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Saha K, Subramenium Ganapathy A, Wang A, Michael Morris N, Suchanec E, Ding W, Yochum G, Koltun W, Nighot M, Ma T, Nighot P. Autophagy Reduces the Degradation and Promotes Membrane Localization of Occludin to Enhance the Intestinal Epithelial Tight Junction Barrier against Paracellular Macromolecule Flux. J Crohns Colitis 2023; 17:433-449. [PMID: 36219473 PMCID: PMC10069622 DOI: 10.1093/ecco-jcc/jjac148] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/11/2022] [Indexed: 01/18/2023]
Abstract
BACKGROUND AND AIMS Functional loss of the gut epithelium's paracellular tight junction [TJ] barrier and defective autophagy are factors potentiating inflammatory bowel disease [IBD]. Previously, we showed the role of autophagy in enhancing the intestinal TJ barrier via pore-forming claudin-2 degradation. How autophagy regulates the TJ barrier-forming proteins remains unknown. Here, we investigated the role of autophagy in the regulation of occludin, a principal TJ component involved in TJ barrier enhancement. RESULTS Autophagy induction using pharmacological activators and nutrient starvation increased total occludin levels in intestinal epithelial cells, mouse colonocytes and human colonoids. Autophagy induction enriched membrane occludin levels and reduced paracellular permeability of macromolecules. Autophagy-mediated TJ barrier enhancement was contingent on the presence of occludin as OCLN-/- nullified its TJ barrier-enhancing effect against macromolecular flux. Autophagy inhibited the constitutive degradation of occludin by preventing its caveolar endocytosis from the membrane and protected against inflammation-induced TJ barrier loss. Autophagy enhanced the phosphorylation of ERK-1/2 and inhibition of these kinases in Caco-2 cells and human colonic mucosa prevented the macromolecular barrier-enhancing effects of autophagy. In vivo, autophagy induction by rapamycin enhanced occludin levels in wild-type mouse intestines and protected against lipopolysaccharide- and tumour necrosis factor-α-induced TJ barrier loss. Disruption of autophagy with acute Atg7 knockout in adult mice decreased intestinal occludin levels, increasing baseline colonic TJ permeability and exacerbating the effect of experimental colitis. CONCLUSION Our data suggest a novel role of autophagy in promoting the intestinal TJ barrier by increasing occludin levels in an ERK1/2 mitogen-activated protein kinase-dependent mechanism.
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Affiliation(s)
- Kushal Saha
- Division of Gastroenterology and Hepatology, Department of Medicine, The Pennsylvania State University College of Medicine, Hershey, PA 17033, USA
| | - Ashwinkumar Subramenium Ganapathy
- Division of Gastroenterology and Hepatology, Department of Medicine, The Pennsylvania State University College of Medicine, Hershey, PA 17033, USA
| | - Alexandra Wang
- Division of Gastroenterology and Hepatology, Department of Medicine, The Pennsylvania State University College of Medicine, Hershey, PA 17033, USA
| | - Nathan Michael Morris
- Division of Gastroenterology and Hepatology, Department of Medicine, The Pennsylvania State University College of Medicine, Hershey, PA 17033, USA
| | - Eric Suchanec
- Division of Gastroenterology and Hepatology, Department of Medicine, The Pennsylvania State University College of Medicine, Hershey, PA 17033, USA
| | - Wei Ding
- Division of Colon and Rectal Surgery, Department of Surgery, The Pennsylvania State University College of Medicine, Hershey, PA 17033, USA
| | - Gregory Yochum
- Division of Colon and Rectal Surgery, Department of Surgery, The Pennsylvania State University College of Medicine, Hershey, PA 17033, USA
| | - Walter Koltun
- Division of Colon and Rectal Surgery, Department of Surgery, The Pennsylvania State University College of Medicine, Hershey, PA 17033, USA
| | - Meghali Nighot
- Division of Gastroenterology and Hepatology, Department of Medicine, The Pennsylvania State University College of Medicine, Hershey, PA 17033, USA
| | - Thomas Ma
- Division of Gastroenterology and Hepatology, Department of Medicine, The Pennsylvania State University College of Medicine, Hershey, PA 17033, USA
| | - Prashant Nighot
- Division of Gastroenterology and Hepatology, Department of Medicine, The Pennsylvania State University College of Medicine, Hershey, PA 17033, USA
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Barabási B, Barna L, Santa-Maria AR, Harazin A, Molnár R, Kincses A, Vigh JP, Dukay B, Sántha M, Tóth ME, Walter FR, Deli MA, Hoyk Z. Role of interleukin-6 and interleukin-10 in morphological and functional changes of the blood-brain barrier in hypertriglyceridemia. Fluids Barriers CNS 2023; 20:15. [PMID: 36882782 PMCID: PMC9990353 DOI: 10.1186/s12987-023-00418-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2022] [Accepted: 02/24/2023] [Indexed: 03/09/2023] Open
Abstract
BACKGROUND Hypertriglyceridemia is closely linked to atherosclerosis related inflammatory processes and blood-brain barrier (BBB) dysfunction. Using apolipoprotein B-100 (APOB-100) transgenic mice, an animal model of chronic hypertriglyceridemia, we analyzed BBB function and morphology in vitro and ex vivo. Our objective was to determine which BBB characteristics are produced mainly by interleukin (IL)-6, an atherosclerosis promoting cytokine, and whether these actions can be antagonized by IL-10, an anti-inflammatory cytokine. METHODS Brain endothelial and glial cell cultures and brain microvessels were isolated from wild type (WT) and APOB-100 transgenic mice and were treated with IL-6, IL-10 and their combination. First, IL-6 and IL-10 production was measured in WT and APOB-100 microvessels using qPCR. Then functional parameters of endothelial cell cultures were analyzed and immunocytochemistry for key BBB proteins was performed. RESULTS IL-6 mRNA levels were higher in brain microvessels than in brain parenchyma of APOB-100 transgenic mice. Transendothelial electric resistance and P-glycoprotein activity were lower, and paracellular permeability was higher in cultured APOB-100 brain endothelial cells. These features were sensitive to both IL-6 and IL-10 treatments. A decreased P-glycoprotein immunostaining was measured in transgenic endothelial cells under control conditions and in WT cells after treating them with IL-6. This effect was antagonized by IL-10. Changes in immunostaining for tight junction proteins were observed after IL-6 exposure, which were in part antagonized by IL-10. In glial cell cultures an increase in aquaporin-4 immunolabeling in the transgenic group and an increase in microglia cell density in WT glia cultures was detected after IL-6 treatment, which was antagonized by IL-10. In isolated brain microvessels a decrease in P-glycoprotein immunolabeled area fraction was measured in APOB-100 microvessels under control conditions and in WT microvessels after every cytokine treatment. ZO-1 immunolabeling showed characteristics similar to that of P-glycoprotein. No change was seen in claudin-5 and occludin immunoreactive area fractions in microvessels. A decrease in aquaporin-4 immunoreactivity was measured in WT microvessels treated by IL-6, which was antagonized by IL-10. CONCLUSION IL-6 produced in microvessels contributes to BBB impairment observed in the APOB-100 mice. We showed that IL-10 partly antagonizes the effects of IL-6 at the BBB.
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Affiliation(s)
- Beáta Barabási
- Institute of Biophysics, Biological Research Centre, Temesvári Krt. 62, Szeged, 6726, Hungary.,Doctoral School of Theoretical Medicine, University of Szeged, Tisza L. Krt. 109, Szeged, 6725, Hungary
| | - Lilla Barna
- Institute of Biophysics, Biological Research Centre, Temesvári Krt. 62, Szeged, 6726, Hungary
| | - Ana Raquel Santa-Maria
- Institute of Biophysics, Biological Research Centre, Temesvári Krt. 62, Szeged, 6726, Hungary.,Wyss Institute for Biologically Inspired Engineering at Harvard University, 3 Blackfan Circle, Boston, MA, 02115, USA
| | - András Harazin
- Institute of Biophysics, Biological Research Centre, Temesvári Krt. 62, Szeged, 6726, Hungary
| | - Réka Molnár
- Institute of Biophysics, Biological Research Centre, Temesvári Krt. 62, Szeged, 6726, Hungary
| | - András Kincses
- Institute of Biophysics, Biological Research Centre, Temesvári Krt. 62, Szeged, 6726, Hungary
| | - Judit P Vigh
- Institute of Biophysics, Biological Research Centre, Temesvári Krt. 62, Szeged, 6726, Hungary
| | - Brigitta Dukay
- Institute of Biochemistry, Biological Research Centre, Temesvári Krt. 62, Szeged, 6726, Hungary
| | - Miklós Sántha
- Institute of Biochemistry, Biological Research Centre, Temesvári Krt. 62, Szeged, 6726, Hungary
| | - Melinda E Tóth
- Institute of Biochemistry, Biological Research Centre, Temesvári Krt. 62, Szeged, 6726, Hungary
| | - Fruzsina R Walter
- Institute of Biophysics, Biological Research Centre, Temesvári Krt. 62, Szeged, 6726, Hungary.
| | - Mária A Deli
- Institute of Biophysics, Biological Research Centre, Temesvári Krt. 62, Szeged, 6726, Hungary.
| | - Zsófia Hoyk
- Institute of Biophysics, Biological Research Centre, Temesvári Krt. 62, Szeged, 6726, Hungary.
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Insights of Endocytosis Signaling in Health and Disease. Int J Mol Sci 2023; 24:ijms24032971. [PMID: 36769293 PMCID: PMC9918140 DOI: 10.3390/ijms24032971] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2022] [Revised: 01/20/2023] [Accepted: 01/31/2023] [Indexed: 02/05/2023] Open
Abstract
Endocytosis in mammalian cells is a fundamental cellular machinery that regulates vital physiological processes, such as the absorption of metabolites, release of neurotransmitters, uptake of hormone cellular defense, and delivery of biomolecules across the plasma membrane. A remarkable characteristic of the endocytic machinery is the sequential assembly of the complex proteins at the plasma membrane, followed by internalization and fusion of various biomolecules to different cellular compartments. In all eukaryotic cells, functional characterization of endocytic pathways is based on dynamics of the protein complex and signal transduction modules. To coordinate the assembly and functions of the numerous parts of the endocytic machinery, the endocytic proteins interact significantly within and between the modules. Clathrin-dependent and -independent endocytosis, caveolar pathway, and receptor mediated endocytosis have been attributed to a greater variety of physiological and pathophysiological roles such as, autophagy, metabolism, cell division, apoptosis, cellular defense, and intestinal permeabilization. Notably, any defect or alteration in the endocytic machinery results in the development of pathological consequences associated with human diseases such as cancer, cardiovascular diseases, neurological diseases, and inflammatory diseases. In this review, an in-depth endeavor has been made to illustrate the process of endocytosis, and associated mechanisms describing pathological manifestation associated with dysregulated endocytosis machinery.
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Wu J, Rowart P, Jouret F, Gassaway BM, Rajendran V, Rinehart J, Caplan MJ. Mechanisms involved in AMPK-mediated deposition of tight junction components to the plasma membrane. Am J Physiol Cell Physiol 2020; 318:C486-C501. [PMID: 31913699 DOI: 10.1152/ajpcell.00422.2019] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
AMP-activated protein kinase (AMPK) activation promotes early stages of epithelial junction assembly. AMPK activation in MDCK renal epithelial cells facilitates localization of the junction-associated proteins aPKCζ and Par3 to the plasma membrane and promotes conversion of Cdc42, a key regulator of epithelial polarization and junction assembly, to its active GTP bound state. Furthermore, Par3 is an important regulator of AMPK-mediated aPKCζ localization. Both aPKCζ and Par3 serve as intermediates in AMPK-mediated junction assembly, with inhibition of aPKCζ activity or Par3 knockdown disrupting AMPK's ability to facilitate zonula occludens (ZO-1) localization. AMPK phosphorylates the adherens junction protein afadin and regulates its interaction with the tight-junction protein zonula occludens-1. Afadin is phosphorylated at two critical sites, S228 (residing within an aPKCζ consensus site) and S1102 (residing within an AMPK consensus site), that are differentially regulated during junction assembly and that exert different effects on the process. Expression of phospho-defective mutants (S228A and S1102A) perturbed ZO-1 localization to the plasma membrane during AMPK-induced junction assembly. Expression of S228A increased the ZO-1/afadin interaction, while S1102A reduced this interaction during extracellular calcium-induced junction assembly. Inhibition of aPKCζ activity also increased the ZO-1/afadin interaction. Taken together, these data suggest that aPKCζ phosphorylation of afadin terminates the ZO-1/afadin interaction and thus permits the later stages of junction assembly.
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Affiliation(s)
- Jingshing Wu
- Department of Cellular and Molecular Physiology, Yale School of Medicine, New Haven, Connecticut
| | - Pascal Rowart
- Groupe Interdisciplinaire de Génoprotéomique Appliquée, Cardiovascular Sciences, University of Liège, Liège, Belgium
| | - Francois Jouret
- Groupe Interdisciplinaire de Génoprotéomique Appliquée, Cardiovascular Sciences, University of Liège, Liège, Belgium
| | - Brandon M Gassaway
- Department of Cellular and Molecular Physiology, Yale School of Medicine, New Haven, Connecticut.,Systems Biology Institute, Yale University, West Haven, Connecticut
| | - Vanathy Rajendran
- Department of Cellular and Molecular Physiology, Yale School of Medicine, New Haven, Connecticut
| | - Jesse Rinehart
- Department of Cellular and Molecular Physiology, Yale School of Medicine, New Haven, Connecticut.,Systems Biology Institute, Yale University, West Haven, Connecticut
| | - Michael J Caplan
- Department of Cellular and Molecular Physiology, Yale School of Medicine, New Haven, Connecticut
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5
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Lavie M, Linna L, Moustafa RI, Belouzard S, Fukasawa M, Dubuisson J. Role of the cytosolic domain of occludin in trafficking and hepatitis C virus infection. Traffic 2019; 20:753-773. [PMID: 31328852 DOI: 10.1111/tra.12680] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2019] [Revised: 07/17/2019] [Accepted: 07/17/2019] [Indexed: 12/12/2022]
Abstract
The role of the tight-junction (TJ) protein occludin (OCLN) in hepatitis C virus (HCV) entry remains elusive. Here, we investigated the OCLN C-terminal cytosolic domain in HCV infection. We expressed a series of C-terminal deletion mutants in Huh-7 cells KO for OCLN and characterized their functionality in HCV infection and trafficking. Deleting the OCLN cytosolic domain led to protein instability and intracellular retention. The first 15 residues (OCLN-C15 mutant) of the cytosolic domain were sufficient for OCLN stability, but led to its accumulation in the trans-Golgi network (TGN) due to a deficient cell surface export after synthesis. In contrast, the OCLN-C18 mutant, containing the first 18 residues of the cytosolic domain, was expressed at the cell surface and could mediate HCV infection. Point mutations in the context of C18 showed that I279 and W281 are crucial residues for cell surface expression of OCLN-C18. However, in the context of full-length OCLN, mutation of these residues only partially affected infection and cell surface localization. Importantly, the characterization of OCLN-C18 in human-polarized hepatocytes revealed a defect in its TJ localization without affecting HCV infection. These data suggest that TJ localization of OCLN is not a prerequisite for HCV infection in polarized hepatocytes.
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Affiliation(s)
- Muriel Lavie
- Universite de Lille, CNRS, Inserm, CHU Lille, Institut Pasteur de Lille, U1019-UMR 8204-CIIL-Center for Infection and Immunity of Lille, Lille, France
| | - Lydia Linna
- Universite de Lille, CNRS, Inserm, CHU Lille, Institut Pasteur de Lille, U1019-UMR 8204-CIIL-Center for Infection and Immunity of Lille, Lille, France
| | - Rehab I Moustafa
- Universite de Lille, CNRS, Inserm, CHU Lille, Institut Pasteur de Lille, U1019-UMR 8204-CIIL-Center for Infection and Immunity of Lille, Lille, France.,Department of Microbial Biotechnology, Genetic Engineering and Biotechnology Division, National Research Center, Cairo, Egypt
| | - Sandrine Belouzard
- Universite de Lille, CNRS, Inserm, CHU Lille, Institut Pasteur de Lille, U1019-UMR 8204-CIIL-Center for Infection and Immunity of Lille, Lille, France
| | - Masayoshi Fukasawa
- Department of Biochemistry & Cell Biology, National Institute of Infectious Diseases, Tokyo, Japan
| | - Jean Dubuisson
- Universite de Lille, CNRS, Inserm, CHU Lille, Institut Pasteur de Lille, U1019-UMR 8204-CIIL-Center for Infection and Immunity of Lille, Lille, France
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6
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Van Itallie CM, Lidman KF, Tietgens AJ, Anderson JM. Newly synthesized claudins but not occludin are added to the basal side of the tight junction. Mol Biol Cell 2019; 30:1406-1424. [PMID: 30943107 PMCID: PMC6724697 DOI: 10.1091/mbc.e19-01-0008] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
A network of claudin strands creates continuous cell–cell contacts to form the intercellular tight junction barrier; a second protein, occludin, is associated along these strands. The physiological barrier remains stable despite protein turnover, which involves removal and replacement of claudins both in the steady state and during junction remodeling. Here we use a pulse–block–pulse labeling protocol with fluorescent ligands to label SNAP/CLIP-tags fused to claudins and occludin to identify their spatial trafficking pathways and kinetics in Madin–Darby canine kidney monolayers. We find that claudins are first delivered to the lateral membrane and, over time, enter the junction strand network from the basal side; this is followed by slow replacement of older claudins in the strands. In contrast, even at early times, newly synthesized occludin is found throughout the network. Taking the results together with our previous documentation of the mechanism for claudin strand assembly in a fibroblast model, we speculate that newly synthesized claudins are added at strand breaks and free ends; these are most common in the basalmost edge of the junction. In contrast, occludin can be added directly within the strand network. We further demonstrate that claudin trafficking and half-life depend on carboxy-terminal sequences and that different claudins compete for tight junction localization.
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Affiliation(s)
- Christina M Van Itallie
- Laboratory of Tight Junction Structure and Function, National Institutes of Health, Bethesda, MD 20892
| | - Karin Fredriksson Lidman
- Laboratory of Tight Junction Structure and Function, National Institutes of Health, Bethesda, MD 20892
| | - Amber Jean Tietgens
- Laboratory of Tight Junction Structure and Function, National Institutes of Health, Bethesda, MD 20892
| | - James Melvin Anderson
- Laboratory of Tight Junction Structure and Function, National Institutes of Health, Bethesda, MD 20892
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Early Porcine Sapovirus Infection Disrupts Tight Junctions and Uses Occludin as a Coreceptor. J Virol 2019; 93:JVI.01773-18. [PMID: 30463963 PMCID: PMC6364031 DOI: 10.1128/jvi.01773-18] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2018] [Accepted: 11/08/2018] [Indexed: 11/20/2022] Open
Abstract
The genus Sapovirus belongs to the family Caliciviridae, and its members are common causative agents of severe acute gastroenteritis in both humans and animals. Some caliciviruses are known to use either terminal sialic acids or histo-blood group antigens as attachment factors and/or cell surface proteins, such as CD300lf, CD300ld, and junctional adhesion molecule 1 of tight junctions (TJs), as receptors. However, the roles of TJs and their proteins in sapovirus entry have not been examined. In this study, we found that porcine sapovirus (PSaV) significantly decreased transepithelial electrical resistance and increased paracellular permeability early in infection of LLC-PK cells, suggesting that PSaV dissociates TJs of cells. This led to the interaction between PSaV particles and occludin, which traveled in a complex into late endosomes via Rab5- and Rab7-dependent trafficking. Inhibition of occludin using small interfering RNA (siRNA), a specific antibody, or a dominant-negative mutant significantly blocked the entry of PSaV. Transient expression of occludin in nonpermissive Chinese hamster ovary (CHO) cells conferred susceptibility to PSaV, but only for a limited time. Although claudin-1, another TJ protein, neither directly interacted nor was internalized with PSaV particles, it facilitated PSaV entry and replication in the LLC-PK cells. We conclude that PSaV particles enter LLC-PK cells by binding to occludin as a coreceptor in PSaV-dissociated TJs. PSaV and occludin then form a complex that moves to late endosomes via Rab5- and Rab7-dependent trafficking. In addition, claudin-1 in the TJs opened by PSaV infection facilitates PSaV entry and infection as an entry factor.IMPORTANCE Sapoviruses (SaVs) cause severe acute gastroenteritis in humans and animals. Although they replicate in intestinal epithelial cells, which are tightly sealed by apical-junctional complexes, such as tight junctions (TJs), the mechanisms by which SaVs hijack TJs and their proteins for successful entry and infection remain largely unknown. Here, we demonstrate that porcine SaVs (PSaVs) induce early dissociation of TJs, allowing them to bind to the TJ protein occludin as a functional coreceptor. PSaVs then travel in a complex with occludin into late endosomes through Rab5- and Rab7-dependent trafficking. Claudin-1, another TJ protein, does not directly interact with PSaV but facilitates the entry of PSaV into cells as an entry factor. This work contributes to our understanding of the entry of SaV and other caliciviruses into cells and may aid in the development of efficient and affordable drugs to treat SaV infections.
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Konno T, Takano K, Kaneko Y, Kakuki T, Nomura K, Yajima R, Kakiuchi A, Kohno T, Himi T, Kojima T. Guanylate binding protein-1-mediated epithelial barrier in human salivary gland duct epithelium. Exp Cell Res 2018; 371:31-41. [PMID: 30044945 DOI: 10.1016/j.yexcr.2018.07.033] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2018] [Revised: 07/19/2018] [Accepted: 07/20/2018] [Indexed: 02/07/2023]
Abstract
Guanylate-binding protein-1 (GBP-1) is an interferon-inducible large GTPase involved in the epithelial barrier at tight junctions. To investigate the role of GBP-1 in the epithelial barrier, primary human salivary gland duct epithelial cells were treated with the the proinflammatory cytokines IFNγ, IL-1β, TNFα and the growth factor TGF-β. Treatment with IFNγ, IL-1β, or TNFα markedly enhanced GBP-1 and the epithelial barrier function, and induced not only CLDN-7 but also the tricellular tight junction molecule lipolysis-stimulated lipoprotein receptor (LSR). Knockdown of GBP-1 by its siRNA induced endocytosis of tight junction molecules, and prevented the increases of CLDN-7 and LSR with the upregulation of the epithelial barrier function induced by treatment with IFNγ or TNFα. Treatment with a PKCα inhibitor induced expression of GBP-1, CLDN-7 and LSR and enhanced the epithelial barrier function. In almost intact salivary gland ducts from patients with IgG4-related disease (IgG4-RD) indicated significant infiltration of IgG-positive plasma cells, expression of GBP-1, CLDN-7 and LSR was increased. These findings indicated that GBP-1 might play a crucial role in barrier function of normal human salivary gland duct epithelium and perform a preventive role in the duct epithelium of IgG4-RD disease.
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Affiliation(s)
- Takumi Konno
- Department of Cell Science, Research Institute for Frontier Medicine, Sapporo Medical University School of Medicine, Sapporo 060-8556, Japan
| | - Kenichi Takano
- Department of Otolaryngology, Sapporo Medical University School of Medicine, Sapporo 060-8556, Japan
| | - Yakuto Kaneko
- Department of Otolaryngology, Sapporo Medical University School of Medicine, Sapporo 060-8556, Japan
| | - Takuya Kakuki
- Department of Otolaryngology, Sapporo Medical University School of Medicine, Sapporo 060-8556, Japan
| | - Kazuaki Nomura
- Department of Otolaryngology, Sapporo Medical University School of Medicine, Sapporo 060-8556, Japan
| | - Ryoto Yajima
- Department of Cell Science, Research Institute for Frontier Medicine, Sapporo Medical University School of Medicine, Sapporo 060-8556, Japan; Department of Otolaryngology, Sapporo Medical University School of Medicine, Sapporo 060-8556, Japan
| | - Akito Kakiuchi
- Department of Cell Science, Research Institute for Frontier Medicine, Sapporo Medical University School of Medicine, Sapporo 060-8556, Japan; Department of Otolaryngology, Sapporo Medical University School of Medicine, Sapporo 060-8556, Japan
| | - Takayuki Kohno
- Department of Cell Science, Research Institute for Frontier Medicine, Sapporo Medical University School of Medicine, Sapporo 060-8556, Japan
| | - Tetsuo Himi
- Department of Otolaryngology, Sapporo Medical University School of Medicine, Sapporo 060-8556, Japan
| | - Takashi Kojima
- Department of Cell Science, Research Institute for Frontier Medicine, Sapporo Medical University School of Medicine, Sapporo 060-8556, Japan.
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Rab25 acts as an oncogene in luminal B breast cancer and is causally associated with Snail driven EMT. Oncotarget 2018; 7:40252-40265. [PMID: 27259233 PMCID: PMC5130006 DOI: 10.18632/oncotarget.9730] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2016] [Accepted: 05/10/2016] [Indexed: 12/13/2022] Open
Abstract
The Rab GTPases regulate vesicular trafficking machinery that transports and delivers a diverse pool of cargo, including growth factor receptors, integrins, nutrient receptors and junction proteins to specific intracellular sites. The trafficking machinery is indeed a major posttranslational modifier and is critical for cellular homeostasis. Deregulation of this stringently controlled system leads to a wide spectrum of disorders including cancer. Herein we demonstrate that Rab25, a key GTPase, mostly decorating the apical recycling endosome, is a dichotomous variable in breast cancer cell lines with higher mRNA and protein expression in Estrogen Receptor positive (ER+ve) lines. Rab25 and its effector, Rab Coupling Protein (RCP) are frequently coamplified and coordinately elevated in ER+ve breast cancers. In contrast, Rab25 levels are decreased in basal-like and almost completely lost in claudin-low tumors. This dichotomy exists despite the presence of the 1q amplicon that hosts Rab25 across breast cancer subtypes and is likely due to differential methylation of the Rab25 promoter. Functionally, elevated levels of Rab25 drive major hallmarks of cancer including indefinite growth and metastasis but in case of luminal B breast cancer only. Importantly, in such ER+ve tumors, coexpression of Rab25 and its effector, RCP is significantly associated with a markedly worsened clinical outcome. Importantly, in claudin-low cell lines, exogenous Rab25 markedly inhibits cell migration. Similarly, during Snail-induced epithelial to mesenchymal transition (EMT) exogenous Rab25 potently reverses Snail-driven invasion. Overall, this study substantiates a striking context dependent role of Rab25 in breast cancer where Rab25 is amplified and enhances aggressiveness in luminal B cancers while in claudin-low tumors, Rab25 is lost indicating possible anti-tumor functions.
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10
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Iqbal M, Doherty N, Page AML, Qazi SNA, Ajmera I, Lund PA, Kypraios T, Scott DJ, Hill PJ, Stekel DJ. Reconstructing promoter activity from Lux bioluminescent reporters. PLoS Comput Biol 2017; 13:e1005731. [PMID: 28922354 PMCID: PMC5619816 DOI: 10.1371/journal.pcbi.1005731] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2017] [Revised: 09/28/2017] [Accepted: 08/19/2017] [Indexed: 11/19/2022] Open
Abstract
The bacterial Lux system is used as a gene expression reporter. It is fast, sensitive and non-destructive, enabling high frequency measurements. Originally developed for bacterial cells, it has also been adapted for eukaryotic cells, and can be used for whole cell biosensors, or in real time with live animals without the need for euthanasia. However, correct interpretation of bioluminescent data is limited: the bioluminescence is different from gene expression because of nonlinear molecular and enzyme dynamics of the Lux system. We have developed a computational approach that, for the first time, allows users of Lux assays to infer gene transcription levels from the light output. This approach is based upon a new mathematical model for Lux activity, that includes the actions of LuxAB, LuxEC and Fre, with improved mechanisms for all reactions, as well as synthesis and turn-over of Lux proteins. The model is calibrated with new experimental data for the LuxAB and Fre reactions from Photorhabdus luminescens—the source of modern Lux reporters—while literature data has been used for LuxEC. Importantly, the data show clear evidence for previously unreported product inhibition for the LuxAB reaction. Model simulations show that predicted bioluminescent profiles can be very different from changes in gene expression, with transient peaks of light output, very similar to light output seen in some experimental data sets. By incorporating the calibrated model into a Bayesian inference scheme, we can reverse engineer promoter activity from the bioluminescence. We show examples where a decrease in bioluminescence would be better interpreted as a switching off of the promoter, or where an increase in bioluminescence would be better interpreted as a longer period of gene expression. This approach could benefit all users of Lux technology. Bioluminescent reporters are used in many areas of biology as fast, sensitive and non-destructive measures of gene expression. They have been developed for bacteria, adapted now for other kinds of organisms, and recently been used for whole cell biosensors, and for real-time live animal models for infection without the need for euthanasia. However, users of Lux technologies rely on the light output being similar to the gene expression they wish to measure. We show that this is not the case. Rather, there is a nonlinear relationship between the two: light output can be misleading and so limits the way that such data can be interpreted. We have developed a new computational method that, for the first time, allows users of Lux reporters to infer accurate gene transcription levels from bioluminescent data. We show examples where a small decrease in light would be better interpreted as promoter being switched off, or where an increase in light would be better interpreted as promoter activity for a longer time.
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Affiliation(s)
- Mudassar Iqbal
- Agricultural and Environmental Sciences, School of Biosciences, University of Nottingham, Sutton Bonington Campus, Loughborough, United Kingdom
| | - Neil Doherty
- Food Sciences, School of Biosciences, University of Nottingham, Sutton Bonington Campus, Loughborough, United Kingdom
| | - Anna M. L. Page
- Food Sciences, School of Biosciences, University of Nottingham, Sutton Bonington Campus, Loughborough, United Kingdom
| | - Saara N. A. Qazi
- Food Sciences, School of Biosciences, University of Nottingham, Sutton Bonington Campus, Loughborough, United Kingdom
| | - Ishan Ajmera
- Plant and Crop Sciences, School of Biosciences, University of Nottingham, Sutton Bonington Campus, Loughborough, United Kingdom
| | - Peter A. Lund
- School of Biosciences, University of Birmingham, Birmingham, United Kingdom
| | - Theodore Kypraios
- School of Mathematical Sciences, University of Nottingham, Nottingham, United Kingdom
| | - David J. Scott
- Food Sciences, School of Biosciences, University of Nottingham, Sutton Bonington Campus, Loughborough, United Kingdom
| | - Philip J. Hill
- Food Sciences, School of Biosciences, University of Nottingham, Sutton Bonington Campus, Loughborough, United Kingdom
| | - Dov J. Stekel
- Agricultural and Environmental Sciences, School of Biosciences, University of Nottingham, Sutton Bonington Campus, Loughborough, United Kingdom
- * E-mail:
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11
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Stamatovic SM, Johnson AM, Sladojevic N, Keep RF, Andjelkovic AV. Endocytosis of tight junction proteins and the regulation of degradation and recycling. Ann N Y Acad Sci 2017; 1397:54-65. [PMID: 28415156 DOI: 10.1111/nyas.13346] [Citation(s) in RCA: 64] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2017] [Revised: 03/08/2017] [Accepted: 03/09/2017] [Indexed: 12/31/2022]
Abstract
Internalization of tight junction (TJ) proteins from the plasma membrane is a pivotal mechanism regulating TJ plasticity and function in both epithelial and endothelial barrier tissues. Once internalized, the TJ proteins enter complex vesicular machinery, where further trafficking is directly dependent on the initiating stimulus and downstream signaling pathways that regulate the sorting and destiny of TJ proteins, as well as on cell and barrier responses. The destiny of internalized TJ proteins is recycling to the plasma membrane or sorting to late endosomes and degradation. This review highlights recent advances in our knowledge of endocytosis and vesicular trafficking of TJ proteins in both epithelial and endothelial cells. A greater understanding of these processes may allow for the development of methods to modulate barrier permeability for drug delivery or prevent barrier dysfunction in disease states.
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Affiliation(s)
| | | | | | - Richard F Keep
- Neurosurgery.,Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, Michigan
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12
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Lechuga S, Ivanov AI. Disruption of the epithelial barrier during intestinal inflammation: Quest for new molecules and mechanisms. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2017; 1864:1183-1194. [PMID: 28322932 DOI: 10.1016/j.bbamcr.2017.03.007] [Citation(s) in RCA: 162] [Impact Index Per Article: 23.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/22/2017] [Revised: 03/13/2017] [Accepted: 03/15/2017] [Indexed: 02/06/2023]
Abstract
The intestinal epithelium forms a key protective barrier that separates internal organs from the harmful environment of the gut lumen. Increased permeability of the gut barrier is a common manifestation of different inflammatory disorders contributing to the severity of disease. Barrier permeability is controlled by epithelial adherens junctions and tight junctions. Junctional assembly and integrity depend on fundamental homeostatic processes such as cell differentiation, rearrangements of the cytoskeleton, and vesicle trafficking. Alterations of intestinal epithelial homeostasis during mucosal inflammation may impair structure and remodeling of apical junctions, resulting in increased permeability of the gut barrier. In this review, we summarize recent advances in our understanding of how altered epithelial homeostasis affects the structure and function of adherens junctions and tight junctions in the inflamed gut. Specifically, we focus on the transcription reprogramming of the cell, alterations in the actin cytoskeleton, and junctional endocytosis and exocytosis. We pay special attention to knockout mouse model studies and discuss the relevance of these mechanisms to human gastrointestinal disorders.
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Affiliation(s)
- Susana Lechuga
- Department of Human and Molecular Genetics, Virginia Commonwealth University, Richmond, VA 23298, USA
| | - Andrei I Ivanov
- Department of Human and Molecular Genetics, Virginia Commonwealth University, Richmond, VA 23298, USA; Virginia Institute of Molecular Medicine, Virginia Commonwealth University, Richmond, VA 23298, USA; Massey Cancer Center, Virginia Commonwealth University, Richmond, VA 23298, USA.
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13
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Nighot PK, Leung L, Ma TY. Chloride channel ClC- 2 enhances intestinal epithelial tight junction barrier function via regulation of caveolin-1 and caveolar trafficking of occludin. Exp Cell Res 2017; 352:113-122. [PMID: 28161538 DOI: 10.1016/j.yexcr.2017.01.024] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2016] [Revised: 01/09/2017] [Accepted: 01/31/2017] [Indexed: 12/16/2022]
Abstract
Previous studies have demonstrated that the chloride channel ClC-2 plays a critical role in intestinal epithelial tight junction (TJ) barrier function via intracellular trafficking of TJ protein occludin. To study the mechanism of ClC-2-mediated TJ barrier function and intracellular trafficking of occludin, we established ClC-2 over-expressing Caco-2 cell line (Caco-2CLCN2) by full length ClC-2 ORF transfection. ClC-2 over-expression (Caco-2CLCN2) significantly enhanced TJ barrier (increased TER by ≥2 times and reduced inulin flux by 50%) compared to control Caco-2pEZ cells. ClC-2 over-expression (Caco-2CLCN2) increased occludin protein level compared to control Caco-2pEZ cells. Surface biotinylation assay revealed reduced steady state endocytosis of occludin in Caco-2CLCN2 cells. Furthermore, ClC-2 over-expression led to reduction in caveolin-1 protein level and diminishment of caveolae assembly. Caveolae disruption increased TJ permeability in control but not ClC-2 over-expressing Caco-2CLCN2 cells. Selective ClC-2 channel blocker GaTx2 caused an increase in caveolin-1 protein level and reduced occludin level. Delivery of cell permeable caveolin-1 scaffolding domain reduced the occludin protein level. Over all, these results suggest that ClC- 2 enhances TJ barrier function in intestinal epithelial cells via regulation of caveolin-1 and caveolae-mediated trafficking of occludin.
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Affiliation(s)
- Prashant K Nighot
- Department of Internal Medicine, University of New Mexico School of Medicine, Albuquerque, NM 87131, USA.
| | - Lana Leung
- Department of Internal Medicine, University of New Mexico School of Medicine, Albuquerque, NM 87131, USA
| | - Thomas Y Ma
- Department of Internal Medicine, University of New Mexico School of Medicine, Albuquerque, NM 87131, USA
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14
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Arya P, Rainey MA, Bhattacharyya S, Mohapatra BC, George M, Kuracha MR, Storck MD, Band V, Govindarajan V, Band H. The endocytic recycling regulatory protein EHD1 Is required for ocular lens development. Dev Biol 2015; 408:41-55. [PMID: 26455409 DOI: 10.1016/j.ydbio.2015.10.005] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2015] [Revised: 09/01/2015] [Accepted: 10/06/2015] [Indexed: 12/24/2022]
Abstract
The C-terminal Eps15 homology domain-containing (EHD) proteins play a key role in endocytic recycling, a fundamental cellular process that ensures the return of endocytosed membrane components and receptors back to the cell surface. To define the in vivo biological functions of EHD1, we have generated Ehd1 knockout mice and previously reported a requirement of EHD1 for spermatogenesis. Here, we show that approximately 56% of the Ehd1-null mice displayed gross ocular abnormalities, including anophthalmia, aphakia, microphthalmia and congenital cataracts. Histological characterization of ocular abnormalities showed pleiotropic defects that include a smaller or absent lens, persistence of lens stalk and hyaloid vasculature, and deformed optic cups. To test whether these profound ocular defects resulted from the loss of EHD1 in the lens or in non-lenticular tissues, we deleted the Ehd1 gene selectively in the presumptive lens ectoderm using Le-Cre. Conditional Ehd1 deletion in the lens resulted in developmental defects that included thin epithelial layers, small lenses and absence of corneal endothelium. Ehd1 deletion in the lens also resulted in reduced lens epithelial proliferation, survival and expression of junctional proteins E-cadherin and ZO-1. Finally, Le-Cre-mediated deletion of Ehd1 in the lens led to defects in corneal endothelial differentiation. Taken together, these data reveal a unique role for EHD1 in early lens development and suggest a previously unknown link between the endocytic recycling pathway and regulation of key developmental processes including proliferation, differentiation and morphogenesis.
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Affiliation(s)
- Priyanka Arya
- Department of Genetics, Cell Biology & Anatomy, College of Medicine, University of Nebraska Medical Center, 985805 Nebraska Medical Center Omaha, NE 68198-5805, USA; Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, 985950 Nebraska Medical Center, NE 68198-5950, USA.
| | - Mark A Rainey
- Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, 985950 Nebraska Medical Center, NE 68198-5950, USA.
| | - Sohinee Bhattacharyya
- Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, 985950 Nebraska Medical Center, NE 68198-5950, USA; Department of Pathology & Microbiology, College of Medicine, University of Nebraska Medical Center, 985900 Nebraska Medical Center Omaha, NE 68198-5900, USA.
| | - Bhopal C Mohapatra
- Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, 985950 Nebraska Medical Center, NE 68198-5950, USA; Department of Biochemistry & Molecular Biology, College of Medicine, University of Nebraska Medical Center, 985870 Nebraska Medical Center Omaha, NE 68198-5870, USA.
| | - Manju George
- Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, 985950 Nebraska Medical Center, NE 68198-5950, USA.
| | - Murali R Kuracha
- Department of Biomedical Sciences, Creighton University, 2500 California Plaza, Omaha, NE 68178, USA.
| | - Matthew D Storck
- Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, 985950 Nebraska Medical Center, NE 68198-5950, USA.
| | - Vimla Band
- Department of Genetics, Cell Biology & Anatomy, College of Medicine, University of Nebraska Medical Center, 985805 Nebraska Medical Center Omaha, NE 68198-5805, USA; Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, 985950 Nebraska Medical Center, NE 68198-5950, USA; Fred & Pamela Buffett Cancer Center, University of Nebraska Medical Center, 985950 Nebraska Medical Center Omaha, NE 68198-5950, USA.
| | - Venkatesh Govindarajan
- Department of Biomedical Sciences, Creighton University, 2500 California Plaza, Omaha, NE 68178, USA.
| | - Hamid Band
- Department of Genetics, Cell Biology & Anatomy, College of Medicine, University of Nebraska Medical Center, 985805 Nebraska Medical Center Omaha, NE 68198-5805, USA; Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, 985950 Nebraska Medical Center, NE 68198-5950, USA; Department of Pathology & Microbiology, College of Medicine, University of Nebraska Medical Center, 985900 Nebraska Medical Center Omaha, NE 68198-5900, USA; Department of Biochemistry & Molecular Biology, College of Medicine, University of Nebraska Medical Center, 985870 Nebraska Medical Center Omaha, NE 68198-5870, USA; Fred & Pamela Buffett Cancer Center, University of Nebraska Medical Center, 985950 Nebraska Medical Center Omaha, NE 68198-5950, USA.
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