is computationally elucidated.
Collapse
Affiliation(s)
- Rozita Laghaei
- Department of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania, 15260
| | - Alan S L Yu
- Kidney Institute, University of Kansas Medical Center, Kansas City, Kansas
| | - Rob D Coalson
- Department of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania, 15260
| |
Collapse
|
32
|
Irudayanathan FJ, Trasatti JP, Karande P, Nangia S. Molecular Architecture of the Blood Brain Barrier Tight Junction Proteins–A Synergistic Computational and In Vitro Approach. J Phys Chem B 2015; 120:77-88. [DOI: 10.1021/acs.jpcb.5b09977] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Affiliation(s)
| | - John P. Trasatti
- Department
of Chemistry and Chemical Biology, Rensselaer Polytechnic Institute, Troy, New York 12180, United States
| | - Pankaj Karande
- Department
of Chemical and Biological Engineering, Rensselaer Polytechnic Institute, Troy, New York 12180, United States
| | - Shikha Nangia
- Department
of Biomedical and Chemical Engineering, Syracuse University, Syracuse New York 13244, United States
| |
Collapse
|
33
|
Weber CR, Liang GH, Wang Y, Das S, Shen L, Yu ASL, Nelson DJ, Turner JR. Claudin-2-dependent paracellular channels are dynamically gated. eLife 2015; 4:e09906. [PMID: 26568313 PMCID: PMC4755754 DOI: 10.7554/elife.09906] [Citation(s) in RCA: 81] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2015] [Accepted: 11/12/2015] [Indexed: 12/28/2022] Open
Abstract
Intercellular tight junctions form selectively permeable barriers that seal the paracellular space. Trans-tight junction flux has been measured across large epithelial surfaces, but conductance across individual channels has never been measured. We report a novel trans-tight junction patch clamp technique that detects flux across individual claudin-2 channels within the tight junction of cultured canine renal tubule or human intestinal epithelial monolayers. In both cells, claudin-2 channels display conductances of ~90 pS. The channels are gated, strictly dependent on claudin-2 expression, and display size- and charge-selectivity typical of claudin-2. Kinetic analyses indicate one open and two distinct closed states. Conductance is symmetrical and reversible, characteristic of a passive, paracellular process, and blocked by reduced temperature or site-directed mutagenesis and chemical derivatization of the claudin-2 pore. We conclude that claudin-2 forms gated paracellular channels and speculate that modulation of tight junction channel gating kinetics may be an unappreciated mechanism of barrier regulation. DOI:http://dx.doi.org/10.7554/eLife.09906.001 Epithelial cells form layers that line the inner surface of the gut, lungs and other organs. They act as barriers to control the movement of water, ions and small molecules between internal compartments within the body and the external environment. Some substances are transported across these barriers by passing through individual epithelial cells, but others pass through the spaces between adjacent cells. These spaces are sealed by tight junctions. If the tight junctions do not work properly, it can cause problems with regulating the movement of molecules across epithelial-lined surfaces. This in turn can contribute to diseases in humans, including inflammatory bowel disease and chronic kidney disease. Proteins called claudins form channels that only allow certain molecules to pass through tight junctions. One member of this family, called claudin-2, allows sodium ions and other small positively charged ions to cross between adjacent cells. However, it is not clear how these channels work, largely due to the absence of appropriate tools to study this process. Here, Weber et al. adapted a technique called patch clamping to study the behavior of individual claudin-2 channels in the tight junctions between mammalian epithelial cells. Weber et al. found that claudin-2 allows positively charged ions to move across a tight junction in short bursts rather than in a steady stream as had been suggested by previous work. These bursts typically begin and end in less than a millisecond. Further experiments revealed that claudin-2 channels have several states; in one state the channel is fully open, in another the channel is firmly closed, and in the third state the channel is temporarily closed but primed to open. Further experiments show that mutations in the gene that encodes claudin-2 or drugs that inhibit claudin-2's function alter the open and closed behaviors of these trans-tight junction channels. The technique developed by Weber et al. will enable researchers to understand how channel proteins at tight junctions assemble and operate. Such studies may lead to the development of drugs that can alter the activity of these channels to treat particular diseases. DOI:http://dx.doi.org/10.7554/eLife.09906.002
Collapse
Affiliation(s)
| | - Guo Hua Liang
- Department of Pathology, The University of Chicago, Chicago, United States
| | - Yitang Wang
- Department of Pathology, The University of Chicago, Chicago, United States
| | - Sudipto Das
- Department of Pathology, The University of Chicago, Chicago, United States
| | - Le Shen
- Department of Pathology, The University of Chicago, Chicago, United States
| | - Alan S L Yu
- Division of Nephrology and Hypertension, University of Kansas Medical Center, Kansas City, United States.,Kidney Institute, University of Kansas Medical Center, Kansas City, United States
| | - Deborah J Nelson
- Department of Pharmacological and Physiological Sciences, The University of Chicago, Chicago, United States
| | - Jerrold R Turner
- Department of Pathology, The University of Chicago, Chicago, United States.,Departments of Pathology and Medicine (GI), Brigham and Women's Hospital and Harvard Medical School, Boston, United States
| |
Collapse
|
34
|
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]
|
35
|
Conceptual barriers to understanding physical barriers. Semin Cell Dev Biol 2015; 42:13-21. [PMID: 26003050 DOI: 10.1016/j.semcdb.2015.04.008] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2015] [Accepted: 04/26/2015] [Indexed: 01/18/2023]
Abstract
The members of the large family of claudin proteins regulate ion and water flux across the tight junction. Many claudins, e.g. claudins 2 and 15, accomplish this by forming size- and charge-selective paracellular channels. Claudins also appear to be essential for genesis of tight junction strands and recruitment of other proteins to these sites. What is less clear is whether claudins form the paracellular seal. While this seal is defective when claudins are disrupted, some results, including ultrastructural and biochemical data, suggest that lipid structures are an important component of tight junction strands and may be responsible for the paracellular seal. This review highlights current understanding of claudin contributions to barrier function and tight junction structure and suggests a model by which claudins and other tight junction proteins can drive assembly and stabilization of a lipid-based strand structure.
Collapse
|
36
|
Luettig J, Rosenthal R, Barmeyer C, Schulzke JD. Claudin-2 as a mediator of leaky gut barrier during intestinal inflammation. Tissue Barriers 2015; 3:e977176. [PMID: 25838982 DOI: 10.4161/21688370.2014.977176] [Citation(s) in RCA: 183] [Impact Index Per Article: 20.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2014] [Accepted: 10/10/2014] [Indexed: 02/07/2023] Open
Abstract
The epithelial tight junction determines the paracellular water and ion movement in the intestine and also prevents uptake of larger molecules, including antigens, in an uncontrolled manner. Claudin-2, one of the 27 mammalian claudins regulating that barrier function, forms a paracellular channel for small cations and water. It is typically expressed in leaky epithelia like proximal nephron and small intestine and provides a major pathway for the paracellular transport of sodium, potassium, and fluid. In intestinal inflammation (Crohn's disease, ulcerative colitis), immune-mediated diseases (celiac disease), and infections (HIV enteropathy), claudin-2 is upregulated in small and large intestine and contributes to diarrhea via a leak flux mechanism. In parallel to that upregulation, other epithelial and tight junctional features are altered and the luminal uptake of antigenic macromolecules is enhanced, for which claudin-2 may be partially responsible through induction of tight junction strand discontinuities.
Collapse
Key Words
- AP, activator protein
- CARD15, caspase recruitment domain-containing protein 15
- Crohn's disease
- DSS, dextran sodium sulfate
- ECL, extracellular loop
- ERK, extracellular-regulated kinase
- HIV
- HIV, human immunodeficiency virus
- HNF, hepatocyte nuclear factor
- IBD, inflammatory bowel disease
- IFN, interferon
- IFNγ
- IL, interleukin
- JAM, junctional adhesion molecule
- JNK, c-jun N-terminal kinase
- LPS, lipopolysaccharides
- MAPK, mitogen-activated protein kinase
- MDCK, Madine Darby canine kidney
- MLC, myosin light chain
- NFκB, nuclear factor kappa B
- NOD2, nucleotide-binding oligomerization domain-containing protein 2
- PI3K, phosphatidyl-inositol-3-kinase
- ROCK, Rho kinase
- Rho, ras homolog
- STAT, signal transducers and activators of transcription
- TEER, transepithelial electrical resistance
- TJ, tight junction
- TNBS, 2,4,6-trinitrobenzene sulfonic acid
- TNF, tumor necrosis factor
- TNFα
- Tat, trans-activator of transcription
- Vpr, viral protein r; ZO, zonula occludens
- celiac disease
- claudin-2
- gp, glycoprotein
- inflammatory bowel disease
- tight junction
- ulcerative colitis
Collapse
Affiliation(s)
- J Luettig
- Institute of Clinical Physiology; Department of Gastroenterology; Charité ; Berlin, Germany
| | - R Rosenthal
- Institute of Clinical Physiology; Department of Gastroenterology; Charité ; Berlin, Germany
| | - C Barmeyer
- Institute of Clinical Physiology; Department of Gastroenterology; Charité ; Berlin, Germany
| | - J D Schulzke
- Institute of Clinical Physiology; Department of Gastroenterology; Charité ; Berlin, Germany
| |
Collapse
|
37
|
Brune K, Frank J, Schwingshackl A, Finigan J, Sidhaye VK. Pulmonary epithelial barrier function: some new players and mechanisms. Am J Physiol Lung Cell Mol Physiol 2015; 308:L731-45. [PMID: 25637609 DOI: 10.1152/ajplung.00309.2014] [Citation(s) in RCA: 89] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2014] [Accepted: 01/27/2015] [Indexed: 12/20/2022] Open
Abstract
The pulmonary epithelium serves as a barrier to prevent access of the inspired luminal contents to the subepithelium. In addition, the epithelium dictates the initial responses of the lung to both infectious and noninfectious stimuli. One mechanism by which the epithelium does this is by coordinating transport of diffusible molecules across the epithelial barrier, both through the cell and between cells. In this review, we will discuss a few emerging paradigms of permeability changes through altered ion transport and paracellular regulation by which the epithelium gates its response to potentially detrimental luminal stimuli. This review is a summary of talks presented during a symposium in Experimental Biology geared toward novel and less recognized methods of epithelial barrier regulation. First, we will discuss mechanisms of dynamic regulation of cell-cell contacts in the context of repetitive exposure to inhaled infectious and noninfectious insults. In the second section, we will briefly discuss mechanisms of transcellular ion homeostasis specifically focused on the role of claudins and paracellular ion-channel regulation in chronic barrier dysfunction. In the next section, we will address transcellular ion transport and highlight the role of Trek-1 in epithelial responses to lung injury. In the final section, we will outline the role of epithelial growth receptor in barrier regulation in baseline, acute lung injury, and airway disease. We will then end with a summary of mechanisms of epithelial control as well as discuss emerging paradigms of the epithelium role in shifting between a structural element that maintains tight cell-cell adhesion to a cell that initiates and participates in immune responses.
Collapse
Affiliation(s)
- Kieran Brune
- Division of Pulmonary and Critical Care Medicine, Johns Hopkins University, Baltimore, Maryland
| | - James Frank
- The Division of Pulmonary and Critical Care Medicine, University of California, San Francisco, San Francisco VA Medical Center, and NCIRE/Veterans Health Research Institute, San Francisco, California
| | - Andreas Schwingshackl
- Department of Pediatrics, University of Tennessee Health Science Center, Memphis, Tennessee
| | - James Finigan
- Division of Oncology, Cancer Center, National Jewish Health, Denver, Colorado
| | - Venkataramana K Sidhaye
- Division of Pulmonary and Critical Care Medicine, Johns Hopkins University, Baltimore, Maryland;
| |
Collapse
|