1
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Schaller ML, Sykes ML, Mecano J, Solanki S, Huang W, Rebernick RJ, Beydoun S, Wang E, Bugarin-Lapuz A, Shah YM, Leiser SF. Fmo5 plays a sex-specific role in goblet cell maturation and mucus barrier formation. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.04.05.588360. [PMID: 38645243 PMCID: PMC11030302 DOI: 10.1101/2024.04.05.588360] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/23/2024]
Abstract
The intestine plays a key role in metabolism, nutrient and water absorption, and provides both physical and immunological defense against dietary and luminal antigens. The protective mucus lining in the intestine is a critical component of intestinal barrier function that when compromised, can lead to dysfunctional intestinal barriers that are a defining characteristic of inflammatory bowel disease (IBD), among other intestinal diseases. Here, we define a new role for the flavin-containing monooxygenase family of enzymes in maintaining a healthy intestinal epithelium. In nematodes, we find that Cefmo-2 is necessary and sufficient for proper intestinal barrier function, intestinal actin expression, and is induced by intestinal damage. In mice, we utilize an intestine-specific, inducible knockout model of the prevalent gut Fmo (Fmo5) and find striking phenotypes within two weeks of knockout. These phenotypes include sex-dependent changes in colon epithelial histology, goblet cell localization and maturation factors, and mucus barrier formation. Each of these changes are significantly more severe in female mice, plausibly mirroring differences observed in some types of IBD in humans. Looking further at these phenotypes, we find increased protein folding stress in Fmo5 knockout animals and successfully rescue the severe female phenotype with addition of a chemical ER chaperone. Together, our results identify a new role for Fmo5 in the mammalian intestine and support a key role for Fmo5 in maintenance of ER/protein homeostasis and proper mucus barrier formation.
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2
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Le Goupil S, Laprade H, Aubry M, Chevet E. Exploring the IRE1 interactome: From canonical signaling functions to unexpected roles. J Biol Chem 2024; 300:107169. [PMID: 38494075 PMCID: PMC11007444 DOI: 10.1016/j.jbc.2024.107169] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2023] [Revised: 03/04/2024] [Accepted: 03/08/2024] [Indexed: 03/19/2024] Open
Abstract
The unfolded protein response is a mechanism aiming at restoring endoplasmic reticulum (ER) homeostasis and is likely involved in other adaptive pathways. The unfolded protein response is transduced by three proteins acting as sensors and triggering downstream signaling pathways. Among them, inositol-requiring enzyme 1 alpha (IRE1α) (referred to as IRE1 hereafter), an endoplasmic reticulum-resident type I transmembrane protein, exerts its function through both kinase and endoribonuclease activities, resulting in both X-box binding protein 1 mRNA splicing and RNA degradation (regulated ire1 dependent decay). An increasing number of studies have reported protein-protein interactions as regulators of these signaling mechanisms, and additionally, driving other noncanonical functions. In this review, we deliver evolutive and structural insights on IRE1 and further describe how this protein interaction network (interactome) regulates IRE1 signaling abilities or mediates other cellular processes through catalytic-independent mechanisms. Moreover, we focus on newly discovered targets of IRE1 kinase activity and discuss potentially novel IRE1 functions based on the nature of the interactome, thereby identifying new fields to explore regarding this protein's biological roles.
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Affiliation(s)
- Simon Le Goupil
- INSERM U1242, University of Rennes, Rennes, France; Centre de Lutte contre le cancer Eugène Marquis, Rennes, France.
| | - Hadrien Laprade
- INSERM U1242, University of Rennes, Rennes, France; Centre de Lutte contre le cancer Eugène Marquis, Rennes, France
| | - Marc Aubry
- INSERM U1242, University of Rennes, Rennes, France; Centre de Lutte contre le cancer Eugène Marquis, Rennes, France
| | - Eric Chevet
- INSERM U1242, University of Rennes, Rennes, France; Centre de Lutte contre le cancer Eugène Marquis, Rennes, France
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3
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Neidhardt L, Cloots E, Friemel N, Weiss CAM, Harding HP, McLaughlin SH, Janssens S, Ron D. The IRE1β-mediated unfolded protein response is repressed by the chaperone AGR2 in mucin producing cells. EMBO J 2024; 43:719-753. [PMID: 38177498 PMCID: PMC10907699 DOI: 10.1038/s44318-023-00014-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2023] [Revised: 11/07/2023] [Accepted: 11/15/2023] [Indexed: 01/06/2024] Open
Abstract
Effector mechanisms of the unfolded protein response (UPR) in the endoplasmic reticulum (ER) are well-characterised, but how ER proteostasis is sensed is less well understood. Here, we exploited the beta isoform of the UPR transducer IRE1, that is specific to mucin-producing cells in order to gauge the relative regulatory roles of activating ligands and repressing chaperones of the specialised ER of goblet cells. Replacement of the stress-sensing luminal domain of endogenous IRE1α in CHO cells (normally expressing neither mucin nor IRE1β) with the luminal domain of IRE1β deregulated basal IRE1 activity. The mucin-specific chaperone AGR2 repressed IRE1 activity in cells expressing the domain-swapped IRE1β/α chimera, but had no effect on IRE1α. Introduction of the goblet cell-specific client MUC2 reversed AGR2-mediated repression of the IRE1β/α chimera. In vitro, AGR2 actively de-stabilised the IRE1β luminal domain dimer and formed a reversible complex with the inactive monomer. These features of the IRE1β-AGR2 couple suggest that active repression of IRE1β by a specialised mucin chaperone subordinates IRE1 activity to a proteostatic challenge unique to goblet cells, a challenge that is otherwise poorly recognised by the pervasive UPR transducers.
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Affiliation(s)
- Lisa Neidhardt
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge, CB2 0XY, UK.
| | - Eva Cloots
- Laboratory for ER stress and Inflammation, VIB Center for Inflammation Research, Technologiepark-Zwijnaarde 71, 9052, Ghent, Belgium
- Department of Pediatrics and Internal Medicine, Faculty of Medicine and Health Sciences, Ghent University, Technologiepark-Zwijnaarde 71, 9052, Ghent, Belgium
| | - Natalie Friemel
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge, CB2 0XY, UK
| | - Caroline A M Weiss
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge, CB2 0XY, UK
| | - Heather P Harding
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge, CB2 0XY, UK
| | - Stephen H McLaughlin
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge, CB2 0QH, UK
| | - Sophie Janssens
- Laboratory for ER stress and Inflammation, VIB Center for Inflammation Research, Technologiepark-Zwijnaarde 71, 9052, Ghent, Belgium
- Department of Pediatrics and Internal Medicine, Faculty of Medicine and Health Sciences, Ghent University, Technologiepark-Zwijnaarde 71, 9052, Ghent, Belgium
| | - David Ron
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge, CB2 0XY, UK.
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4
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Ottens F, Efstathiou S, Hoppe T. Cutting through the stress: RNA decay pathways at the endoplasmic reticulum. Trends Cell Biol 2023:S0962-8924(23)00236-2. [PMID: 38008608 DOI: 10.1016/j.tcb.2023.11.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2023] [Revised: 11/07/2023] [Accepted: 11/08/2023] [Indexed: 11/28/2023]
Abstract
The endoplasmic reticulum (ER) is central to the processing of luminal, transmembrane, and secretory proteins, and maintaining a functional ER is essential for organismal physiology and health. Increased protein-folding load on the ER causes ER stress, which activates quality control mechanisms to restore ER function and protein homeostasis. Beyond protein quality control, mRNA decay pathways have emerged as potent ER fidelity regulators, but their mechanistic roles in ER quality control and their interrelationships remain incompletely understood. Herein, we review ER-associated RNA decay pathways - including regulated inositol-requiring enzyme 1α (IRE1α)-dependent mRNA decay (RIDD), nonsense-mediated mRNA decay (NMD), and Argonaute-dependent RNA silencing - in ER homeostasis, and highlight the intricate coordination of ER-targeted RNA and protein decay mechanisms and their association with antiviral defense.
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Affiliation(s)
- Franziska Ottens
- Institute for Genetics, University of Cologne, Cologne, Germany; Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Cologne, Germany
| | - Sotirios Efstathiou
- Institute for Genetics, University of Cologne, Cologne, Germany; Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Cologne, Germany
| | - Thorsten Hoppe
- Institute for Genetics, University of Cologne, Cologne, Germany; Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Cologne, Germany; Center for Molecular Medicine Cologne (CMMC), Faculty of Medicine and University Hospital of Cologne, Cologne, Germany.
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5
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Bartoszewska S, Sławski J, Collawn JF, Bartoszewski R. Dual RNase activity of IRE1 as a target for anticancer therapies. J Cell Commun Signal 2023:10.1007/s12079-023-00784-5. [PMID: 37721642 DOI: 10.1007/s12079-023-00784-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2023] [Accepted: 08/31/2023] [Indexed: 09/19/2023] Open
Abstract
The unfolded protein response (UPR) is a cellular mechanism that protects cells during stress conditions in which there is an accumulation of misfolded proteins in the endoplasmic reticulum (ER). UPR activates three signaling pathways that function to alleviate stress conditions and promote cellular homeostasis and cell survival. During unmitigated stress conditions, however, UPR activation signaling changes to promote cell death through apoptosis. Interestingly, cancer cells take advantage of this pathway to facilitate survival and avoid apoptosis even during prolonged cell stress conditions. Here, we discuss different signaling pathways associated with UPR and focus specifically on one of the ER signaling pathways activated during UPR, inositol-requiring enzyme 1α (IRE1). The rationale is that the IRE1 pathway is associated with cell fate decisions and recognized as a promising target for cancer therapeutics. Here we discuss IRE1 inhibitors and how they might prove to be an effective cancer therapeutic.
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Affiliation(s)
- Sylwia Bartoszewska
- Department of Inorganic Chemistry, Medical University of Gdansk, Gdansk, Poland
| | - Jakub Sławski
- Department of Biophysics, Faculty of Biotechnology, University of Wrocław, F. Joliot-Curie 14a Street, 50-383, Wrocław, Poland
| | - James F Collawn
- Department of Cell, Developmental, and Integrative Biology, University of Alabama at Birmingham, Birmingham, AL, 35233, USA
| | - Rafał Bartoszewski
- Department of Biophysics, Faculty of Biotechnology, University of Wrocław, F. Joliot-Curie 14a Street, 50-383, Wrocław, Poland.
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6
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Ajoolabady A, Kaplowitz N, Lebeaupin C, Kroemer G, Kaufman RJ, Malhi H, Ren J. Endoplasmic reticulum stress in liver diseases. Hepatology 2023; 77:619-639. [PMID: 35524448 PMCID: PMC9637239 DOI: 10.1002/hep.32562] [Citation(s) in RCA: 61] [Impact Index Per Article: 61.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/02/2021] [Revised: 03/05/2022] [Accepted: 03/08/2022] [Indexed: 02/02/2023]
Abstract
The endoplasmic reticulum (ER) is an intracellular organelle that fosters the correct folding of linear polypeptides and proteins, a process tightly governed by the ER-resident enzymes and chaperones. Failure to shape the proper 3-dimensional architecture of proteins culminates in the accumulation of misfolded or unfolded proteins within the ER, disturbs ER homeostasis, and leads to canonically defined ER stress. Recent studies have elucidated that cellular perturbations, such as lipotoxicity, can also lead to ER stress. In response to ER stress, the unfolded protein response (UPR) is activated to reestablish ER homeostasis ("adaptive UPR"), or, conversely, to provoke cell death when ER stress is overwhelmed and sustained ("maladaptive UPR"). It is well documented that ER stress contributes to the onset and progression of multiple hepatic pathologies including NAFLD, alcohol-associated liver disease, viral hepatitis, liver ischemia, drug toxicity, and liver cancers. Here, we review key studies dealing with the emerging role of ER stress and the UPR in the pathophysiology of liver diseases from cellular, murine, and human models. Specifically, we will summarize current available knowledge on pharmacological and non-pharmacological interventions that may be used to target maladaptive UPR for the treatment of nonmalignant liver diseases.
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Affiliation(s)
- Amir Ajoolabady
- Department of Cardiology, Shanghai Institute for Cardiovascular Diseases, Zhongshan Hospital Fudan University, Shanghai, China
| | - Neil Kaplowitz
- Division of Gastrointestinal and Liver Disease, Department of Medicine, Keck School of Medicine, University of Southern California, Los Angeles, CA 90033, USA
- USC Research Center for Liver Disease, Keck School of Medicine, University of Southern California, Los Angeles, CA 90033, USA
| | - Cynthia Lebeaupin
- Degenerative Diseases Program, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA 92037, USA
| | - Guido Kroemer
- Centre de Recherche des Cordeliers, Equipe labellisée par la Ligue contre le cancer, Université de Paris, Sorbonne Université, Inserm U1138, Institut Universitaire de France, Paris, France
- Metabolomics and Cell Biology Platforms, Institut Gustave Roussy, Villejuif, France
- Pôle de Biologie, Hôpital Européen Georges Pompidou, AP-HP, Paris, France
| | - Randal J. Kaufman
- Degenerative Diseases Program, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA 92037, USA
| | - Harmeet Malhi
- Division of Gastroenterology and Hepatology, Mayo Clinic, Rochester, MN 55905, USA
| | - Jun Ren
- Department of Cardiology, Shanghai Institute for Cardiovascular Diseases, Zhongshan Hospital Fudan University, Shanghai, China
- Department of Laboratory Medicine and Pathology, University of Washington, Seattle, WA 98195, USA
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7
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Mechanism and Role of Endoplasmic Reticulum Stress in Osteosarcoma. Biomolecules 2022; 12:biom12121882. [PMID: 36551309 PMCID: PMC9775044 DOI: 10.3390/biom12121882] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2022] [Revised: 12/11/2022] [Accepted: 12/13/2022] [Indexed: 12/23/2022] Open
Abstract
Osteosarcoma is the most common malignant bone tumor, often occurring in children and adolescents. The etiology of most patients is unclear, and the current conventional treatment methods are chemotherapy, radiotherapy, and surgical resection. However, the sensitivity of osteosarcoma to radiotherapy and chemotherapy is low, and the prognosis is poor. The development of new and useful treatment strategies for improving patient survival is an urgent need. It has been found that endoplasmic reticulum (ER) stress (ERS) affects tumor angiogenesis, invasion, etc. By summarizing the literature related to osteosarcoma and ERS, we found that the unfolded protein response (UPR) pathway activated by ERS has a regulatory role in osteosarcoma proliferation, apoptosis, and chemoresistance. In osteosarcoma, the UPR pathway plays an important role by crosstalk with autophagy, oxidative stress, and other pathways. Overall, this article focuses on the relationship between ERS and osteosarcoma and reviews the potential of drugs or gene targets associated with ERS for the treatment of osteosarcoma.
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8
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Chen L, Bi M, Zhang Z, Du X, Chen X, Jiao Q, Jiang H. The functions of IRE1α in neurodegenerative diseases: Beyond ER stress. Ageing Res Rev 2022; 82:101774. [PMID: 36332756 DOI: 10.1016/j.arr.2022.101774] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2022] [Revised: 10/19/2022] [Accepted: 10/29/2022] [Indexed: 11/05/2022]
Abstract
Inositol-requiring enzyme 1 α (IRE1α) is a type I transmembrane protein that resides in the endoplasmic reticulum (ER). IRE1α, which is the primary sensor of ER stress, has been proven to maintain intracellular protein homeostasis by activating X-box binding protein 1 (XBP1). Further studies have revealed novel physiological functions of the IRE1α, such as its roles in mRNA and protein degradation, inflammation, immunity, cell proliferation and cell death. Therefore, the function of IRE1α is not limited to its role in ER stress; IRE1α is also important for regulating other processes related to cellular physiology. Furthermore, IRE1α plays a key role in neurodegenerative diseases that are caused by the phosphorylation of Tau protein, the accumulation of α-synuclein (α-syn) and the toxic effects of mutant Huntingtin (mHtt). Therefore, targeting IRE1α is a valuable approach for treating neurodegenerative diseases and regulating cell functions. This review discusses the role of IRE1α in different cellular processes, and emphasizes the importance of IRE1α in neurodegenerative diseases.
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Affiliation(s)
- Ling Chen
- Department of Physiology, Shandong Provincial Key Laboratory of Pathogenesis and Prevention of Neurological Disorders and State Key Disciplines: Physiology, School of Basic Medicine, Qingdao University, Qingdao, China
| | - Mingxia Bi
- Department of Physiology, Shandong Provincial Key Laboratory of Pathogenesis and Prevention of Neurological Disorders and State Key Disciplines: Physiology, School of Basic Medicine, Qingdao University, Qingdao, China
| | - Zhen Zhang
- Department of Physiology, Shandong Provincial Key Laboratory of Pathogenesis and Prevention of Neurological Disorders and State Key Disciplines: Physiology, School of Basic Medicine, Qingdao University, Qingdao, China
| | - Xixun Du
- Department of Physiology, Shandong Provincial Key Laboratory of Pathogenesis and Prevention of Neurological Disorders and State Key Disciplines: Physiology, School of Basic Medicine, Qingdao University, Qingdao, China
| | - Xi Chen
- Department of Physiology, Shandong Provincial Key Laboratory of Pathogenesis and Prevention of Neurological Disorders and State Key Disciplines: Physiology, School of Basic Medicine, Qingdao University, Qingdao, China
| | - Qian Jiao
- Department of Physiology, Shandong Provincial Key Laboratory of Pathogenesis and Prevention of Neurological Disorders and State Key Disciplines: Physiology, School of Basic Medicine, Qingdao University, Qingdao, China.
| | - Hong Jiang
- Department of Physiology, Shandong Provincial Key Laboratory of Pathogenesis and Prevention of Neurological Disorders and State Key Disciplines: Physiology, School of Basic Medicine, Qingdao University, Qingdao, China; University of Health and Rehabilitation Sciences, Qingdao, China.
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9
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Grey MJ, De Luca H, Ward DV, Kreulen IA, Bugda Gwilt K, Foley SE, Thiagarajah JR, McCormick BA, Turner JR, Lencer WI. The epithelial-specific ER stress sensor ERN2/IRE1β enables host-microbiota crosstalk to affect colon goblet cell development. J Clin Invest 2022; 132:e153519. [PMID: 35727638 PMCID: PMC9435652 DOI: 10.1172/jci153519] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2021] [Accepted: 06/16/2022] [Indexed: 11/17/2022] Open
Abstract
Epithelial cells lining mucosal surfaces of the gastrointestinal and respiratory tracts uniquely express ERN2/IRE1β, a paralogue of the most evolutionarily conserved endoplasmic reticulum stress sensor, ERN1/IRE1α. How ERN2 functions at the host-environment interface and why a second paralogue evolved remain incompletely understood. Using conventionally raised and germ-free Ern2-/- mice, we found that ERN2 was required for microbiota-induced goblet cell maturation and mucus barrier assembly in the colon. This occurred only after colonization of the alimentary tract with normal gut microflora, which induced Ern2 expression. ERN2 acted by splicing Xbp1 mRNA to expand ER function and prevent ER stress in goblet cells. Although ERN1 can also splice Xbp1 mRNA, it did not act redundantly to ERN2 in this context. By regulating assembly of the colon mucus layer, ERN2 further shaped the composition of the gut microbiota. Mice lacking Ern2 had a dysbiotic microbial community that failed to induce goblet cell development and increased susceptibility to colitis when transferred into germ-free WT mice. These results show that ERN2 evolved at mucosal surfaces to mediate crosstalk between gut microbes and the colonic epithelium required for normal homeostasis and host defense.
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Affiliation(s)
- Michael J. Grey
- Division of Gastroenterology and Nutrition, Boston Children’s Hospital, Boston, Massachusetts, USA
- Department of Pediatrics, Harvard Medical School, Boston, Massachusetts, USA
- Harvard Digestive Disease Center, Boston Children’s Hospital, Boston, Massachusetts, USA
| | - Heidi De Luca
- Division of Gastroenterology and Nutrition, Boston Children’s Hospital, Boston, Massachusetts, USA
| | - Doyle V. Ward
- Department of Microbiology and Physiological Systems, and
- Program in Microbiome Dynamics, University of Massachusetts Chan Medical School, Worcester, Massachusetts, USA
| | - Irini A.M. Kreulen
- Division of Gastroenterology and Nutrition, Boston Children’s Hospital, Boston, Massachusetts, USA
| | - Katlynn Bugda Gwilt
- Division of Gastroenterology and Nutrition, Boston Children’s Hospital, Boston, Massachusetts, USA
| | - Sage E. Foley
- Department of Microbiology and Physiological Systems, and
- Program in Microbiome Dynamics, University of Massachusetts Chan Medical School, Worcester, Massachusetts, USA
| | - Jay R. Thiagarajah
- Division of Gastroenterology and Nutrition, Boston Children’s Hospital, Boston, Massachusetts, USA
- Department of Pediatrics, Harvard Medical School, Boston, Massachusetts, USA
- Harvard Digestive Disease Center, Boston Children’s Hospital, Boston, Massachusetts, USA
| | - Beth A. McCormick
- Department of Microbiology and Physiological Systems, and
- Program in Microbiome Dynamics, University of Massachusetts Chan Medical School, Worcester, Massachusetts, USA
| | - Jerrold R. Turner
- Harvard Digestive Disease Center, Boston Children’s Hospital, Boston, Massachusetts, USA
- Laboratory of Mucosal Barrier Pathobiology, Department of Pathology, Brigham and Women’s Hospital, Boston, Massachusetts, USA
- Departments of Pathology and Medicine, Harvard Medical School, Boston, Massachusetts, USA
| | - Wayne I. Lencer
- Division of Gastroenterology and Nutrition, Boston Children’s Hospital, Boston, Massachusetts, USA
- Department of Pediatrics, Harvard Medical School, Boston, Massachusetts, USA
- Harvard Digestive Disease Center, Boston Children’s Hospital, Boston, Massachusetts, USA
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10
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Zhong Y, Yan W, Ruan J, Fang M, Yu C, Du S, Rai G, Tao D, Henderson MJ, Fang S. XBP1 variant 1 promotes mitosis of cancer cells involving upregulation of the polyglutamylase TTLL6. Hum Mol Genet 2022; 31:2639-2654. [PMID: 35333353 PMCID: PMC9396943 DOI: 10.1093/hmg/ddac010] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2021] [Revised: 12/19/2021] [Accepted: 01/10/2022] [Indexed: 11/15/2022] Open
Abstract
XBP1 variant 1 (Xv1) is the most abundant XBP1 variant and is highly enriched across cancer types but nearly none in normal tissues. Its expression is associated with poor patients' survival and is specifically required for survival of malignant cells, but the underlying mechanism is not known. Here we report that Xv1 upregulates the polyglutamylase tubulin tyrosine ligase-like 6 (TTLL6) and promotes mitosis of cancer cells. Like the canonical XBP1, Xv1 mRNA undergoes unconventional splicing by IRE1α under endoplasmic reticulum stress, but it is also constitutively spliced by IRE1β. The spliced Xv1 mRNA encodes the active form of Xv1 protein (Xv1s). RNA sequencing in HeLa cells revealed that Xv1s overexpression regulates expression of genes that are not involved in the canonical unfolded protein response, including TTLL6 as a highly upregulated gene. Gel shift assay and chromatin immunoprecipitation revealed that Xv1s bind to the TTLL6 promoter region. Knockdown of TTLL6 caused death of cancer cells but not benign and normal cells, similar to the effects of knocking down Xv1. Moreover, overexpression of TTLL6 partially rescued BT474 cells from apoptosis induced by either TTLL6 or Xv1 knockdown, supporting TTLL6 as an essential downstream effector of Xv1 in regulating cancer cell survival. TTLL6 is localized in the mitotic spindle of cancer cells. Xv1 or TTLL6 knockdown resulted in decreased spindle polyglutamylation and interpolar spindle, as well as congression failure, mitotic arrest and cell death. These findings suggest that Xv1 is essential for cancer cell mitosis, which is mediated, at least in part, by increasing TTLL6 expression.
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Affiliation(s)
- Yongwang Zhong
- Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
- Department of Physiology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Wenjing Yan
- Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
- Department of Physiology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Jingjing Ruan
- Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
- Department of Pulmonary Medicine, Anhui Medical University First Affiliated Hospital, Hefei, Anhui 230032, China
| | - Mike Fang
- Population and Quantitative Health Sciences Department, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Changjun Yu
- Department of General surgery, Anhui Medical University First Affiliated Hospital, Hefei, Anhui 230032, China
| | - Shaojun Du
- Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Ganesha Rai
- National Center for Advancing Translational Sciences, National Institutes of Health, Rockville, MD 20850, USA
| | - Dingyin Tao
- National Center for Advancing Translational Sciences, National Institutes of Health, Rockville, MD 20850, USA
| | - Mark J Henderson
- National Center for Advancing Translational Sciences, National Institutes of Health, Rockville, MD 20850, USA
| | - Shengyun Fang
- Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
- Department of Physiology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
- Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
- Program in Oncology, UM Greenebaum Comprehensive Cancer Center, University of Maryland School of Medicine, Baltimore, MD 21201, USA
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11
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Rangwala AM, Mingione VR, Georghiou G, Seeliger MA. Kinases on Double Duty: A Review of UniProtKB Annotated Bifunctionality within the Kinome. Biomolecules 2022; 12:biom12050685. [PMID: 35625613 PMCID: PMC9138534 DOI: 10.3390/biom12050685] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2022] [Revised: 05/03/2022] [Accepted: 05/09/2022] [Indexed: 01/27/2023] Open
Abstract
Phosphorylation facilitates the regulation of all fundamental biological processes, which has triggered extensive research of protein kinases and their roles in human health and disease. In addition to their phosphotransferase activity, certain kinases have evolved to adopt additional catalytic functions, while others have completely lost all catalytic activity. We searched the Universal Protein Resource Knowledgebase (UniProtKB) database for bifunctional protein kinases and focused on kinases that are critical for bacterial and human cellular homeostasis. These kinases engage in diverse functional roles, ranging from environmental sensing and metabolic regulation to immune-host defense and cell cycle control. Herein, we describe their dual catalytic activities and how they contribute to disease pathogenesis.
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12
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Trouvé P, Férec C, Génin E. The Interplay between the Unfolded Protein Response, Inflammation and Infection in Cystic Fibrosis. Cells 2021; 10:2980. [PMID: 34831204 PMCID: PMC8616505 DOI: 10.3390/cells10112980] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2021] [Revised: 10/25/2021] [Accepted: 10/29/2021] [Indexed: 12/15/2022] Open
Abstract
In cystic fibrosis (CF), p.Phe508del is the most frequent mutation in the Cystic Fibrosis Transmembrane conductance Regulator (CFTR) gene. The p.Phe508del-CFTR protein is retained in the ER and rapidly degraded. This retention likely triggers an atypical Unfolded Protein Response (UPR) involving ATF6, which reduces the expression of p.Phe508del-CFTR. There are still some debates on the role of the UPR in CF: could it be triggered by the accumulation of misfolded CFTR proteins in the endoplasmic reticulum as was proposed for the most common CFTR mutation p.Phe508del? Or, is it the consequence of inflammation and infection that occur in the disease? In this review, we summarize recent findings on UPR in CF and show how infection, inflammation and UPR act together in CF. We propose to rethink their respective role in CF and to consider them as a whole.
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Affiliation(s)
- Pascal Trouvé
- Inserm, Univ Brest, EFS, UMR 1078, GGB, F-29200 Brest, France; (C.F.); (E.G.)
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13
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Pharmacological targeting of endoplasmic reticulum stress in disease. Nat Rev Drug Discov 2021; 21:115-140. [PMID: 34702991 DOI: 10.1038/s41573-021-00320-3] [Citation(s) in RCA: 152] [Impact Index Per Article: 50.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/15/2021] [Indexed: 02/08/2023]
Abstract
The accumulation of misfolded proteins in the endoplasmic reticulum (ER) leads to ER stress, resulting in activation of the unfolded protein response (UPR) that aims to restore protein homeostasis. However, the UPR also plays an important pathological role in many diseases, including metabolic disorders, cancer and neurological disorders. Over the last decade, significant effort has been invested in targeting signalling proteins involved in the UPR and an array of drug-like molecules is now available. However, these molecules have limitations, the understanding of which is crucial for their development into therapies. Here, we critically review the existing ER stress and UPR-directed drug-like molecules, highlighting both their value and their limitations.
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14
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Fenech EJ, Ben-Dor S, Schuldiner M. Double the Fun, Double the Trouble: Paralogs and Homologs Functioning in the Endoplasmic Reticulum. Annu Rev Biochem 2021; 89:637-666. [PMID: 32569522 DOI: 10.1146/annurev-biochem-011520-104831] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The evolution of eukaryotic genomes has been propelled by a series of gene duplication events, leading to an expansion in new functions and pathways. While duplicate genes may retain some functional redundancy, it is clear that to survive selection they cannot simply serve as a backup but rather must acquire distinct functions required for cellular processes to work accurately and efficiently. Understanding these differences and characterizing gene-specific functions is complex. Here we explore different gene pairs and families within the context of the endoplasmic reticulum (ER), the main cellular hub of lipid biosynthesis and the entry site for the secretory pathway. Focusing on each of the ER functions, we highlight specificities of related proteins and the capabilities conferred to cells through their conservation. More generally, these examples suggest why related genes have been maintained by evolutionary forces and provide a conceptual framework to experimentally determine why they have survived selection.
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Affiliation(s)
- Emma J Fenech
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot 7610001, Israel;
| | - Shifra Ben-Dor
- Department of Life Sciences Core Facilities, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Maya Schuldiner
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot 7610001, Israel;
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15
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The Unfolded Protein Response: An Overview. BIOLOGY 2021; 10:biology10050384. [PMID: 33946669 PMCID: PMC8146082 DOI: 10.3390/biology10050384] [Citation(s) in RCA: 122] [Impact Index Per Article: 40.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/30/2021] [Revised: 04/23/2021] [Accepted: 04/27/2021] [Indexed: 12/11/2022]
Abstract
Simple Summary The unfolded protein response (UPR) is the cells’ way of maintaining the balance of protein folding in the endoplasmic reticulum, which is the section of the cell designated for folding proteins with specific destinations such as other organelles or to be secreted by the cell. The UPR is activated when unfolded proteins accumulate in the endoplasmic reticulum. This accumulation puts a greater load on the molecules in charge of folding the proteins, and therefore the UPR works to balance this by lowering the number of unfolded proteins present in the cell. This is done in multiple ways, such as lowering the number of proteins that need to be folded; increasing the folding ability of the endoplasmic reticulum and by removing some of the unfolded proteins which take longer to fold. If the UPR is successful at reducing the number of unfolded proteins, the UPR is inactivated and the cells protein folding balance is returned to normal. However, if the UPR is unsuccessful, then this can lead to cell death. Abstract The unfolded protein response is the mechanism by which cells control endoplasmic reticulum (ER) protein homeostasis. Under normal conditions, the UPR is not activated; however, under certain stresses, such as hypoxia or altered glycosylation, the UPR can be activated due to an accumulation of unfolded proteins. The activation of the UPR involves three signaling pathways, IRE1, PERK and ATF6, which all play vital roles in returning protein homeostasis to levels seen in non-stressed cells. IRE1 is the best studied of the three pathways, as it is the only pathway present in Saccharomyces cerevisiae. This pathway involves spliceosome independent splicing of HAC1 or XBP1 in yeast and mammalians cells, respectively. PERK limits protein synthesis, therefore reducing the number of new proteins requiring folding. ATF6 is translocated and proteolytically cleaved, releasing a NH2 domain fragment which is transported to the nucleus and which affects gene expression. If the UPR is unsuccessful at reducing the load of unfolded proteins in the ER and the UPR signals remain activated, this can lead to programmed cell death.
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16
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Li W, Crotty K, Garrido Ruiz D, Voorhies M, Rivera C, Sil A, Mullins RD, Jacobson MP, Peschek J, Walter P. Protomer alignment modulates specificity of RNA substrate recognition by Ire1. eLife 2021; 10:e67425. [PMID: 33904404 PMCID: PMC8104961 DOI: 10.7554/elife.67425] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2021] [Accepted: 04/27/2021] [Indexed: 11/21/2022] Open
Abstract
The unfolded protein response (UPR) maintains protein folding homeostasis in the endoplasmic reticulum (ER). In metazoan cells, the Ire1 branch of the UPR initiates two functional outputs-non-conventional mRNA splicing and selective mRNA decay (RIDD). By contrast, Ire1 orthologs from Saccharomyces cerevisiae and Schizosaccharomyces pombe are specialized for only splicing or RIDD, respectively. Previously, we showed that the functional specialization lies in Ire1's RNase activity, which is either stringently splice-site specific or promiscuous (Li et al., 2018). Here, we developed an assay that reports on Ire1's RNase promiscuity. We found that conversion of two amino acids within the RNase domain of S. cerevisiae Ire1 to their S. pombe counterparts rendered it promiscuous. Using biochemical assays and computational modeling, we show that the mutations rewired a pair of salt bridges at Ire1 RNase domain's dimer interface, changing its protomer alignment. Thus, Ire1 protomer alignment affects its substrates specificity.
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Affiliation(s)
- Weihan Li
- Department of Biochemistry and Biophysics, University of California San FranciscoSan FranciscoUnited States
- Howard Hughes Medical InstituteSan FranciscoUnited States
| | - Kelly Crotty
- Department of Biochemistry and Biophysics, University of California San FranciscoSan FranciscoUnited States
- Howard Hughes Medical InstituteSan FranciscoUnited States
| | - Diego Garrido Ruiz
- Department of Pharmaceutical Chemistry, University of California at San FranciscoSan FranciscoUnited States
| | - Mark Voorhies
- Department of Microbiology and Immunology, University of California at San FranciscoSan FranciscoUnited States
| | - Carlos Rivera
- Department of Molecular Biophysics and Biochemistry, Yale School of MedicineNew HavenUnited States
| | - Anita Sil
- Department of Microbiology and Immunology, University of California at San FranciscoSan FranciscoUnited States
| | - R Dyche Mullins
- Howard Hughes Medical InstituteSan FranciscoUnited States
- Department of Cellular and Molecular Pharmacology, University of California at San FranciscoSan FranciscoUnited States
| | - Matthew P Jacobson
- Department of Pharmaceutical Chemistry, University of California at San FranciscoSan FranciscoUnited States
| | - Jirka Peschek
- Department of Biochemistry and Biophysics, University of California San FranciscoSan FranciscoUnited States
- Howard Hughes Medical InstituteSan FranciscoUnited States
| | - Peter Walter
- Department of Biochemistry and Biophysics, University of California San FranciscoSan FranciscoUnited States
- Howard Hughes Medical InstituteSan FranciscoUnited States
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17
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Chong WC, Shastri MD, Peterson GM, Patel RP, Pathinayake PS, Dua K, Hansbro NG, Hsu AC, Wark PA, Shukla SD, Johansen MD, Schroder K, Hansbro PM. The complex interplay between endoplasmic reticulum stress and the NLRP3 inflammasome: a potential therapeutic target for inflammatory disorders. Clin Transl Immunology 2021; 10:e1247. [PMID: 33614031 PMCID: PMC7878118 DOI: 10.1002/cti2.1247] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2020] [Revised: 01/09/2021] [Accepted: 01/10/2021] [Indexed: 12/15/2022] Open
Abstract
Inflammation is the result of a complex network of cellular and molecular interactions and mechanisms that facilitate immune protection against intrinsic and extrinsic stimuli, particularly pathogens, to maintain homeostasis and promote tissue healing. However, dysregulation in the immune system elicits excess/abnormal inflammation resulting in unintended tissue damage and causes major inflammatory diseases including asthma, chronic obstructive pulmonary disease, atherosclerosis, inflammatory bowel diseases, sarcoidosis and rheumatoid arthritis. It is now widely accepted that both endoplasmic reticulum (ER) stress and inflammasomes play critical roles in activating inflammatory signalling cascades. Notably, evidence is mounting for the involvement of ER stress in exacerbating inflammasome-induced inflammatory cascades, which may provide a new axis for therapeutic targeting in a range of inflammatory disorders. Here, we comprehensively review the roles, mechanisms and interactions of both ER stress and inflammasomes, as well as their interconnected relationships in inflammatory signalling cascades. We also discuss novel therapeutic strategies that are being developed to treat ER stress- and inflammasome-related inflammatory disorders.
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Affiliation(s)
- Wai Chin Chong
- Department of Molecular and Translational ScienceMonash UniversityClaytonVICAustralia
- Centre for Cancer ResearchHudson Institute of Medical ResearchClaytonVICAustralia
| | - Madhur D Shastri
- School of Pharmacy and PharmacologyUniversity of TasmaniaHobartTASAustralia
| | - Gregory M Peterson
- School of Pharmacy and PharmacologyUniversity of TasmaniaHobartTASAustralia
| | - Rahul P Patel
- School of Pharmacy and PharmacologyUniversity of TasmaniaHobartTASAustralia
| | - Prabuddha S Pathinayake
- Priority Research Centre for Healthy LungsHunter Medical Research InstituteThe University of NewcastleCallaghanNSWAustralia
| | - Kamal Dua
- Discipline of PharmacyGraduate School of HealthUniversity of Technology SydneyUltimoNSWAustralia
| | - Nicole G Hansbro
- Centre for InflammationCentenary InstituteFaculty of ScienceSchool of Life SciencesUniversity of TechnologySydneyNSWAustralia
| | - Alan C Hsu
- Priority Research Centre for Healthy LungsHunter Medical Research InstituteThe University of NewcastleCallaghanNSWAustralia
| | - Peter A Wark
- Priority Research Centre for Healthy LungsHunter Medical Research InstituteThe University of NewcastleCallaghanNSWAustralia
| | - Shakti Dhar Shukla
- Priority Research Centre for Healthy LungsHunter Medical Research InstituteThe University of NewcastleCallaghanNSWAustralia
| | - Matt D Johansen
- Centre for InflammationCentenary InstituteFaculty of ScienceSchool of Life SciencesUniversity of TechnologySydneyNSWAustralia
| | - Kate Schroder
- Institute for Molecular BioscienceUniversity of QueenslandSt LuciaQLDAustralia
| | - Philip M Hansbro
- Priority Research Centre for Healthy LungsHunter Medical Research InstituteThe University of NewcastleCallaghanNSWAustralia
- Centre for InflammationCentenary InstituteFaculty of ScienceSchool of Life SciencesUniversity of TechnologySydneyNSWAustralia
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18
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Kim P, Scott MR, Meador-Woodruff JH. Dysregulation of the unfolded protein response (UPR) in the dorsolateral prefrontal cortex in elderly patients with schizophrenia. Mol Psychiatry 2021; 26:1321-1331. [PMID: 31578497 PMCID: PMC7113111 DOI: 10.1038/s41380-019-0537-7] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/18/2019] [Revised: 09/10/2019] [Accepted: 09/23/2019] [Indexed: 12/12/2022]
Abstract
Abnormalities in protein localization, function, and posttranslational modifications are targets of schizophrenia (SCZ) research. As a major contributor to the synthesis, folding, trafficking, and modification of proteins, the endoplasmic reticulum (ER) is well-positioned to sense cellular stress. The unfolded protein response (UPR) is an evolutionarily conserved adaptive reaction to environmental and pathological perturbation in ER function. The UPR is a highly orchestrated and complex cellular response, which is mediated through the ER chaperone protein, BiP, three known ER transmembrane stress sensors, protein kinase RNA-like ER kinase (PERK), activating transcription factor-6 (ATF6), inositol requiring enzyme 1α (IRE1α), and their downstream effectors. In this study, we measured protein expression and phosphorylation states of UPR sensor pathway proteins in the dorsolateral prefrontal cortex (DLPFC) of 22 matched pairs of elderly SCZ and comparison subjects. We observed increased protein expression of BiP, decreased PERK, and decreased phosphorylation of IRE1α. We also observed decreased p-JNK2 and increased sXBP1, downstream targets of the IRE1α arm of the UPR. The disconnect between decreased p-IRE1α and increased sXBP1 protein expression led us to measure sXbp1 mRNA. We observed increased expression of the ratio of sXbp1/uXbp1 transcripts, suggesting that splicing of Xbp1 mRNA by IRE1α is increased and drives upregulation of sXBP1 protein expression. These findings suggest an abnormal pattern of UPR activity in SCZ, with specific dysregulation of the IRE1α arm. Dysfunction of this system may lead to abnormal responses to cellular stressors and contribute to protein processing abnormalities previously observed in SCZ.
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Affiliation(s)
- Pitna Kim
- Department of Psychiatry and Behavioral Neurobiology, University of Alabama at Birmingham, Birmingham, AL, 35294, USA.
| | - Madeline R. Scott
- grid.265892.20000000106344187Department of Psychiatry and Behavioral Neurobiology, University of Alabama at Birmingham, Birmingham, AL 35294 USA
| | - James H. Meador-Woodruff
- grid.265892.20000000106344187Department of Psychiatry and Behavioral Neurobiology, University of Alabama at Birmingham, Birmingham, AL 35294 USA
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19
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Evolution and function of the epithelial cell-specific ER stress sensor IRE1β. Mucosal Immunol 2021; 14:1235-1246. [PMID: 34075183 PMCID: PMC8528705 DOI: 10.1038/s41385-021-00412-8] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2021] [Revised: 04/30/2021] [Accepted: 05/01/2021] [Indexed: 02/04/2023]
Abstract
Barrier epithelial cells lining the mucosal surfaces of the gastrointestinal and respiratory tracts interface directly with the environment. As such, these tissues are continuously challenged to maintain a healthy equilibrium between immunity and tolerance against environmental toxins, food components, and microbes. An extracellular mucus barrier, produced and secreted by the underlying epithelium plays a central role in this host defense response. Several dedicated molecules with a unique tissue-specific expression in mucosal epithelia govern mucosal homeostasis. Here, we review the biology of Inositol-requiring enzyme 1β (IRE1β), an ER-resident endonuclease and paralogue of the most evolutionarily conserved ER stress sensor IRE1α. IRE1β arose through gene duplication in early vertebrates and adopted functions unique from IRE1α which appear to underlie the basic development and physiology of mucosal tissues.
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20
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Intestinal Immune Homeostasis and Inflammatory Bowel Disease: A Perspective on Intracellular Response Mechanisms. GASTROINTESTINAL DISORDERS 2020. [DOI: 10.3390/gidisord2030024] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The pathogenesis of inflammatory bowel disease (IBD) involves perturbation of intestinal immune homeostasis in genetically susceptible individuals. A mutual interplay between intestinal epithelial cells (IECs) and gut resident microbes maintains a homeostatic environment across the gut. An idiopathic gastrointestinal (GI) complication triggers aberrant physiological stress in the epithelium and peripheral myeloid cells, leading to a chronic inflammatory condition. Indeed, events in the endoplasmic reticulum (ER) and mitochondria contribute to orchestrating intracellular mechanisms such as the unfolded protein response (UPR) and oxidative stress, respectively, to resolve aberrant cellular stress. This review highlights the signaling cascades encrypted within ER and mitochondria in IECs and/or myeloid cells to dissipate chronic stress in maintaining intestinal homeostasis.
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21
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Riaz TA, Junjappa RP, Handigund M, Ferdous J, Kim HR, Chae HJ. Role of Endoplasmic Reticulum Stress Sensor IRE1α in Cellular Physiology, Calcium, ROS Signaling, and Metaflammation. Cells 2020; 9:E1160. [PMID: 32397116 PMCID: PMC7290600 DOI: 10.3390/cells9051160] [Citation(s) in RCA: 46] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2020] [Revised: 04/27/2020] [Accepted: 05/06/2020] [Indexed: 12/14/2022] Open
Abstract
Inositol-requiring transmembrane kinase endoribonuclease-1α (IRE1α) is the most prominent and evolutionarily conserved unfolded protein response (UPR) signal transducer during endoplasmic reticulum functional upset (ER stress). A IRE1α signal pathway arbitrates yin and yang of cellular fate in objectionable conditions. It plays several roles in fundamental cellular physiology as well as in several pathological conditions such as diabetes, obesity, inflammation, cancer, neurodegeneration, and in many other diseases. Thus, further understanding of its molecular structure and mechanism of action during different cell insults helps in designing and developing better therapeutic strategies for the above-mentioned chronic diseases. In this review, recent insights into structure and mechanism of activation of IRE1α along with its complex regulating network were discussed in relation to their basic cellular physiological function. Addressing different binding partners that can modulate IRE1α function, UPRosome triggers different downstream pathways depending on the cellular backdrop. Furthermore, IRE1α are in normal cell activities outside the dominion of ER stress and activities under the weather of inflammation, diabetes, and obesity-related metaflammation. Thus, IRE1 as an ER stress sensor needs to be understood from a wider perspective for comprehensive functional meaning, which facilitates us with assembling future needs and therapeutic benefits.
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Affiliation(s)
- Thoufiqul Alam Riaz
- Department of Pharmacology, School of Medicine, Institute of New Drug Development, Jeonbuk National University, Jeonju 54907, Korea; (T.A.R.); (R.P.J.)
| | - Raghu Patil Junjappa
- Department of Pharmacology, School of Medicine, Institute of New Drug Development, Jeonbuk National University, Jeonju 54907, Korea; (T.A.R.); (R.P.J.)
| | - Mallikarjun Handigund
- Department of Laboratory Medicine, Jeonbuk National University, Medical School, Jeonju 54907, Korea;
| | - Jannatul Ferdous
- Department of Radiology and Research Institute of Clinical Medicine of Jeonbuk National University, Biomedical Research Institute of Jeonbuk National University Hospital, Jeonju 54907, Korea;
| | - Hyung-Ryong Kim
- College of Dentistry, Dankook University, Cheonan 31116, Korea
| | - Han-Jung Chae
- Department of Pharmacology, School of Medicine, Institute of New Drug Development, Jeonbuk National University, Jeonju 54907, Korea; (T.A.R.); (R.P.J.)
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22
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Jaud M, Philippe C, Di Bella D, Tang W, Pyronnet S, Laurell H, Mazzolini L, Rouault-Pierre K, Touriol C. Translational Regulations in Response to Endoplasmic Reticulum Stress in Cancers. Cells 2020; 9:cells9030540. [PMID: 32111004 PMCID: PMC7140484 DOI: 10.3390/cells9030540] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2019] [Revised: 02/18/2020] [Accepted: 02/24/2020] [Indexed: 12/20/2022] Open
Abstract
During carcinogenesis, almost all the biological processes are modified in one way or another. Among these biological processes affected, anomalies in protein synthesis are common in cancers. Indeed, cancer cells are subjected to a wide range of stresses, which include physical injuries, hypoxia, nutrient starvation, as well as mitotic, oxidative or genotoxic stresses. All of these stresses will cause the accumulation of unfolded proteins in the Endoplasmic Reticulum (ER), which is a major organelle that is involved in protein synthesis, preservation of cellular homeostasis, and adaptation to unfavourable environment. The accumulation of unfolded proteins in the endoplasmic reticulum causes stress triggering an unfolded protein response in order to promote cell survival or to induce apoptosis in case of chronic stress. Transcription and also translational reprogramming are tightly controlled during the unfolded protein response to ensure selective gene expression. The majority of stresses, including ER stress, induce firstly a decrease in global protein synthesis accompanied by the induction of alternative mechanisms for initiating the translation of mRNA, later followed by a translational recovery. After a presentation of ER stress and the UPR response, we will briefly present the different modes of translation initiation, then address the specific translational regulatory mechanisms acting during reticulum stress in cancers and highlight the importance of translational control by ER stress in tumours.
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Affiliation(s)
- Manon Jaud
- Inserm UMR1037, CRCT (Cancer Research Center of Toulouse), F-31037 Toulouse, France; (M.J.); (S.P.); (L.M.)
- Université Toulouse III Paul-Sabatier, F-31000 Toulouse, France;
| | - Céline Philippe
- Barts Cancer Institute, Queen Mary University of London, London E1 4NS, UK; (C.P.); (D.D.B.); (W.T.); (K.R.-P.)
| | - Doriana Di Bella
- Barts Cancer Institute, Queen Mary University of London, London E1 4NS, UK; (C.P.); (D.D.B.); (W.T.); (K.R.-P.)
| | - Weiwei Tang
- Barts Cancer Institute, Queen Mary University of London, London E1 4NS, UK; (C.P.); (D.D.B.); (W.T.); (K.R.-P.)
| | - Stéphane Pyronnet
- Inserm UMR1037, CRCT (Cancer Research Center of Toulouse), F-31037 Toulouse, France; (M.J.); (S.P.); (L.M.)
- Université Toulouse III Paul-Sabatier, F-31000 Toulouse, France;
| | - Henrik Laurell
- Université Toulouse III Paul-Sabatier, F-31000 Toulouse, France;
- Inserm UMR1048, I2MC (Institut des Maladies Métaboliques et Cardiovasculaires), BP 84225, CEDEX 04, 31 432 Toulouse, France
| | - Laurent Mazzolini
- Inserm UMR1037, CRCT (Cancer Research Center of Toulouse), F-31037 Toulouse, France; (M.J.); (S.P.); (L.M.)
- CNRS ERL5294, CRCT, F-31037 Toulouse, France
| | - Kevin Rouault-Pierre
- Barts Cancer Institute, Queen Mary University of London, London E1 4NS, UK; (C.P.); (D.D.B.); (W.T.); (K.R.-P.)
| | - Christian Touriol
- Inserm UMR1037, CRCT (Cancer Research Center of Toulouse), F-31037 Toulouse, France; (M.J.); (S.P.); (L.M.)
- Université Toulouse III Paul-Sabatier, F-31000 Toulouse, France;
- Correspondence:
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23
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Grey MJ, Cloots E, Simpson MS, LeDuc N, Serebrenik YV, De Luca H, De Sutter D, Luong P, Thiagarajah JR, Paton AW, Paton JC, Seeliger MA, Eyckerman S, Janssens S, Lencer WI. IRE1β negatively regulates IRE1α signaling in response to endoplasmic reticulum stress. J Cell Biol 2020; 219:133656. [PMID: 31985747 PMCID: PMC7041686 DOI: 10.1083/jcb.201904048] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2019] [Revised: 09/27/2019] [Accepted: 11/25/2019] [Indexed: 12/26/2022] Open
Abstract
IRE1β is an ER stress sensor uniquely expressed in epithelial cells lining mucosal surfaces. Here, we show that intestinal epithelial cells expressing IRE1β have an attenuated unfolded protein response to ER stress. When modeled in HEK293 cells and with purified protein, IRE1β diminishes expression and inhibits signaling by the closely related stress sensor IRE1α. IRE1β can assemble with and inhibit IRE1α to suppress stress-induced XBP1 splicing, a key mediator of the unfolded protein response. In comparison to IRE1α, IRE1β has relatively weak XBP1 splicing activity, largely explained by a nonconserved amino acid in the kinase domain active site that impairs its phosphorylation and restricts oligomerization. This enables IRE1β to act as a dominant-negative suppressor of IRE1α and affect how barrier epithelial cells manage the response to stress at the host-environment interface.
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Affiliation(s)
- Michael J Grey
- Division of Gastroenterology, Hepatology, and Nutrition, Boston Children's Hospital, Boston, MA.,Harvard Medical School, Boston, MA.,Harvard Digestive Disease Center, Boston, MA
| | - Eva Cloots
- VIB-UGent Center for Medical Biotechnology and Department of Biomolecular Medicine, Ghent University, Ghent, Belgium.,Laboratory for ER stress and Inflammation, VIB-UGent Center for Inflammation Research and Department of Internal Medicine and Pediatrics, Ghent University, Ghent, Belgium
| | - Mariska S Simpson
- Division of Gastroenterology, Hepatology, and Nutrition, Boston Children's Hospital, Boston, MA.,Graduate School of Life Sciences, Utrecht University, Utrecht, Netherlands
| | - Nicole LeDuc
- Division of Gastroenterology, Hepatology, and Nutrition, Boston Children's Hospital, Boston, MA
| | - Yevgeniy V Serebrenik
- Department of Molecular, Cellular, and Developmental Biology, Yale University, New Haven, CT
| | - Heidi De Luca
- Division of Gastroenterology, Hepatology, and Nutrition, Boston Children's Hospital, Boston, MA
| | - Delphine De Sutter
- VIB-UGent Center for Medical Biotechnology and Department of Biomolecular Medicine, Ghent University, Ghent, Belgium
| | - Phi Luong
- Division of Gastroenterology, Hepatology, and Nutrition, Boston Children's Hospital, Boston, MA
| | - Jay R Thiagarajah
- Division of Gastroenterology, Hepatology, and Nutrition, Boston Children's Hospital, Boston, MA.,Harvard Medical School, Boston, MA.,Harvard Digestive Disease Center, Boston, MA
| | - Adrienne W Paton
- Research Centre for Infectious Diseases, Department of Molecular and Biomedical Science, University of Adelaide, Adelaide, Australia
| | - James C Paton
- Research Centre for Infectious Diseases, Department of Molecular and Biomedical Science, University of Adelaide, Adelaide, Australia
| | - Markus A Seeliger
- Department of Pharmacological Sciences, Stony Brook University Medical School, Stony Brook, NY
| | - Sven Eyckerman
- VIB-UGent Center for Medical Biotechnology and Department of Biomolecular Medicine, Ghent University, Ghent, Belgium
| | - Sophie Janssens
- Laboratory for ER stress and Inflammation, VIB-UGent Center for Inflammation Research and Department of Internal Medicine and Pediatrics, Ghent University, Ghent, Belgium
| | - Wayne I Lencer
- Division of Gastroenterology, Hepatology, and Nutrition, Boston Children's Hospital, Boston, MA.,Harvard Medical School, Boston, MA.,Harvard Digestive Disease Center, Boston, MA
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24
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Feldman HC, Vidadala VN, Potter ZE, Papa FR, Backes BJ, Maly DJ. Development of a Chemical Toolset for Studying the Paralog-Specific Function of IRE1. ACS Chem Biol 2019; 14:2595-2605. [PMID: 31609569 PMCID: PMC6925334 DOI: 10.1021/acschembio.9b00482] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The dual kinase endoribonuclease IRE1 is a master regulator of cell fate decisions in cells experiencing endoplasmic reticulum (ER) stress. In mammalian cells, there are two paralogs of IRE1: IRE1α and IRE1β. While IRE1α has been extensively studied, much less is understood about IRE1β and its role in signaling. In addition, whether the regulation of IRE1β's enzymatic activities varies compared to IRE1α is not known. Here, we show that the RNase domain of IRE1β is enzymatically active and capable of cleaving an XBP1 RNA mini-substrate in vitro. Using ATP-competitive inhibitors, we find that, like IRE1α, there is an allosteric relationship between the kinase and RNase domains of IRE1β. This allowed us to develop a novel toolset of both paralog specific and dual-IRE1α/β kinase inhibitors that attenuate RNase activity (KIRAs). Using sequence alignments of IRE1α and IRE1β, we propose a model for paralog-selective inhibition through interactions with nonconserved residues that differentiate the ATP-binding pockets of IRE1α and IRE1β.
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Affiliation(s)
- Hannah C. Feldman
- Department of Chemistry, University of Washington, Seattle, Washington, United States
| | | | - Zachary E. Potter
- Department of Chemistry, University of Washington, Seattle, Washington, United States
| | - Feroz R. Papa
- Department of Medicine, University of California−San Francisco, San Francisco, California, United States
- Lung Biology Center, University of California−San Francisco, San Francisco, California, United States
- Department of Pathology, University of California−San Francisco, San Francisco, California, United States
- Diabetes Center, University of California−San Francisco, San Francisco, California, United States
- California Institute for Quantitative Biosciences, University of California−San Francisco, San Francisco, California, United States
| | - Bradley J. Backes
- Department of Medicine, University of California−San Francisco, San Francisco, California, United States
- Lung Biology Center, University of California−San Francisco, San Francisco, California, United States
| | - Dustin J. Maly
- Department of Chemistry, University of Washington, Seattle, Washington, United States
- Department of Biochemistry, University of Washington, Seattle, Washington, United States
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25
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Park CK, Horton NC. Structures, functions, and mechanisms of filament forming enzymes: a renaissance of enzyme filamentation. Biophys Rev 2019; 11:927-994. [PMID: 31734826 PMCID: PMC6874960 DOI: 10.1007/s12551-019-00602-6] [Citation(s) in RCA: 50] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2019] [Accepted: 10/24/2019] [Indexed: 12/19/2022] Open
Abstract
Filament formation by non-cytoskeletal enzymes has been known for decades, yet only relatively recently has its wide-spread role in enzyme regulation and biology come to be appreciated. This comprehensive review summarizes what is known for each enzyme confirmed to form filamentous structures in vitro, and for the many that are known only to form large self-assemblies within cells. For some enzymes, studies describing both the in vitro filamentous structures and cellular self-assembly formation are also known and described. Special attention is paid to the detailed structures of each type of enzyme filament, as well as the roles the structures play in enzyme regulation and in biology. Where it is known or hypothesized, the advantages conferred by enzyme filamentation are reviewed. Finally, the similarities, differences, and comparison to the SgrAI endonuclease system are also highlighted.
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Affiliation(s)
- Chad K. Park
- Department of Molecular and Cellular Biology, University of Arizona, Tucson, AZ 85721 USA
| | - Nancy C. Horton
- Department of Molecular and Cellular Biology, University of Arizona, Tucson, AZ 85721 USA
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26
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Chen G, Ribeiro CMP, Sun L, Okuda K, Kato T, Gilmore RC, Martino MB, Dang H, Abzhanova A, Lin JM, Hull-Ryde EA, Volmer AS, Randell SH, Livraghi-Butrico A, Deng Y, Scherer PE, Stripp BR, O’Neal WK, Boucher RC. XBP1S Regulates MUC5B in a Promoter Variant-Dependent Pathway in Idiopathic Pulmonary Fibrosis Airway Epithelia. Am J Respir Crit Care Med 2019; 200:220-234. [PMID: 30973754 PMCID: PMC6635783 DOI: 10.1164/rccm.201810-1972oc] [Citation(s) in RCA: 43] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2018] [Accepted: 04/11/2019] [Indexed: 02/05/2023] Open
Abstract
Rationale: The goal was to connect elements of idiopathic pulmonary fibrosis (IPF) pathogenesis, including chronic endoplasmic reticulum stress in respiratory epithelia associated with injury/inflammation and remodeling, distal airway mucus obstruction and honeycomb cyst formation with accumulation of MUC5B (mucin 5B), and associations between IPF risk and polymorphisms in the MUC5B promoter. Objectives: To test whether the endoplasmic reticulum (ER) stress sensor protein ERN2 (ER-to-nucleus signaling 2) and its downstream effector, the spliced form of XBP1S (X-box-binding protein 1), regulate MUC5B expression and differentially activate the MUC5B promoter variant in respiratory epithelia. Methods: Primary human airway epithelial (HAE) cells, transgenic mouse models, human IPF lung tissues, and cell lines expressing XBP1S and MUC5B promoters were used to explore relationships between the ERN2/XBP1S pathway and MUC5B. An inhibitor of the pathway, KIRA6, and XBP1 CRISPR-Cas9 were used in HAE cells to explore therapeutic potential. Measurements and Main Results: ERN2 regulated MUC5B and MUC5AC mRNAs. Downstream XBP1S selectively promoted MUC5B expression in vitro and in distal murine airway epithelia in vivo. XBP1S bound to the proximal region of the MUC5B promoter and differentially upregulated MUC5B expression in the context of the MUC5B promoter rs35705950 variant. High levels of ERN2 and XBP1S were associated with excessive MUC5B mRNAs in distal airways of human IPF lungs. Cytokine-induced MUC5B expression in HAE cells was inhibited by KIRA6 and XBP1 CRISPR-Cas9. Conclusions: A positive feedback bistable ERN2-XBP1S pathway regulates MUC5B-dominated mucus obstruction in IPF, providing an unfolded protein response-dependent mechanism linking the MUC5B promoter rs35705950 polymorphism with IPF pathogenesis. Inhibiting ERN2-dependent pathways/elements may provide a therapeutic option for IPF.
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Affiliation(s)
- Gang Chen
- Marsico Lung Institute and Cystic Fibrosis Research Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
| | - Carla M. P. Ribeiro
- Marsico Lung Institute and Cystic Fibrosis Research Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
| | - Ling Sun
- Marsico Lung Institute and Cystic Fibrosis Research Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
- Research Center of Regeneration Medicine, West China Hospital, Sichuan University, Chengdu, Sichuan Province, China
| | - Kenichi Okuda
- Marsico Lung Institute and Cystic Fibrosis Research Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
| | - Takafumi Kato
- Marsico Lung Institute and Cystic Fibrosis Research Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
| | - Rodney C. Gilmore
- Marsico Lung Institute and Cystic Fibrosis Research Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
| | - Mary B. Martino
- Marsico Lung Institute and Cystic Fibrosis Research Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
| | - Hong Dang
- Marsico Lung Institute and Cystic Fibrosis Research Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
| | - Aiman Abzhanova
- Marsico Lung Institute and Cystic Fibrosis Research Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
| | - Jennifer M. Lin
- Marsico Lung Institute and Cystic Fibrosis Research Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
| | - Emily A. Hull-Ryde
- Center of Integrative Chemical Biology and Drug Discovery, University of North Carolina Eshelman School of Pharmacy, Chapel Hill, North Carolina
| | - Allison S. Volmer
- Marsico Lung Institute and Cystic Fibrosis Research Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
| | - Scott H. Randell
- Marsico Lung Institute and Cystic Fibrosis Research Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
| | - Alessandra Livraghi-Butrico
- Marsico Lung Institute and Cystic Fibrosis Research Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
| | - Yingfeng Deng
- Department of Internal Medicine, Touchstone Diabetes Center, University of Texas Southwestern Medical Center, Dallas, Texas; and
| | - Philipp E. Scherer
- Department of Internal Medicine, Touchstone Diabetes Center, University of Texas Southwestern Medical Center, Dallas, Texas; and
| | - Barry R. Stripp
- Pulmonary Research, Cedars Sinai Medical Center, Los Angeles, California
| | - Wanda K. O’Neal
- Marsico Lung Institute and Cystic Fibrosis Research Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
| | - Richard C. Boucher
- Marsico Lung Institute and Cystic Fibrosis Research Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
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27
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Endoplasmic reticulum proteostasis control and gastric cancer. Cancer Lett 2019; 449:263-271. [PMID: 30776479 DOI: 10.1016/j.canlet.2019.01.034] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2018] [Revised: 01/16/2019] [Accepted: 01/26/2019] [Indexed: 02/07/2023]
Abstract
The endoplasmic reticulum (ER) is the primary organelle responsible for the synthesis, modification, folding and secretion of proteins, especially in specialized secretory cells. It also contributes to the maintenance of cellular functions, such as Ca2+ storage, lipogenesis, gluconeogenesis, and organelle biogenesis. Cellular stress conditions, such as glucose deprivation, hypoxia and disturbance of Ca2+ homeostasis, may increase the risk of protein misfolding and perturb proteostasis. This activates ER stress and triggers the unfolded protein response (UPR), leading to either the restoration of homeostasis or cell death. ER stress and UPR have been shown to play crucial roles in the pathogenesis, progression and treatment response of various cancers. In gastric cancer (GC), one of the most aggressive cancer types, critical functions of ER stress signaling have also started to emerge. Herein, we summarize the current knowledge linking ER stress and UPR to GC; we also discuss the possible nodes of therapeutic intervention and propose directions of future research.
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28
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Dickens JA, Malzer E, Chambers JE, Marciniak SJ. Pulmonary endoplasmic reticulum stress-scars, smoke, and suffocation. FEBS J 2019; 286:322-341. [PMID: 29323786 DOI: 10.1111/febs.14381] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2017] [Revised: 12/11/2017] [Accepted: 01/08/2018] [Indexed: 12/14/2022]
Abstract
Protein misfolding within the endoplasmic reticulum (ER stress) can be a cause or consequence of pulmonary disease. Mutation of proteins restricted to the alveolar type II pneumocyte can lead to inherited forms of pulmonary fibrosis, but even sporadic cases of pulmonary fibrosis appear to be strongly associated with activation of the unfolded protein response and/or the integrated stress response. Inhalation of smoke can impair protein folding and may be an important cause of pulmonary ER stress. Similarly, tissue hypoxia can lead to impaired protein homeostasis (proteostasis). But the mechanisms linking smoke and hypoxia to ER stress are only partially understood. In this review, we will examine the role of ER stress in the pathogenesis of lung disease by focusing on fibrosis, smoke, and hypoxia.
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Affiliation(s)
- Jennifer A Dickens
- Cambridge Institute for Medical Research (CIMR), University of Cambridge, UK
| | - Elke Malzer
- Cambridge Institute for Medical Research (CIMR), University of Cambridge, UK
| | - Joseph E Chambers
- Cambridge Institute for Medical Research (CIMR), University of Cambridge, UK
| | - Stefan J Marciniak
- Cambridge Institute for Medical Research (CIMR), University of Cambridge, UK
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29
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Ishiwata-Kimata Y, Le GQ, Kimata Y. Stress-sensing and regulatory mechanism of the endoplasmic-stress sensors Ire1 and PERK. ENDOPLASMIC RETICULUM STRESS IN DISEASES 2018. [DOI: 10.1515/ersc-2018-0001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Abstract
Ire1 and its family protein PERK are endoplasmic reticulum (ER)-stress sensors that initiate cellular responses against ER accumulation of unfolded proteins. As reviewed in this article, many publications describe molecular mechanisms by which yeast Ire1 senses ER conditions and gets regulated. We also cover recent studies which reveal that mammalian Ire1 (IRE1α) and PERK are controlled in a similar but not exactly the same manner. ER-located molecular chaperone BiP captures these ER-stress sensors and suppresses their activity. Intriguingly, Ire1 is associated with BiP not as a chaperone substrate, but as a unique ligand. Unfolded proteins accumulated in the ER promote dissociation of the Ire1-BiP complex. Moreover, Ire1 is directly bound with unfolded proteins, leading to its cluster formation and potent activation. PERK also captures unfolded proteins and then forms self-oligomers. Meanwhile, membrane-lipid aberrancy is likely to activate these ER-stress sensors independently of ER accumulation of unfolded proteins. In addition, there exist a number of reports that touch on other factors that control activity of these ER-stress sensors. Such a multiplicity of regulatory mechanisms for these ER-stress sensors is likely to contribute to fine tuning of their activity.
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30
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Almanza A, Carlesso A, Chintha C, Creedican S, Doultsinos D, Leuzzi B, Luís A, McCarthy N, Montibeller L, More S, Papaioannou A, Püschel F, Sassano ML, Skoko J, Agostinis P, de Belleroche J, Eriksson LA, Fulda S, Gorman AM, Healy S, Kozlov A, Muñoz-Pinedo C, Rehm M, Chevet E, Samali A. Endoplasmic reticulum stress signalling - from basic mechanisms to clinical applications. FEBS J 2018; 286:241-278. [PMID: 30027602 PMCID: PMC7379631 DOI: 10.1111/febs.14608] [Citation(s) in RCA: 506] [Impact Index Per Article: 84.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2018] [Revised: 06/24/2018] [Accepted: 07/18/2018] [Indexed: 02/06/2023]
Abstract
The endoplasmic reticulum (ER) is a membranous intracellular organelle and the first compartment of the secretory pathway. As such, the ER contributes to the production and folding of approximately one‐third of cellular proteins, and is thus inextricably linked to the maintenance of cellular homeostasis and the fine balance between health and disease. Specific ER stress signalling pathways, collectively known as the unfolded protein response (UPR), are required for maintaining ER homeostasis. The UPR is triggered when ER protein folding capacity is overwhelmed by cellular demand and the UPR initially aims to restore ER homeostasis and normal cellular functions. However, if this fails, then the UPR triggers cell death. In this review, we provide a UPR signalling‐centric view of ER functions, from the ER's discovery to the latest advancements in the understanding of ER and UPR biology. Our review provides a synthesis of intracellular ER signalling revolving around proteostasis and the UPR, its impact on other organelles and cellular behaviour, its multifaceted and dynamic response to stress and its role in physiology, before finally exploring the potential exploitation of this knowledge to tackle unresolved biological questions and address unmet biomedical needs. Thus, we provide an integrated and global view of existing literature on ER signalling pathways and their use for therapeutic purposes.
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Affiliation(s)
- Aitor Almanza
- Apoptosis Research Centre, National University of Ireland, Galway, Ireland
| | - Antonio Carlesso
- Department of Chemistry and Molecular Biology, University of Gothenburg, Göteborg, Sweden
| | - Chetan Chintha
- Apoptosis Research Centre, National University of Ireland, Galway, Ireland
| | | | - Dimitrios Doultsinos
- INSERM U1242, University of Rennes, France.,Centre de Lutte Contre le Cancer Eugène Marquis, Rennes, France
| | - Brian Leuzzi
- Apoptosis Research Centre, National University of Ireland, Galway, Ireland
| | - Andreia Luís
- Ludwig Boltzmann Institute for Experimental and Clinical Traumatology, AUVA Research Centre, Vienna, Austria
| | - Nicole McCarthy
- Institute for Experimental Cancer Research in Paediatrics, Goethe-University, Frankfurt, Germany
| | - Luigi Montibeller
- Neurogenetics Group, Division of Brain Sciences, Faculty of Medicine, Imperial College London, UK
| | - Sanket More
- Department Cellular and Molecular Medicine, Laboratory of Cell Death and Therapy, KU Leuven, Belgium
| | - Alexandra Papaioannou
- INSERM U1242, University of Rennes, France.,Centre de Lutte Contre le Cancer Eugène Marquis, Rennes, France
| | - Franziska Püschel
- Cell Death Regulation Group, Oncobell Program, Bellvitge Biomedical Research Institute (IDIBELL), Barcelona, Spain
| | - Maria Livia Sassano
- Department Cellular and Molecular Medicine, Laboratory of Cell Death and Therapy, KU Leuven, Belgium
| | - Josip Skoko
- Institute of Cell Biology and Immunology, University of Stuttgart, Germany
| | - Patrizia Agostinis
- Department Cellular and Molecular Medicine, Laboratory of Cell Death and Therapy, KU Leuven, Belgium
| | - Jackie de Belleroche
- Neurogenetics Group, Division of Brain Sciences, Faculty of Medicine, Imperial College London, UK
| | - Leif A Eriksson
- Department of Chemistry and Molecular Biology, University of Gothenburg, Göteborg, Sweden
| | - Simone Fulda
- Institute for Experimental Cancer Research in Paediatrics, Goethe-University, Frankfurt, Germany
| | - Adrienne M Gorman
- Apoptosis Research Centre, National University of Ireland, Galway, Ireland
| | - Sandra Healy
- Apoptosis Research Centre, National University of Ireland, Galway, Ireland
| | - Andrey Kozlov
- Ludwig Boltzmann Institute for Experimental and Clinical Traumatology, AUVA Research Centre, Vienna, Austria
| | - Cristina Muñoz-Pinedo
- Cell Death Regulation Group, Oncobell Program, Bellvitge Biomedical Research Institute (IDIBELL), Barcelona, Spain
| | - Markus Rehm
- Institute of Cell Biology and Immunology, University of Stuttgart, Germany
| | - Eric Chevet
- INSERM U1242, University of Rennes, France.,Centre de Lutte Contre le Cancer Eugène Marquis, Rennes, France
| | - Afshin Samali
- Apoptosis Research Centre, National University of Ireland, Galway, Ireland
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31
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Li W, Okreglak V, Peschek J, Kimmig P, Zubradt M, Weissman JS, Walter P. Engineering ER-stress dependent non-conventional mRNA splicing. eLife 2018; 7:35388. [PMID: 29985129 PMCID: PMC6037481 DOI: 10.7554/elife.35388] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2018] [Accepted: 06/16/2018] [Indexed: 12/26/2022] Open
Abstract
The endoplasmic reticulum (ER) protein folding capacity is balanced with the protein folding burden to prevent accumulation of un- or misfolded proteins. The ER membrane-resident kinase/RNase Ire1 maintains ER protein homeostasis through two fundamentally distinct processes. First, Ire1 can initiate a transcriptional response through a non-conventional mRNA splicing reaction to increase the ER folding capacity. Second, Ire1 can decrease the ER folding burden through selective mRNA decay. In Saccharomyces cerevisiae and Schizosaccharomyces pombe, the two Ire1 functions have been evolutionarily separated. Here, we show that the respective Ire1 orthologs have become specialized for their functional outputs by divergence of their RNase specificities. In addition, RNA structural features separate the splicing substrates from the decay substrates. Using these insights, we engineered an S. pombe Ire1 cleavage substrate into a splicing substrate, which confers S. pombe with both Ire1 functional outputs.
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Affiliation(s)
- Weihan Li
- Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, United States.,Howard Hughes Medical Institute, San Francisco, United States
| | - Voytek Okreglak
- Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, United States.,Howard Hughes Medical Institute, San Francisco, United States
| | - Jirka Peschek
- Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, United States.,Howard Hughes Medical Institute, San Francisco, United States
| | - Philipp Kimmig
- Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, United States.,Howard Hughes Medical Institute, San Francisco, United States
| | - Meghan Zubradt
- Howard Hughes Medical Institute, San Francisco, United States.,Department of Cellular and Molecular Pharmacology, University of California, San Francisco, San Francisco, United States
| | - Jonathan S Weissman
- Howard Hughes Medical Institute, San Francisco, United States.,Department of Cellular and Molecular Pharmacology, University of California, San Francisco, San Francisco, United States
| | - Peter Walter
- Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, United States.,Howard Hughes Medical Institute, San Francisco, United States
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32
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Kadowaki H, Nishitoh H. Endoplasmic reticulum quality control by garbage disposal. FEBS J 2018; 286:232-240. [PMID: 29923316 DOI: 10.1111/febs.14589] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2018] [Revised: 06/12/2018] [Accepted: 06/18/2018] [Indexed: 11/30/2022]
Abstract
Various types of intracellular and extracellular stresses disturb homeostasis in the endoplasmic reticulum (ER) and, thus, trigger the ER stress response. Unavoidable and/or prolonged ER stress causes cell toxicity and occasionally cell death. The malfunction or death of irreplaceable cells leads to conformational diseases, including diabetes mellitus, ischemic diseases, metabolic diseases, and neurodegenerative diseases. In the past several decades, many studies have revealed the molecular mechanisms of the ER quality control system. Cells resolve ER stress by promptly and accurately reducing the amount of malfolded proteins. Recent reports have revealed that cells possess several types of ER-related disposal systems, including mRNA decay, proteasomal degradation, and autophagy. The removal of dispensable RNAs, proteins, and organelle parts may enable the effective maintenance of a functional ER. Here, we provide a comprehensive understanding of the ER quality control system by focusing on ER-related garbage disposal systems.
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Affiliation(s)
- Hisae Kadowaki
- Laboratory of Biochemistry and Molecular Biology, Department of Medical Sciences, University of Miyazaki, Japan
| | - Hideki Nishitoh
- Laboratory of Biochemistry and Molecular Biology, Department of Medical Sciences, University of Miyazaki, Japan
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33
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Shen K, Johnson DW, Vesey DA, McGuckin MA, Gobe GC. Role of the unfolded protein response in determining the fate of tumor cells and the promise of multi-targeted therapies. Cell Stress Chaperones 2018; 23:317-334. [PMID: 28952072 PMCID: PMC5904077 DOI: 10.1007/s12192-017-0844-3] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2017] [Accepted: 09/13/2017] [Indexed: 02/06/2023] Open
Abstract
Although there have been advances in our understanding of carcinogenesis and development of new treatments, cancer remains a common cause of death. Many regulatory pathways are incompletely understood in cancer development and progression, with a prime example being those related to the endoplasmic reticulum (ER). The pathological sequelae that arise from disruption of ER homeostasis are not well defined. The ER is an organelle that is responsible for secretory protein biosynthesis and the quality control of protein folding. The ER triggers an unfolded protein response (UPR) when misfolded proteins accumulate, and while the UPR acts to restore protein folding and ER homeostasis, this response can work as a switch to determine the death or survival of cells. The treatment of cancer with agents that target the UPR has shown promising outcomes. The UPR has wide crosstalk with other signaling pathways. Multi-targeted cancer therapies which target the intersections within signaling networks have shown synergistic tumoricidal effects. In the present review, the basic cellular and signaling pathways of the ER and UPR are introduced; then the crosstalk between the ER and other signaling pathways is summarized; and ultimately, the evidence that the UPR is a potential target for cancer therapy is discussed. Regulation of the UPR downstream signaling is a common therapeutic target for different tumor types. Tumoricidal effects achieved from modulating the UPR downstream signaling could be enhanced by phosphodiesterase 5 (PDE5) inhibitors. Largely untapped by Western medicine for cancer therapies are Chinese herbal medicines. This review explores and discusses the value of some Chinese herbal extracts as PDE5 inhibitors.
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Affiliation(s)
- Kunyu Shen
- Kidney Disease Research Group, UQ Diamantina Institute, Translational Research Institute, The University of Queensland, 37 Kent Street, Woolloongabba, Brisbane, 4102, Australia
| | - David W Johnson
- Kidney Disease Research Group, UQ Diamantina Institute, Translational Research Institute, The University of Queensland, 37 Kent Street, Woolloongabba, Brisbane, 4102, Australia
- Department of Nephrology, Princess Alexandra Hospital, Woolloongabba, Brisbane, Australia
- Centre for Health Services Research, Faculty of Medicine, The University of Queensland, Brisbane, Australia
| | - David A Vesey
- Department of Nephrology, Princess Alexandra Hospital, Woolloongabba, Brisbane, Australia
- Centre for Health Services Research, Faculty of Medicine, The University of Queensland, Brisbane, Australia
| | - Michael A McGuckin
- Mucosal Disease Inflammatory Disease Biology and Therapeutics Group, UQ Mater Research Institute, Translational Research Institute, The University of Queensland, Brisbane, QLD, Australia
| | - Glenda C Gobe
- Kidney Disease Research Group, UQ Diamantina Institute, Translational Research Institute, The University of Queensland, 37 Kent Street, Woolloongabba, Brisbane, 4102, Australia.
- Centre for Health Services Research, Faculty of Medicine, The University of Queensland, Brisbane, Australia.
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34
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The Unfolded Protein Response in Chronic Obstructive Pulmonary Disease. Ann Am Thorac Soc 2018; 13 Suppl 2:S138-45. [PMID: 27115948 DOI: 10.1513/annalsats.201506-320kv] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
Accumulation of nonfunctional and potentially cytotoxic, misfolded proteins in chronic obstructive pulmonary disease (COPD) is believed to contribute to lung cell apoptosis, inflammation, and autophagy. Because of its fundamental role as a quality control system in protein metabolism, the "unfolded protein response" (UPR) is of potential importance in the pathogenesis of COPD. The UPR comprises a series of transcriptional, translational, and post-translational processes that decrease protein synthesis while enhancing protein folding capacity and protein degradation. Several studies have suggested that the UPR contributes to lung cell apoptosis and lung inflammation in at least some subjects with human COPD. However, information on the prevalence of the UPR in subjects with COPD, the lung cells that manifest a UPR, and the role of the UPR in the pathogenesis of COPD is extremely limited and requires additional study.
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35
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Pinkaew D, Chattopadhyay A, King MD, Chunhacha P, Liu Z, Stevenson HL, Chen Y, Sinthujaroen P, McDougal OM, Fujise K. Fortilin binds IRE1α and prevents ER stress from signaling apoptotic cell death. Nat Commun 2017; 8:18. [PMID: 28550308 PMCID: PMC5446404 DOI: 10.1038/s41467-017-00029-1] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2016] [Accepted: 04/05/2017] [Indexed: 12/19/2022] Open
Abstract
The endoplasmic reticulum, the cytoplasmic organelle that matures a massive amount of nascent secretory polypeptides, is particularly sensitive to stress. Endoplasmic reticulum stress causes unfolded proteins to populate the organelle, eliciting the unfolded protein response. During the unfolded protein response, GRP78—an endoplasmic reticulum master stress regulator—detaches from three endoplasmic reticulum stress sensors (IRE1α, PERK, and ATF6) and allows them to activate the apoptotic signaling pathway. Fortilin, a pro-survival molecule, is known to inhibit apoptosis by binding and inhibiting p53, but its role in endoplasmic reticulum stress-induced apoptosis remains unknown. Here, we report that fortilin directly interacts with the cytoplasmic domain of IRE1α, inhibits both kinase and endoribonuclease (RNase) activities of the stress sensor, and protects cells against apoptotic cell death at both cellular and whole animal levels. Our data support a role of fortilin in the unfolded protein response and its potential participation in human diseases caused by unfolded protein response. IRE1α is an ER stress sensor, whose activity induces apoptosis. Here, the authors report that fortilin, a pro-survival factor, with yet unknown roles in ER stress, interacts with active IRE1α, inhibits both its kinase end RNase activities, and protects cells from apoptosis both in vitro and in vivo.
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Affiliation(s)
- Decha Pinkaew
- Division of Cardiology, Department of Internal Medicine, University of Texas Medical Branch at Galveston, Galveston, Texas, 77555, USA
| | - Abhijnan Chattopadhyay
- Division of Cardiology, Department of Internal Medicine, University of Texas Medical Branch at Galveston, Galveston, Texas, 77555, USA.,Department of Biochemistry and Molecular Biology, University of Texas Medical Branch at Galveston, Galveston, Texas, 77555, USA
| | - Matthew D King
- Department of Chemistry and Biochemistry, Boise State University, Boise, Idaho, 83725, USA
| | - Preedakorn Chunhacha
- Division of Cardiology, Department of Internal Medicine, University of Texas Medical Branch at Galveston, Galveston, Texas, 77555, USA
| | - Zhihe Liu
- Division of Cardiology, Department of Internal Medicine, University of Texas Medical Branch at Galveston, Galveston, Texas, 77555, USA
| | - Heather L Stevenson
- Department of Pathology, University of Texas Medical Branch at Galveston, Galveston, Texas, 77555, USA.,The Institute of Translational Sciences, University of Texas Medical Branch at Galveston, Galveston, Texas, 77555, USA
| | - Yanjie Chen
- Division of Cardiology, Department of Internal Medicine, University of Texas Medical Branch at Galveston, Galveston, Texas, 77555, USA
| | - Patuma Sinthujaroen
- Division of Cardiology, Department of Internal Medicine, University of Texas Medical Branch at Galveston, Galveston, Texas, 77555, USA
| | - Owen M McDougal
- Department of Chemistry and Biochemistry, Boise State University, Boise, Idaho, 83725, USA
| | - Ken Fujise
- Division of Cardiology, Department of Internal Medicine, University of Texas Medical Branch at Galveston, Galveston, Texas, 77555, USA. .,Department of Biochemistry and Molecular Biology, University of Texas Medical Branch at Galveston, Galveston, Texas, 77555, USA. .,The Institute of Translational Sciences, University of Texas Medical Branch at Galveston, Galveston, Texas, 77555, USA.
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36
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Ojha R, Amaravadi RK. Targeting the unfolded protein response in cancer. Pharmacol Res 2017; 120:258-266. [PMID: 28396092 DOI: 10.1016/j.phrs.2017.04.003] [Citation(s) in RCA: 79] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/26/2016] [Revised: 03/31/2017] [Accepted: 04/06/2017] [Indexed: 01/22/2023]
Abstract
Cancer cells are exposed to various intrinsic and extrinsic factors that disrupt protein homeostasis, producing endoplasmic reticulum (ER) stress. To cope with these situations, cancer cells evoke a highly conserved adaptive mechanism called the unfolded protein response (UPR) to restore the ER homeostasis. Recently, several pharmacological agents have been found to exhibit anti-tumor activity by targeting the UPR components. The development of potent and specific compounds that target the UPR components has not only shed light on the regulation of the UPR in cancer cells, but also brought the field closer to clinical drug candidates. Here we present an overview of the milestones in the field of UPR biology in cancer with a focus on new strategies for pharmacological inhibition.
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Affiliation(s)
- Rani Ojha
- Department of Medicine and Abramson Cancer Center, University of Pennsylvania, United States
| | - Ravi K Amaravadi
- Department of Medicine and Abramson Cancer Center, University of Pennsylvania, United States.
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37
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Jiang Y, Zhou Y, Zheng Y, Guo H, Gao L, Chen P, Feng D, Qi R, Li X, Chang Y, Chu FF, Gao Q. Expression of inositol-requiring enzyme 1β is downregulated in colorectal cancer. Oncol Lett 2017; 13:1109-1118. [PMID: 28454221 PMCID: PMC5403352 DOI: 10.3892/ol.2017.5590] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2015] [Accepted: 09/12/2016] [Indexed: 12/22/2022] Open
Abstract
The endoplasmic reticulum stress inositol-requiring enzyme (IRE) 1α/X-box binding protein (XBP) 1 signaling pathway is involved in the tumorigenesis of breast and prostate cancer. Mucin 2 (MUC2) protects colon tissues from the formation of tumors. In human colorectal cancer (CRC) the role of IRE1α, and its analogue, IRE1β, has yet to be elucidated. In the present study, the expression levels of IRE1α, IRE1β, un-spliced XBP1u, spliced XBP1s and MUC2 in surgically resected cancerous and adjacent non-cancerous tissues from patients with CRC were investigated. The IRE1α, IRE1β, XBP1u, XBP1s and MUC2 mRNA expression levels were determined using reverse transcription-quantitative polymerase chain reaction, and the protein expression levels were detected using immunohistochemistry and western blotting. The association between the expression levels of IRE1α, IRE1β and MUC2 and the clinicopathological features of patients with CRC was subsequently analyzed. The mRNA expression levels of IRE1β and MUC2 were decreased by ~2.1 and ~4.5-fold in CRC tissues, respectively, as compared with the adjacent normal tissues. The protein expression levels of IRE1β and MUC2 were decreased by ~8.0 and ~2.0-fold in the CRC tissues, respectively. IRE1β mRNA expression levels were positively correlated with MUC2 mRNA expression levels. IRE1β expression levels were revealed to be significantly associated with lymph node metastasis, tumor stage and histological differentiation. However, IRE1α, XBP1u and XBP1s mRNA and IRE1α protein expression levels were not observed to significantly differ between cancerous tissues and the adjacent normal tissues. The results indicated that the expression of IRE1β, but not IRE1α, may protect colon tissue from developing CRC by inducing MUC2 expression. Therefore, decreased IRE1β expression levels may be associated with the development of CRC through the inhibition of MUC2 expression.
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Affiliation(s)
- Yalin Jiang
- Department of Gastroenterology and Hepatology, The First Affiliated Hospital and College of Clinical Medicine, Henan University of Science and Technology, Luoyang, Henan 471023, P.R. China.,Department of Clinical Laboratory, The First Affiliated Hospital and College of Clinical Medicine, Henan University of Science and Technology, Luoyang, Henan 471023, P.R. China
| | - Yunfeng Zhou
- Shenzhen University Health Science Center, Shenzhen, Guangdong 518060, P.R. China
| | - Yufeng Zheng
- Department of Gastroenterology and Hepatology, The First Affiliated Hospital and College of Clinical Medicine, Henan University of Science and Technology, Luoyang, Henan 471023, P.R. China
| | - Hong Guo
- Department of Gastroenterology and Hepatology, The First Affiliated Hospital and College of Clinical Medicine, Henan University of Science and Technology, Luoyang, Henan 471023, P.R. China
| | - Lei Gao
- Department of Gastroenterology and Hepatology, The First Affiliated Hospital and College of Clinical Medicine, Henan University of Science and Technology, Luoyang, Henan 471023, P.R. China
| | - Pan Chen
- Department of Gastroenterology and Hepatology, The First Affiliated Hospital and College of Clinical Medicine, Henan University of Science and Technology, Luoyang, Henan 471023, P.R. China
| | - Dandan Feng
- Department of Gastroenterology and Hepatology, The First Affiliated Hospital and College of Clinical Medicine, Henan University of Science and Technology, Luoyang, Henan 471023, P.R. China
| | - Ran Qi
- Department of Gastroenterology and Hepatology, The First Affiliated Hospital and College of Clinical Medicine, Henan University of Science and Technology, Luoyang, Henan 471023, P.R. China
| | - Xiaozhen Li
- Department of Gastroenterology and Hepatology, The First Affiliated Hospital and College of Clinical Medicine, Henan University of Science and Technology, Luoyang, Henan 471023, P.R. China
| | - Yongchao Chang
- Department of Clinical Laboratory, The First Affiliated Hospital and College of Clinical Medicine, Henan University of Science and Technology, Luoyang, Henan 471023, P.R. China
| | - Fong-Fong Chu
- Department of Gastroenterology and Hepatology, The First Affiliated Hospital and College of Clinical Medicine, Henan University of Science and Technology, Luoyang, Henan 471023, P.R. China
| | - Qiang Gao
- Department of Gastroenterology and Hepatology, The First Affiliated Hospital and College of Clinical Medicine, Henan University of Science and Technology, Luoyang, Henan 471023, P.R. China
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The Unfolded Protein Response in the Immune Cell Development: Putting the Caretaker in the Driving Seat. Curr Top Microbiol Immunol 2017; 414:45-72. [PMID: 28702709 DOI: 10.1007/82_2017_1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
The endoplasmic reticulum (ER) is the primary site for the folding of proteins destined for the membranous compartment and the extracellular space. This elaborate function is coordinated by the unfolded protein response (UPR), a stress-activated cellular program that governs proteostasis. In multicellular organisms, cells have adopted specialized functions, which required functional adaptations of the ER and its UPR. Recently, it has become clear that in immune cells, the UPR has acquired functions that stretch far beyond its original scope. In this review, we will discuss the role of the UPR in the immune system and highlight the plasticity of this signaling cascade throughout immune cell development .
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Kamada Y, Nawata Y, Sugimoto Y. Lysozyme Mutants Accumulate in Cells while Associated at their N-terminal Alpha-domain with the Endoplasmic Reticulum Chaperone GRP78/BiP. Int J Biol Sci 2016; 12:184-97. [PMID: 26884716 PMCID: PMC4737675 DOI: 10.7150/ijbs.13710] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2015] [Accepted: 11/09/2015] [Indexed: 01/07/2023] Open
Abstract
Amyloidogenic human lysozyme variants deposit in cells and cause systemic amyloidosis. We recently observed that such lysozymes accumulate in the endoplasmic reticulum (ER) with the ER chaperone GRP78/BiP, accompanying the ER stress response. Here we investigated the region of lysozyme that is critical to its association with GRP78/BiP. In addition to the above-mentioned variants of lysozyme, we constructed lysozyme truncation or substitution mutants. These were co-expressed with GRP78/BiP (tagged with FLAG) in cultured human embryonic kidney cells, which were analyzed by western blotting and immunocytochemistry using anti-lysozyme and anti-FLAG antibodies. The amyloidogenic variants were confirmed to be strongly associated with GRP78/BiP as revealed by the co-immunoprecipitation assay, whereas N-terminal mutants pruned of 1-41 or 1-51 residues were found not to be associated with the chaperone. Single amino acid substitutions for the leucine array along the α-helices in the N-terminal region resulted in wild-type lysozyme remaining attached to GRP78/BiP. These mutations also tended to show lowered secretion ability. We conclude that the N-terminal α-helices region of the lysozyme is pivotal for its strong adhesion to GRP78/BiP. We suspect that wild-type lysozyme interacts with the GRP at this region as a step in the proper folding monitored by the ER chaperone.
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Affiliation(s)
- Yoshiki Kamada
- Laboratory of Biochemistry and Bioscience, The United Graduate School of Agricultural Sciences, Kagoshima University, Kagoshima 890-0065, Japan
| | - Yusuke Nawata
- Laboratory of Biochemistry and Bioscience, The United Graduate School of Agricultural Sciences, Kagoshima University, Kagoshima 890-0065, Japan
| | - Yasushi Sugimoto
- Laboratory of Biochemistry and Bioscience, The United Graduate School of Agricultural Sciences, Kagoshima University, Kagoshima 890-0065, Japan
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40
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Lencer WI, DeLuca H, Grey MJ, Cho JA. Innate immunity at mucosal surfaces: the IRE1-RIDD-RIG-I pathway. Trends Immunol 2015; 36:401-9. [PMID: 26093676 PMCID: PMC4490948 DOI: 10.1016/j.it.2015.05.006] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2015] [Revised: 05/13/2015] [Accepted: 05/14/2015] [Indexed: 12/25/2022]
Abstract
Recent studies have linked the ER stress sensor IRE1α with the RIG-I pathway, which triggers an inflammatory response upon detection of viral RNAs. In response to ER dysfunction, IRE1α cleaves mRNA into single-strand fragments that lack markers of self, which activate RIG-I. Certain microbial products from mucosal pathogens activate this pathway by binding IRE1α directly, and the discovery that IRE1 is amplified at mucosal surfaces by gene duplication suggests an important role for IRE1 in mucosal immunity. Here, we review evidence in support of this hypothesis, and propose a model wherein IRE1 surveys the integrity of the ER, acting as a guard receptor and a pattern recognition receptor, capable both of sensing cellular stress caused by microbial infection and of responding to pathogens directly.
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Affiliation(s)
- Wayne I Lencer
- Department of Pediatrics, Harvard Medical School and Boston Children's Hospital, Boston, MA, USA; Harvard Digestive Diseases Center, Boston, MA, USA.
| | - Heidi DeLuca
- Department of Pediatrics, Harvard Medical School and Boston Children's Hospital, Boston, MA, USA
| | - Michael J Grey
- Department of Pediatrics, Harvard Medical School and Boston Children's Hospital, Boston, MA, USA
| | - Jin Ah Cho
- Department of Pediatrics, Harvard Medical School and Boston Children's Hospital, Boston, MA, USA; Harvard Digestive Diseases Center, Boston, MA, USA
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41
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Dufey E, Sepúlveda D, Rojas-Rivera D, Hetz C. Cellular Mechanisms of Endoplasmic Reticulum Stress Signaling in Health and Disease. 1. An overview. Am J Physiol Cell Physiol 2014; 307:C582-94. [DOI: 10.1152/ajpcell.00258.2014] [Citation(s) in RCA: 137] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Increased demand on the protein folding capacity of the endoplasmic reticulum (ER) engages an adaptive reaction known as the unfolded protein response (UPR). The UPR regulates protein translation and the expression of numerous target genes that contribute to restore ER homeostasis or induce apoptosis of irreversibly damaged cells. UPR signaling is highly regulated and dynamic and integrates information about the type, intensity, and duration of the stress stimuli, thereby determining cell fate. Recent advances highlight novel physiological outcomes of the UPR beyond specialized secretory cells, particularly in innate immunity, metabolism, and cell differentiation. Here we discuss studies on the fine-tuning of the UPR and its physiological role in diverse organs and diseases.
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Affiliation(s)
- Estefanie Dufey
- Biomedical Neuroscience Institute, Faculty of Medicine, University of Chile, Santiago, Chile
- Program of Cellular and Molecular Biology, Institute of Biomedical Sciences, Center for Molecular Studies of the Cell, University of Chile, Santiago, Chile
| | - Denisse Sepúlveda
- Biomedical Neuroscience Institute, Faculty of Medicine, University of Chile, Santiago, Chile
- Program of Cellular and Molecular Biology, Institute of Biomedical Sciences, Center for Molecular Studies of the Cell, University of Chile, Santiago, Chile
| | - Diego Rojas-Rivera
- Biomedical Neuroscience Institute, Faculty of Medicine, University of Chile, Santiago, Chile
- Program of Cellular and Molecular Biology, Institute of Biomedical Sciences, Center for Molecular Studies of the Cell, University of Chile, Santiago, Chile
| | - Claudio Hetz
- Biomedical Neuroscience Institute, Faculty of Medicine, University of Chile, Santiago, Chile
- Program of Cellular and Molecular Biology, Institute of Biomedical Sciences, Center for Molecular Studies of the Cell, University of Chile, Santiago, Chile
- Department of Immunology and Infectious Diseases, Harvard School of Public Health, Boston, Massachusetts; and
- Neurounion Biomedical Foundation, CENPAR, Santiago, Chile
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42
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Maurel M, Chevet E, Tavernier J, Gerlo S. Getting RIDD of RNA: IRE1 in cell fate regulation. Trends Biochem Sci 2014; 39:245-54. [PMID: 24657016 DOI: 10.1016/j.tibs.2014.02.008] [Citation(s) in RCA: 413] [Impact Index Per Article: 41.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2014] [Revised: 02/20/2014] [Accepted: 02/21/2014] [Indexed: 12/12/2022]
Abstract
Inositol-requiring enzyme 1 (IRE1) is the most conserved transducer of the unfolded protein response (UPR), a homeostatic response that preserves proteostasis. Intriguingly, via its endoribonuclease activity, IRE1 produces either adaptive or death signals. This occurs through both unconventional splicing of XBP1 mRNA and regulated IRE1-dependent decay of mRNA (RIDD). Whereas XBP1 mRNA splicing is cytoprotective in response to endoplasmic reticulum (ER) stress, RIDD has revealed many unexpected features. For instance, RIDD cleaves RNA at an XBP1-like consensus site but with an activity divergent from XBP1 mRNA splicing and can either preserve ER homeostasis or induce cell death. Here we review recent findings on RIDD and propose a model of how IRE1 RNase activity might control cell fate decisions.
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Affiliation(s)
- M Maurel
- Department of Medical Protein Research, VIB, Ghent, Belgium; Department of Biochemistry, Faculty of Medicine and Health Sciences, Ghent University, Ghent, Belgium.
| | - E Chevet
- INSERM U1053, Université Bordeaux Segalen, 33000 Bordeaux, France; Centre Régional de Lutte Contre le Cancer Eugène Marquis, 35000 Rennes, France
| | - J Tavernier
- Department of Medical Protein Research, VIB, Ghent, Belgium; Department of Biochemistry, Faculty of Medicine and Health Sciences, Ghent University, Ghent, Belgium
| | - S Gerlo
- Department of Medical Protein Research, VIB, Ghent, Belgium; Department of Biochemistry, Faculty of Medicine and Health Sciences, Ghent University, Ghent, Belgium.
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43
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Arensdorf AM, Diedrichs D, Rutkowski DT. Regulation of the transcriptome by ER stress: non-canonical mechanisms and physiological consequences. Front Genet 2013; 4:256. [PMID: 24348511 PMCID: PMC3844873 DOI: 10.3389/fgene.2013.00256] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2013] [Accepted: 11/08/2013] [Indexed: 12/29/2022] Open
Abstract
The mammalian unfolded protein response (UPR) is propagated by three ER-resident transmembrane proteins, each of which initiates a signaling cascade that ultimately culminates in production of a transcriptional activator. The UPR was originally characterized as a pathway for upregulating ER chaperones, and a comprehensive body of subsequent work has shown that protein synthesis, folding, oxidation, trafficking, and degradation are all transcriptionally enhanced by the UPR. However, the global reach of the UPR extends to genes involved in diverse physiological processes having seemingly little to do with ER protein folding, and this includes a substantial number of mRNAs that are suppressed by stress rather than stimulated. Through multiple non-canonical mechanisms emanating from each of the UPR pathways, the cell dynamically regulates transcription and mRNA degradation. Here we highlight these mechanisms and their increasingly appreciated impact on physiological processes.
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Affiliation(s)
- Angela M Arensdorf
- Department of Anatomy and Cell Biology, University of Iowa Carver College of Medicine Iowa City, IA, USA
| | - Danilo Diedrichs
- Department of Mathematics and Computer Science, Wheaton College Wheaton, IL, USA
| | - D Thomas Rutkowski
- Department of Anatomy and Cell Biology, University of Iowa Carver College of Medicine Iowa City, IA, USA ; Department of Internal Medicine, University of Iowa Carver College of Medicine Iowa City, IA, USA
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44
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Wakasa Y, Hayashi S, Takaiwa F. Effect of overexpression of kinase- or RNase-deficient OsIRE1 on the endoplasmic reticulum stress response in transgenic rice plants. PLANT SIGNALING & BEHAVIOR 2013; 8:25343. [PMID: 23803744 PMCID: PMC4002584 DOI: 10.4161/psb.25343] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
IRE1 is an endoplasmic reticulum (ER) stress sensor protein in eukaryotes. In this study, we generated transgenic rice plants overexpressing three types of OsIRE1, including wild-type OsIRE1 (IRE1-OE) and two disrupted-IRE1s deficient in either kinase activity (K519A-OE) or RNase activity (K833A-OE), under the control of a constitutive promoter. Overexpression of wild-type IRE1 induced the ER stress response in transgenic rice even under non-stress conditions, whereas K519A-OE and K833A-OE had dominant negative effects on endogenous OsIRE1 expression in these transgenic plants. These lines exhibited phenotypes that were quite similar to those of OsIRE1 knock-down rice. These observations suggest that the two types of functionally disrupted OsIRE1 proteins behave as competitive inhibitors toward the ER stress response in transgenic rice plants. Furthermore, OsIRE1 may have a vital, as yet unidentified function, as determined through the characterization of the transgenic plants generated in this study.
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45
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Cho JA, Lee AH, Platzer B, Cross BCS, Gardner BM, De Luca H, Luong P, Harding HP, Glimcher LH, Walter P, Fiebiger E, Ron D, Kagan JC, Lencer WI. The unfolded protein response element IRE1α senses bacterial proteins invading the ER to activate RIG-I and innate immune signaling. Cell Host Microbe 2013; 13:558-569. [PMID: 23684307 PMCID: PMC3766372 DOI: 10.1016/j.chom.2013.03.011] [Citation(s) in RCA: 84] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2012] [Revised: 02/20/2013] [Accepted: 03/25/2013] [Indexed: 12/24/2022]
Abstract
The plasma membrane and all membrane-bound organelles except for the Golgi and endoplasmic reticulum (ER) are equipped with pattern-recognition molecules to sense microbes or their products and induce innate immunity for host defense. Here, we report that inositol-requiring-1α (IRE1α), an ER protein that signals in the unfolded protein response (UPR), is activated to induce inflammation by binding a portion of cholera toxin as it co-opts the ER to cause disease. Other known UPR transducers, including the IRE1α-dependent transcription factor XBP1, are dispensable for this signaling. The inflammatory response depends instead on the RNase activity of IRE1α to degrade endogenous mRNA, a process termed regulated IRE1α-dependent decay (RIDD) of mRNA. The mRNA fragments produced engage retinoic-acid inducible gene 1 (RIG-I), a cytosolic sensor of RNA viruses, to activate NF-κB and interferon pathways. We propose IRE1α provides for a generalized mechanism of innate immune surveillance originating within the ER lumen.
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Affiliation(s)
- Jin A Cho
- Department of Medicine, Division of GI Cell Biology, Boston Children's Hospital, Boston, MA 02115, USA
| | - Ann-Hwee Lee
- Harvard Digestive Diseases Center, Harvard Medical School, Boston, MA 02115, USA; Department of Pathology and Laboratory Medicine, Weill Cornell Medical College, New York, NY 10065, USA
| | - Barbara Platzer
- Department of Medicine, Division of GI Cell Biology, Boston Children's Hospital, Boston, MA 02115, USA
| | - Benedict C S Cross
- University of Cambridge Metabolic Research Laboratories and NIHR Cambridge Biomedical Research Centre, Cambridge CB2 0QQ, UK
| | - Brooke M Gardner
- Department of Biochemistry and Biophysics, University of California, San Francisco, CA 94158-2517, USA
| | - Heidi De Luca
- Department of Medicine, Division of GI Cell Biology, Boston Children's Hospital, Boston, MA 02115, USA
| | - Phi Luong
- Department of Medicine, Division of GI Cell Biology, Boston Children's Hospital, Boston, MA 02115, USA
| | - Heather P Harding
- University of Cambridge Metabolic Research Laboratories and NIHR Cambridge Biomedical Research Centre, Cambridge CB2 0QQ, UK
| | - Laurie H Glimcher
- Harvard Digestive Diseases Center, Harvard Medical School, Boston, MA 02115, USA; Department of Medicine, Weill Cornell Medical College, New York, NY 10065, USA
| | - Peter Walter
- Department of Biochemistry and Biophysics, University of California, San Francisco, CA 94158-2517, USA; Howard Hughes Medical Institute
| | - Edda Fiebiger
- Department of Medicine, Division of GI Cell Biology, Boston Children's Hospital, Boston, MA 02115, USA; Harvard Digestive Diseases Center, Harvard Medical School, Boston, MA 02115, USA
| | - David Ron
- University of Cambridge Metabolic Research Laboratories and NIHR Cambridge Biomedical Research Centre, Cambridge CB2 0QQ, UK
| | - Jonathan C Kagan
- Department of Medicine, Division of GI Cell Biology, Boston Children's Hospital, Boston, MA 02115, USA; Harvard Digestive Diseases Center, Harvard Medical School, Boston, MA 02115, USA
| | - Wayne I Lencer
- Department of Medicine, Division of GI Cell Biology, Boston Children's Hospital, Boston, MA 02115, USA; Harvard Digestive Diseases Center, Harvard Medical School, Boston, MA 02115, USA.
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46
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Abstract
Inflammation of human bronchial epithelia (HBE) activates the endoplasmic reticulum (ER) stress transducer inositol-requiring enzyme 1 (IRE1)α, resulting in IRE1α-mediated cytokine production. Previous studies demonstrated ubiquitous expression of IRE1α and gut-restricted expression of IRE1β. We found that IRE1β is also expressed in HBE, is absent in human alveolar cells, and is upregulated in cystic fibrosis and asthmatic HBE. Studies with Ire1β(-/-) mice and Calu-3 airway epithelia exhibiting IRE1β knockdown or overexpression revealed that IRE1β is expressed in airway mucous cells, is functionally required for airway mucin production, and this function is specific for IRE1β vs. IRE1α. IRE1β-dependent mucin production is mediated, at least in part, by activation of the transcription factor X-box binding protein-1 (XBP-1) and the resulting XBP-1-dependent transcription of anterior gradient homolog 2, a gene implicated in airway and intestinal epithelial mucin production. These novel findings suggest that IRE1β is a potential mucous cell-specific therapeutic target for airway diseases characterized by mucin overproduction.
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47
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Abstract
The respiratory tract has a surface area of approximately 70 m(2) that is in direct contact with the external environment. Approximately 12,000 l of air are inhaled daily, exposing the airway epithelium to up to 25 million particles an hour. Several inhaled environmental triggers, like cigarette smoke, diesel exhaust, or allergens, are known inducers of endoplasmatic reticulum (ER) stress and cause a dysregulation in ER homeostasis. Furthermore, some epithelial cell types along the respiratory tract have a secretory function, producing large amounts of mucus or pulmonary surfactant, as well as innate host defense molecules like defensins. To keep up with their secretory demands, these cells must rely on the appropriate functioning and folding capacity of the ER, and they are particularly more vulnerable to conditions of unresolved ER stress. In the lung interstitium, triggering of ER stress pathways has a major impact on the functioning of vascular smooth muscle cells and fibroblasts, causing aberrant dedifferentiation and proliferation. Given the large amounts of foreign material inhaled, the lung is densely populated by various types of immune cells specialized in engulfing and killing pathogens and in secreting cytokines/chemokines for efficient microbial clearance. Unfolded protein response signaling cascades have been shown to intersect with the functioning of immune cells at all levels. The current review aims to highlight the role of ER stress in health and disease in the lung, focusing on its impact on different structural and inflammatory cell types.
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48
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Negative feedback by IRE1β optimizes mucin production in goblet cells. Proc Natl Acad Sci U S A 2013; 110:2864-9. [PMID: 23386727 DOI: 10.1073/pnas.1212484110] [Citation(s) in RCA: 121] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
In mammals, the prototypical endoplasmic reticulum (ER) stress sensor inositol-requiring enzyme 1 (IRE1) has diverged into two paralogs. IRE1α is broadly expressed and mediates the unconventional splicing of X-box binding protein 1 (XBP1) mRNA during ER stress. By contrast, IRE1β is expressed selectively in the digestive tract, and its function remains unclear. Here, we report that IRE1β plays a distinctive role in mucin-secreting goblet cells. In IRE1β(-/-) mice, aberrant mucin 2 (MUC2) accumulated in the ER of goblet cells, accompanied by ER distension and elevated ER stress signaling such as increased XBP1 mRNA splicing. In contrast, conditional IRE1α(-/-) mice showed no such ER distension but a marked decrease in spliced XBP1 mRNA. mRNA stability assay revealed that MUC2 mRNA was greatly stabilized in IRE1β(-/-) mice. These findings suggest that in goblet cells, IRE1β, but not IRE1α, promotes efficient protein folding and secretion in the ER by optimizing the level of mRNA encoding their major secretory product, MUC2.
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49
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Evolution of the unfolded protein response. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2013; 1833:2458-63. [PMID: 23369734 DOI: 10.1016/j.bbamcr.2013.01.016] [Citation(s) in RCA: 102] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/13/2012] [Revised: 01/07/2013] [Accepted: 01/13/2013] [Indexed: 01/05/2023]
Abstract
The unfolded protein response (UPR) is a network of signaling pathways that responds to stress in the endoplasmic reticulum (ER). The general output of the UPR is to upregulate genes involved in ER function, thus restoring and/or increasing the capacity of the ER to fold and process proteins. In parallel, many organisms have mechanisms for limiting the load on the ER by attenuating translation or degrading ER-targeted mRNAs. Despite broad conservation of these signaling pathways across eukaryotes, interesting variations demonstrate a variety of mechanisms for managing ER stress. How do early-diverging protozoa respond to stress when they lack traditional transcriptional regulation? What is the role of the ER stress sensor Ire1 in fungal species that are missing its main target? Here I describe how diverse species have optimized the UPR to fit their needs. This article is part of a Special Issue entitled: Functional and structural diversity of endoplasmic reticulum.
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Wakasa Y, Hayashi S, Ozawa K, Takaiwa F. Multiple roles of the ER stress sensor IRE1 demonstrated by gene targeting in rice. Sci Rep 2012; 2:944. [PMID: 23230509 PMCID: PMC3517978 DOI: 10.1038/srep00944] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2012] [Accepted: 11/12/2012] [Indexed: 12/16/2022] Open
Abstract
The endoplasmic reticulum (ER) stress sensor, IRE1, contains a kinase domain and a ribonuclease domain. Ribonuclease mediates the unconventional splicing of mRNA encoding the transcription factor AtbZIP60 in Arabidopsis, or OsbZIP50 in rice, and thereby transduces signals from stressed ER. Here, we demonstrate the additional roles of plant IRE1 using genetically modified rice plants. Using a gene targeting system based on homologous recombination, genomic IRE1 was replaced with two types of missense alleles, leading to a defect in the kinase or ribonuclease activity of IRE1. Genetic analysis of these alleles demonstrated that the kinase activity of IRE1 plays a vital role independent of ribonuclease activity. Furthermore, the existence of ribonuclease substrates other than OsbZIP50 mRNA is demonstrated for the first time. This study provides new insights into higher plant signalling using a gene targeting approach.
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Affiliation(s)
- Yuhya Wakasa
- Genetically Modified Organism Research Center, National Institute of Agrobiological Sciences , Kannondai 2-1-2, Tsukuba, Ibaraki 305-8602, Japan
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