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Liu Z, Lu H, Zhang X, Tang S, Lin A, Han S, Ma X. NOXA exacerbates endoplasmic-reticulum-stress-induced intervertebral disc degeneration by activating apoptosis and ECM degradation. Cell Death Discov 2025; 11:257. [PMID: 40436859 PMCID: PMC12119965 DOI: 10.1038/s41420-025-02539-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2025] [Revised: 05/06/2025] [Accepted: 05/19/2025] [Indexed: 06/01/2025] Open
Abstract
Intervertebral disc degeneration (IVDD) is a prevalent condition leading to low back pain. Endoplasmic reticulum stress (ERS) is strongly linked to IVDD progression, although the underlying mechanisms remain unclear. In this study, we investigated the effects of NOXA on ERS-induced IVDD. Primary nucleus pulposus cells (NPCs) were stimulated with Thapsigargin to mimic the ERS microenvironment in IVDD. Western blot analysis, PCR, immunofluorescence, and immunohistochemistry assay were performed to measure the expression levels of PERK, NOXA, and cell apoptosis- and extracellular-matrix-degradation-relevant proteins. JC-1 fluorescent probes, terminal deoxynucleotidyl transferase dUTP nick end labeling staining, and flow cytometry were used to measure mitochondrial function and apoptosis in NPCs under ERS conditions. Magnetic resonance imaging, Safranin O staining, alcian blue staining, and immunohistochemistry were performed to estimate the effects of NOXA knockdown on acupuncture-mediated IVDD in rats at both imaging and histological levels. The results showed that ERS induced and activated the PERK pathway during IVDD development. Mechanically, ERS induced NPC apoptosis and ECM degradation by upregulating PERK expression and activating NOXA expression. The genetic overexpression of NOXA inhibited cell proliferation and increased apoptosis, whereas its knockdown decreased MCL-1 expression and alleviated IVDD degeneration in human NPCs and rat models. NOXA plays a crucial role in the PERK/NOXA/MCL-1 axis, mediating the link between ERS and IVDD. Targeting NOXA expression may be an effective method for treating IVDD, laying the foundation for future research on molecular mechanisms and the development of new therapies.
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Affiliation(s)
- Zhiming Liu
- Department of Spinal Surgery, The Affiliated Hospital of Qingdao University, Qingdao, Shandong, China
| | - Hui Lu
- Department of Spinal Surgery, The Affiliated Hospital of Qingdao University, Qingdao, Shandong, China
| | - Xianjuan Zhang
- Department of Clinical Laboratory, The Affiliated Hospital of Qingdao University, Qingdao, Shandong, China
| | - Shuai Tang
- Department of Spinal Surgery, The Affiliated Hospital of Qingdao University, Qingdao, Shandong, China
| | - Antao Lin
- Department of Spinal Surgery, The Affiliated Hospital of Qingdao University, Qingdao, Shandong, China
| | - Shuo Han
- Department of Spinal Surgery, The Affiliated Hospital of Qingdao University, Qingdao, Shandong, China.
| | - Xuexiao Ma
- Department of Spinal Surgery, The Affiliated Hospital of Qingdao University, Qingdao, Shandong, China.
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2
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Le HT, Kim Y, Kim MJ, Hyun SH, Kim H, Chung SW, Joe Y, Chung HT, Shin DM, Back SH. Phosphorylation of eIF2α suppresses the impairment of GSH/NADPH homeostasis and mitigates the activation of cell death pathways, including ferroptosis, during ER stress. Mol Cells 2025; 48:100210. [PMID: 40089158 PMCID: PMC11999272 DOI: 10.1016/j.mocell.2025.100210] [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: 10/10/2024] [Revised: 03/02/2025] [Accepted: 03/07/2025] [Indexed: 03/17/2025] Open
Abstract
eIF2α Phosphorylation helps maintain cellular homeostasis and overcome endoplasmic reticulum (ER) stress through transcriptional and translational reprogramming. This study aims to elucidate the transcriptional regulation of glutathione (GSH) and nicotinamide adenine dinucleotide phosphate hydrogen (NADPH) homeostasis through eIF2α phosphorylation and its impact on cell death during ER stress. eIF2α phosphorylation-deficient (A/A) cells exhibited decreased expression of multiple genes involved in GSH synthesis and NADPH production, leading to an exacerbated depletion of both cellular and mitochondrial GSH, as well as mitochondrial NADPH, during ER stress. Impaired GSH homeostasis resulted from deficient expression of ATF4 and/or its dependent factor, Nrf2, which are key transcription factors in the antioxidant response during ER stress. In contrast, the exacerbation of NADPH depletion may primarily be attributed to the dysregulated expression of mitochondrial serine-driven 1-carbon metabolism pathway genes, which are regulated by an unidentified eIF2α phosphorylation-dependent mechanism during ER stress. Moreover, the eIF2α phosphorylation-ATF4 axis was responsible for upregulation of ferroptosis-inhibiting genes and downregulation of ferroptosis-activating genes upon ER stress. Therefore, ER stress strongly induced ferroptosis of A/A cells, which was significantly inhibited by treatments with cell-permeable GSH and the ferroptosis inhibitor ferrostatin-1. ATF4 overexpression suppressed impairment of GSH homeostasis in A/A cells during ER stress by promoting expression of downstream target genes. Consequently, ATF4 overexpression mitigated ferroptosis as well as apoptosis of A/A cells during ER stress. Our findings underscore the importance of eIF2α phosphorylation in maintaining GSH/NADPH homeostasis and inhibiting ferroptosis through ATF4 and unidentified eIF2α phosphorylation-dependent target(s)-mediated transcriptional reprogramming during ER stress.
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Affiliation(s)
- Hien Thi Le
- School of Biological Sciences, University of Ulsan, Ulsan 44610, Korea
| | - Yonghwan Kim
- Department of Cell and Genetic Engineering, Asan Medical Center, University of Ulsan College of Medicine, Seoul 05505, Korea
| | - Mi-Jeong Kim
- School of Biological Sciences, University of Ulsan, Ulsan 44610, Korea
| | - Seung Hwa Hyun
- School of Biological Sciences, University of Ulsan, Ulsan 44610, Korea
| | - Hyeeun Kim
- School of Biological Sciences, University of Ulsan, Ulsan 44610, Korea
| | - Su Wol Chung
- School of Biological Sciences, University of Ulsan, Ulsan 44610, Korea
| | - Yeonsoo Joe
- College of Korean Medicine, Daegu Haany University, Gyeongsan 38610, Korea
| | - Hun Taeg Chung
- College of Korean Medicine, Daegu Haany University, Gyeongsan 38610, Korea
| | - Dong-Myung Shin
- Department of Cell and Genetic Engineering, Asan Medical Center, University of Ulsan College of Medicine, Seoul 05505, Korea
| | - Sung Hoon Back
- School of Biological Sciences, University of Ulsan, Ulsan 44610, Korea; Basic-Clinical Convergence Research Center, University of Ulsan, Ulsan 44610, Korea.
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3
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Barny LA, Hermanson JN, Garcia SK, Stauffer PE, Plate L. Dissecting Branch-Specific Unfolded Protein Response Activation in Drug-Tolerant BRAF-Mutant Melanoma using Data-Independent Acquisition Mass Spectrometry. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2025:2025.03.20.644425. [PMID: 40196682 PMCID: PMC11974750 DOI: 10.1101/2025.03.20.644425] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 04/09/2025]
Abstract
Cells rely on the Unfolded Protein Response (UPR) to maintain ER protein homeostasis (proteostasis) when faced with elevated levels of misfolded and aggregated proteins. The UPR is comprised of three main branches-ATF6, IRE1, and PERK-that coordinate the synthesis of proteins involved in folding, trafficking, and degradation of nascent proteins to restore ER function. Dysregulation of the UPR is linked to numerous diseases, including neurodegenerative disorders, cancer, and diabetes. Despite its importance, identifying UPR targets has been challenging due to their heterogeneous induction, which varies by cell type and tissue. Additionally, defining the magnitude and range of UPR-regulated genes is difficult because of intricate temporal regulation, feedback between UPR branches, and extensive cross-talk with other stress-signaling pathways. To comprehensively identify UPR-regulated proteins and determine their branch specificity, we developed a data-independent acquisition (DIA) liquid-chromatography mass spectrometry (LC-MS) pipeline. Our optimized workflow improved identifications of low-abundant UPR proteins and leveraged an automated SP3-based protocol on the Biomek i5 liquid handler for label-free peptide preparation. Using engineered stable cell lines that enable selective pharmacological activation of each UPR branch without triggering global UPR activation, we identified branch-specific UPR proteomic targets. These targets were subsequently applied to investigate proteomic changes in multiple patient-derived BRAF-mutant melanoma cell lines treated with a BRAF inhibitor (PLX4720, i.e., vemurafenib). Our findings revealed differential regulation of the XBP1s branch of the UPR in the BRAF-mutant melanoma cell lines after PLX4720 treatment, likely due to calcium activation, suggesting that the UPR plays a role as a non-genetic mechanism of drug tolerance in melanoma. In conclusion, the validated branch-specific UPR proteomic targets identified in this study provide a robust framework for investigating this pathway across different cell types, drug treatments, and disease conditions in a high-throughput manner.
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Affiliation(s)
- Lea A Barny
- Chemical and Physical Biology Program, Vanderbilt University Medical Center, Nashville, TN, 37235
| | - Jake N Hermanson
- Department of Biological Sciences, Vanderbilt University, Nashville, TN, 37235
| | - Sarah K Garcia
- Department of Chemistry, Vanderbilt University, Nashville, TN, 37235
| | - Philip E Stauffer
- Chemical and Physical Biology Program, Vanderbilt University Medical Center, Nashville, TN, 37235
| | - Lars Plate
- Chemical and Physical Biology Program, Vanderbilt University Medical Center, Nashville, TN, 37235
- Department of Biological Sciences, Vanderbilt University, Nashville, TN, 37235
- Department of Chemistry, Vanderbilt University, Nashville, TN, 37235
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, TN, 37232
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4
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Flury A, Aljayousi L, Park HJ, Khakpour M, Mechler J, Aziz S, McGrath JD, Deme P, Sandberg C, González Ibáñez F, Braniff O, Ngo T, Smith S, Velez M, Ramirez DM, Avnon-Klein D, Murray JW, Liu J, Parent M, Mingote S, Haughey NJ, Werneburg S, Tremblay MÈ, Ayata P. A neurodegenerative cellular stress response linked to dark microglia and toxic lipid secretion. Neuron 2025; 113:554-571.e14. [PMID: 39719704 DOI: 10.1016/j.neuron.2024.11.018] [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: 04/11/2024] [Revised: 10/22/2024] [Accepted: 11/25/2024] [Indexed: 12/26/2024]
Abstract
The brain's primary immune cells, microglia, are a leading causal cell type in Alzheimer's disease (AD). Yet, the mechanisms by which microglia can drive neurodegeneration remain unresolved. Here, we discover that a conserved stress signaling pathway, the integrated stress response (ISR), characterizes a microglia subset with neurodegenerative outcomes. Autonomous activation of ISR in microglia is sufficient to induce early features of the ultrastructurally distinct "dark microglia" linked to pathological synapse loss. In AD models, microglial ISR activation exacerbates neurodegenerative pathologies and synapse loss while its inhibition ameliorates them. Mechanistically, we present evidence that ISR activation promotes the secretion of toxic lipids by microglia, impairing neuron homeostasis and survival in vitro. Accordingly, pharmacological inhibition of ISR or lipid synthesis mitigates synapse loss in AD models. Our results demonstrate that microglial ISR activation represents a neurodegenerative phenotype, which may be sustained, at least in part, by the secretion of toxic lipids.
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Affiliation(s)
- Anna Flury
- Neuroscience Initiative, Advanced Science Research Center, The City University of New York (CUNY) Graduate Center, New York, NY 10031, USA; Graduate Program in Biology, CUNY Graduate Center, New York, NY 10016, USA
| | - Leen Aljayousi
- Neuroscience Initiative, Advanced Science Research Center, The City University of New York (CUNY) Graduate Center, New York, NY 10031, USA; Graduate Program in Biology, CUNY Graduate Center, New York, NY 10016, USA
| | - Hye-Jin Park
- Neuroscience Initiative, Advanced Science Research Center, The City University of New York (CUNY) Graduate Center, New York, NY 10031, USA
| | | | - Jack Mechler
- Neuroscience Initiative, Advanced Science Research Center, The City University of New York (CUNY) Graduate Center, New York, NY 10031, USA; Graduate Program in Biochemistry, CUNY Graduate Center, New York, NY 10016, USA
| | - Siaresh Aziz
- Neuroscience Initiative, Advanced Science Research Center, The City University of New York (CUNY) Graduate Center, New York, NY 10031, USA; Graduate Program in Biology, CUNY Graduate Center, New York, NY 10016, USA
| | - Jackson D McGrath
- Department of Ophthalmology and Visual Sciences, Kellogg Eye Center, University of Michigan, Michigan Medicine, Ann Arbor, MI 48105, USA
| | - Pragney Deme
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
| | - Colby Sandberg
- Division of Medical Sciences, University of Victoria, Victoria, BC V8P 5C4, Canada
| | | | - Olivia Braniff
- Division of Medical Sciences, University of Victoria, Victoria, BC V8P 5C4, Canada
| | - Thi Ngo
- Neuroscience Initiative, Advanced Science Research Center, The City University of New York (CUNY) Graduate Center, New York, NY 10031, USA
| | - Simira Smith
- Neuroscience Initiative, Advanced Science Research Center, The City University of New York (CUNY) Graduate Center, New York, NY 10031, USA
| | - Matthew Velez
- Neuroscience Initiative, Advanced Science Research Center, The City University of New York (CUNY) Graduate Center, New York, NY 10031, USA
| | - Denice Moran Ramirez
- Neuroscience Initiative, Advanced Science Research Center, The City University of New York (CUNY) Graduate Center, New York, NY 10031, USA; Graduate Program in Biology, CUNY Graduate Center, New York, NY 10016, USA
| | - Dvir Avnon-Klein
- Neuroscience Initiative, Advanced Science Research Center, The City University of New York (CUNY) Graduate Center, New York, NY 10031, USA
| | - John W Murray
- Columbia Center for Human Development, Center for Stem Cell Therapies, Department of Medicine, Columbia University Vagelos College of Physicians and Surgeons, New York, NY 10032, USA
| | - Jia Liu
- Neuroscience Initiative, Advanced Science Research Center, The City University of New York (CUNY) Graduate Center, New York, NY 10031, USA
| | - Martin Parent
- CERVO Brain Research Center, Québec City, QC G1E 1T2, Canada
| | - Susana Mingote
- Neuroscience Initiative, Advanced Science Research Center, The City University of New York (CUNY) Graduate Center, New York, NY 10031, USA; Graduate Program in Biology, CUNY Graduate Center, New York, NY 10016, USA
| | - Norman J Haughey
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA; Department of Psychiatry, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Sebastian Werneburg
- Department of Ophthalmology and Visual Sciences, Kellogg Eye Center, University of Michigan, Michigan Medicine, Ann Arbor, MI 48105, USA; Michigan Neuroscience Institute, Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Marie-Ève Tremblay
- Division of Medical Sciences, University of Victoria, Victoria, BC V8P 5C4, Canada; Department of Molecular Medicine, Université Laval, Québec City, QC G1V 0A6, Canada; Neurology and Neurosurgery Department, McGill University, Montréal, QC H3A 2B4, Canada; Canada Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, BC V6T 2A1, Canada; Centre for Advanced Materials and Related Technology and Institute on Aging and Lifelong Health, University of Victoria, Victoria, BC V8N 5M8, Canada
| | - Pinar Ayata
- Neuroscience Initiative, Advanced Science Research Center, The City University of New York (CUNY) Graduate Center, New York, NY 10031, USA; Graduate Program in Biology, CUNY Graduate Center, New York, NY 10016, USA; Graduate Program in Biochemistry, CUNY Graduate Center, New York, NY 10016, USA.
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5
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Le HT, Yu J, Ahn HS, Kim MJ, Chae IG, Cho HN, Kim J, Park HK, Kwon HN, Chae HJ, Kang BH, Seo JK, Kim K, Back SH. eIF2α phosphorylation-ATF4 axis-mediated transcriptional reprogramming mitigates mitochondrial impairment during ER stress. Mol Cells 2025; 48:100176. [PMID: 39756584 PMCID: PMC11786836 DOI: 10.1016/j.mocell.2024.100176] [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: 10/03/2024] [Revised: 12/24/2024] [Accepted: 12/28/2024] [Indexed: 01/07/2025] Open
Abstract
Eukaryotic translation initiation factor 2α (eIF2α) phosphorylation, which regulates all 3 unfolded protein response pathways, helps maintain cellular homeostasis and overcome endoplasmic reticulum (ER) stress through transcriptional and translational reprogramming. However, transcriptional regulation of mitochondrial homeostasis by eIF2α phosphorylation during ER stress is not fully understood. Here, we report that the eIF2α phosphorylation-activating transcription factor 4 (ATF4) axis is required for the expression of multiple transcription factors, including nuclear factor erythroid 2-related factor 2 and its target genes responsible for mitochondrial homeostasis during ER stress. eIF2α phosphorylation-deficient (A/A) cells displayed dysregulated mitochondrial dynamics and mitochondrial DNA replication, decreased expression of oxidative phosphorylation complex proteins, and impaired mitochondrial functions during ER stress. ATF4 overexpression suppressed impairment of mitochondrial homeostasis in A/A cells during ER stress by promoting the expression of downstream transcription factors and their target genes. Our findings underscore the importance of the eIF2α phosphorylation-ATF4 axis for maintaining mitochondrial homeostasis through transcriptional reprogramming during ER stress.
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Affiliation(s)
- Hien Thi Le
- School of Biological Sciences, University of Ulsan, Ulsan 44610, Korea
| | - Jiyoung Yu
- Asan Institute for Life Sciences, Asan Medical Center, Seoul 05505, Korea
| | - Hee Sung Ahn
- AMC Sciences, Asan Medical Center, Seoul 05505, Korea
| | - Mi-Jeong Kim
- School of Biological Sciences, University of Ulsan, Ulsan 44610, Korea
| | - In Gyeong Chae
- School of Biological Sciences, University of Ulsan, Ulsan 44610, Korea
| | - Hyun-Nam Cho
- School of Biological Sciences, University of Ulsan, Ulsan 44610, Korea
| | - Juhee Kim
- School of Biological Sciences, University of Ulsan, Ulsan 44610, Korea
| | - Hye-Kyung Park
- Department of Biological Sciences, School of Life Sciences, Ulsan National Institute of Science and Technology (UNIST), Ulsan 44919, Korea
| | - Hyuk Nam Kwon
- School of Biological Sciences, University of Ulsan, Ulsan 44610, Korea
| | - Han-Jung Chae
- School of Pharmacy, Jeonbuk National University, Jeonju 54896, Korea
| | - Byoung Heon Kang
- Department of Biological Sciences, School of Life Sciences, Ulsan National Institute of Science and Technology (UNIST), Ulsan 44919, Korea
| | - Jeong Kon Seo
- Central Research Facilities (UCRF), Ulsan National Institute of Science and Technology (UNIST), Ulsan 44919, Korea.
| | - Kyunggon Kim
- Department of Digital Medicine, Asan Medical Center, University of Ulsan College of Medicine, Seoul 05505, Korea.
| | - Sung Hoon Back
- Basic-Clinical Convergence Research Center, School of Biological Sciences, University of Ulsan, Ulsan 44610, Korea.
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6
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Magg V, Manetto A, Kopp K, Wu CC, Naghizadeh M, Lindner D, Eke L, Welsch J, Kallenberger SM, Schott J, Haucke V, Locker N, Stoecklin G, Ruggieri A. Turnover of PPP1R15A mRNA encoding GADD34 controls responsiveness and adaptation to cellular stress. Cell Rep 2024; 43:114069. [PMID: 38602876 DOI: 10.1016/j.celrep.2024.114069] [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: 05/25/2022] [Revised: 01/25/2024] [Accepted: 03/21/2024] [Indexed: 04/13/2024] Open
Abstract
The integrated stress response (ISR) is a key cellular signaling pathway activated by environmental alterations that represses protein synthesis to restore homeostasis. To prevent sustained damage, the ISR is counteracted by the upregulation of growth arrest and DNA damage-inducible 34 (GADD34), a stress-induced regulatory subunit of protein phosphatase 1 that mediates translation reactivation and stress recovery. Here, we uncover a novel ISR regulatory mechanism that post-transcriptionally controls the stability of PPP1R15A mRNA encoding GADD34. We establish that the 3' untranslated region of PPP1R15A mRNA contains an active AU-rich element (ARE) recognized by proteins of the ZFP36 family, promoting its rapid decay under normal conditions and stabilization for efficient expression of GADD34 in response to stress. We identify the tight temporal control of PPP1R15A mRNA turnover as a component of the transient ISR memory, which sets the threshold for cellular responsiveness and mediates adaptation to repeated stress conditions.
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Affiliation(s)
- Vera Magg
- Heidelberg University, Medical Faculty Heidelberg, Department of Infectious Diseases, Molecular Virology, Center for Integrative Infectious Disease Research, 69120 Heidelberg, Germany
| | - Alessandro Manetto
- Heidelberg University, Medical Faculty Heidelberg, Department of Infectious Diseases, Molecular Virology, Center for Integrative Infectious Disease Research, 69120 Heidelberg, Germany
| | - Katja Kopp
- Heidelberg University, Medical Faculty Heidelberg, Department of Infectious Diseases, Molecular Virology, Center for Integrative Infectious Disease Research, 69120 Heidelberg, Germany
| | - Chia Ching Wu
- Heidelberg University, Medical Faculty Heidelberg, Department of Infectious Diseases, Molecular Virology, Center for Integrative Infectious Disease Research, 69120 Heidelberg, Germany
| | - Mohsen Naghizadeh
- Heidelberg University, Medical Faculty Mannheim, Division of Biochemistry, Mannheim Institute for Innate Immunoscience (MI3) and Mannheim Cancer Center (MCC), 68167 Mannheim, Germany
| | - Doris Lindner
- Heidelberg University, Medical Faculty Mannheim, Division of Biochemistry, Mannheim Institute for Innate Immunoscience (MI3) and Mannheim Cancer Center (MCC), 68167 Mannheim, Germany
| | - Lucy Eke
- Faculty of Health and Medical Sciences, School of Biosciences and Medicine, University of Surrey, Guildford, UK
| | - Julia Welsch
- Heidelberg University, Medical Faculty Heidelberg, Department of Infectious Diseases, Molecular Virology, Center for Integrative Infectious Disease Research, 69120 Heidelberg, Germany
| | - Stefan M Kallenberger
- Digital Health Center, Berlin Institute of Health (BIH) and Charité, 10178 Berlin, Germany; Medical Oncology, National Center for Tumor Diseases, Heidelberg University, 69120 Heidelberg, Germany
| | - Johanna Schott
- Heidelberg University, Medical Faculty Mannheim, Division of Biochemistry, Mannheim Institute for Innate Immunoscience (MI3) and Mannheim Cancer Center (MCC), 68167 Mannheim, Germany
| | - Volker Haucke
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie, 13125 Berlin, Germany; Freie Universität Berlin, Faculty of Biology, Chemistry, and Pharmacy, 14195 Berlin, Germany
| | - Nicolas Locker
- Faculty of Health and Medical Sciences, School of Biosciences and Medicine, University of Surrey, Guildford, UK; The Pirbright Institute, GU24 0NF Pirbright, UK
| | - Georg Stoecklin
- Heidelberg University, Medical Faculty Mannheim, Division of Biochemistry, Mannheim Institute for Innate Immunoscience (MI3) and Mannheim Cancer Center (MCC), 68167 Mannheim, Germany; Center for Molecular Biology of Heidelberg University (ZMBH), DKFZ-ZMBH Alliance, 69120 Heidelberg, Germany.
| | - Alessia Ruggieri
- Heidelberg University, Medical Faculty Heidelberg, Department of Infectious Diseases, Molecular Virology, Center for Integrative Infectious Disease Research, 69120 Heidelberg, Germany.
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7
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Belužić R, Šimunić E, Podgorski II, Pinterić M, Hadžija MP, Balog T, Sobočanec S. Gene Expression Profiling Reveals Fundamental Sex-Specific Differences in SIRT3-Mediated Redox and Metabolic Signaling in Mouse Embryonic Fibroblasts. Int J Mol Sci 2024; 25:3868. [PMID: 38612678 PMCID: PMC11012119 DOI: 10.3390/ijms25073868] [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: 02/27/2024] [Revised: 03/27/2024] [Accepted: 03/28/2024] [Indexed: 04/14/2024] Open
Abstract
Sirt-3 is an important regulator of mitochondrial function and cellular energy homeostasis, whose function is associated with aging and various pathologies such as Alzheimer's disease, Parkinson's disease, cardiovascular diseases, and cancers. Many of these conditions show differences in incidence, onset, and progression between the sexes. In search of hormone-independent, sex-specific roles of Sirt-3, we performed mRNA sequencing in male and female Sirt-3 WT and KO mouse embryonic fibroblasts (MEFs). The aim of this study was to investigate the sex-specific cellular responses to the loss of Sirt-3. By comparing WT and KO MEF of both sexes, the differences in global gene expression patterns as well as in metabolic and stress responses associated with the loss of Sirt-3 have been elucidated. Significant differences in the activities of basal metabolic pathways were found both between genotypes and between sexes. In-depth pathway analysis of metabolic pathways revealed several important sex-specific phenomena. Male cells mount an adaptive Hif-1a response, shifting their metabolism toward glycolysis and energy production from fatty acids. Furthermore, the loss of Sirt-3 in male MEFs leads to mitochondrial and endoplasmic reticulum stress. Since Sirt-3 knock-out is permanent, male cells are forced to function in a state of persistent oxidative and metabolic stress. Female MEFs are able to at least partially compensate for the loss of Sirt-3 by a higher expression of antioxidant enzymes. The activation of neither Hif-1a, mitochondrial stress response, nor oxidative stress response was observed in female cells lacking Sirt-3. These findings emphasize the sex-specific role of Sirt-3, which should be considered in future research.
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8
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Santinelli R, Benz N, Guellec J, Quinquis F, Kocas E, Thomas J, Montier T, Ka C, Luczka-Majérus E, Sage E, Férec C, Coraux C, Trouvé P. The Inhibition of the Membrane-Bound Transcription Factor Site-1 Protease (MBTP1) Alleviates the p.Phe508del-Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) Defects in Cystic Fibrosis Cells. Cells 2024; 13:185. [PMID: 38247876 PMCID: PMC10814821 DOI: 10.3390/cells13020185] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2023] [Revised: 12/27/2023] [Accepted: 01/11/2024] [Indexed: 01/23/2024] Open
Abstract
Cystic Fibrosis (CF) is present due to mutations in the Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) gene, the most frequent variant being p.phe508del. The CFTR protein is a chloride (Cl-) channel which is defective and almost absent of cell membranes when the p.Phe508del mutation is present. The p.Phe508del-CFTR protein is retained in the endoplasmic reticulum (ER) and together with inflammation and infection triggers the Unfolded Protein Response (UPR). During the UPR, the Activating Transcription Factor 6 (ATF6) is activated with cleavage and then decreases the expression of p.Phe508del-CFTR. We have previously shown that the inhibition of the activation of ATF6 alleviates the p.Phe508del-CFTR defects in cells overexpressing the mutated protein. In the present paper, our aim was to inhibit the cleavage of ATF6, and thus its activation in a human bronchial cell line with endogenous p.Phe508del-CFTR expression and in bronchial cells from patients, to be more relevant to CF. This was achieved by inhibiting the protease MBTP1 which is responsible for the cleavage of ATF6. We show here that this inhibition leads to increased mRNA and p.Phe508del-CFTR expression and, consequently, to increased Cl-efflux. We also explain the mechanisms linked to these increases with the modulation of genes when MBTP1 is inhibited. Indeed, RT-qPCR assays show that genes such as HSPA1B, CEBPB, VIMP, PFND2, MAPK8, XBP1, INSIG1, and CALR are modulated. In conclusion, we show that the inhibition of MBTP1 has a beneficial effect in relevant models to CF and that this is due to the modulation of genes involved in the disease.
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Affiliation(s)
- Raphaël Santinelli
- Univ Brest, Inserm, EFS, UMR 1078, 22 Avenue Camille Desmoulins, F-29200 Brest, France; (R.S.); (N.B.); (J.G.); (F.Q.); (E.K.); (J.T.); (T.M.); (C.K.); (C.F.)
| | - Nathalie Benz
- Univ Brest, Inserm, EFS, UMR 1078, 22 Avenue Camille Desmoulins, F-29200 Brest, France; (R.S.); (N.B.); (J.G.); (F.Q.); (E.K.); (J.T.); (T.M.); (C.K.); (C.F.)
| | - Julie Guellec
- Univ Brest, Inserm, EFS, UMR 1078, 22 Avenue Camille Desmoulins, F-29200 Brest, France; (R.S.); (N.B.); (J.G.); (F.Q.); (E.K.); (J.T.); (T.M.); (C.K.); (C.F.)
| | - Fabien Quinquis
- Univ Brest, Inserm, EFS, UMR 1078, 22 Avenue Camille Desmoulins, F-29200 Brest, France; (R.S.); (N.B.); (J.G.); (F.Q.); (E.K.); (J.T.); (T.M.); (C.K.); (C.F.)
| | - Ervin Kocas
- Univ Brest, Inserm, EFS, UMR 1078, 22 Avenue Camille Desmoulins, F-29200 Brest, France; (R.S.); (N.B.); (J.G.); (F.Q.); (E.K.); (J.T.); (T.M.); (C.K.); (C.F.)
| | - Johan Thomas
- Univ Brest, Inserm, EFS, UMR 1078, 22 Avenue Camille Desmoulins, F-29200 Brest, France; (R.S.); (N.B.); (J.G.); (F.Q.); (E.K.); (J.T.); (T.M.); (C.K.); (C.F.)
| | - Tristan Montier
- Univ Brest, Inserm, EFS, UMR 1078, 22 Avenue Camille Desmoulins, F-29200 Brest, France; (R.S.); (N.B.); (J.G.); (F.Q.); (E.K.); (J.T.); (T.M.); (C.K.); (C.F.)
| | - Chandran Ka
- Univ Brest, Inserm, EFS, UMR 1078, 22 Avenue Camille Desmoulins, F-29200 Brest, France; (R.S.); (N.B.); (J.G.); (F.Q.); (E.K.); (J.T.); (T.M.); (C.K.); (C.F.)
| | - Emilie Luczka-Majérus
- Inserm UMR-S 1250, University of Reims Champagne-Ardenne (URCA), SFR Cap-Santé, F-51100 Reims, France; (E.L.-M.); (C.C.)
| | - Edouard Sage
- Université Paris-Saclay, INRAE, UVSQ, VIM, F-78350 Jouy-en-Josas, France;
| | - Claude Férec
- Univ Brest, Inserm, EFS, UMR 1078, 22 Avenue Camille Desmoulins, F-29200 Brest, France; (R.S.); (N.B.); (J.G.); (F.Q.); (E.K.); (J.T.); (T.M.); (C.K.); (C.F.)
| | - Christelle Coraux
- Inserm UMR-S 1250, University of Reims Champagne-Ardenne (URCA), SFR Cap-Santé, F-51100 Reims, France; (E.L.-M.); (C.C.)
| | - Pascal Trouvé
- Univ Brest, Inserm, EFS, UMR 1078, 22 Avenue Camille Desmoulins, F-29200 Brest, France; (R.S.); (N.B.); (J.G.); (F.Q.); (E.K.); (J.T.); (T.M.); (C.K.); (C.F.)
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Dang TT, Kim MJ, Lee YY, Le HT, Kim KH, Nam S, Hyun SH, Kim HL, Chung SW, Chung HT, Jho EH, Yoshida H, Kim K, Park CY, Lee MS, Back SH. Phosphorylation of EIF2S1 (eukaryotic translation initiation factor 2 subunit alpha) is indispensable for nuclear translocation of TFEB and TFE3 during ER stress. Autophagy 2023; 19:2111-2142. [PMID: 36719671 PMCID: PMC10283430 DOI: 10.1080/15548627.2023.2173900] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2022] [Revised: 01/21/2023] [Accepted: 01/24/2023] [Indexed: 02/01/2023] Open
Abstract
There are diverse links between macroautophagy/autophagy pathways and unfolded protein response (UPR) pathways under endoplasmic reticulum (ER) stress conditions to restore ER homeostasis. Phosphorylation of EIF2S1/eIF2α is an important mechanism that can regulate all three UPR pathways through transcriptional and translational reprogramming to maintain cellular homeostasis and overcome cellular stresses. In this study, to investigate the roles of EIF2S1 phosphorylation in regulation of autophagy during ER stress, we used EIF2S1 phosphorylation-deficient (A/A) cells in which residue 51 was mutated from serine to alanine. A/A cells exhibited defects in several steps of autophagic processes (such as autophagosome and autolysosome formation) that are regulated by the transcriptional activities of the autophagy master transcription factors TFEB and TFE3 under ER stress conditions. EIF2S1 phosphorylation was required for nuclear translocation of TFEB and TFE3 during ER stress. In addition, EIF2AK3/PERK, PPP3/calcineurin-mediated dephosphorylation of TFEB and TFE3, and YWHA/14-3-3 dissociation were required for their nuclear translocation, but were insufficient to induce their nuclear retention during ER stress. Overexpression of the activated ATF6/ATF6α form, XBP1s, and ATF4 differentially rescued defects of TFEB and TFE3 nuclear translocation in A/A cells during ER stress. Consequently, overexpression of the activated ATF6 or TFEB form more efficiently rescued autophagic defects, although XBP1s and ATF4 also displayed an ability to restore autophagy in A/A cells during ER stress. Our results suggest that EIF2S1 phosphorylation is important for autophagy and UPR pathways, to restore ER homeostasis and reveal how EIF2S1 phosphorylation connects UPR pathways to autophagy.Abbreviations: A/A: EIF2S1 phosphorylation-deficient; ACTB: actin beta; Ad-: adenovirus-; ATF6: activating transcription factor 6; ATZ: SERPINA1/α1-antitrypsin with an E342K (Z) mutation; Baf A1: bafilomycin A1; BSA: bovine serum albumin; CDK4: cyclin dependent kinase 4; CDK6: cyclin dependent kinase 6; CHX: cycloheximide; CLEAR: coordinated lysosomal expression and regulation; Co-IP: coimmunoprecipitation; CTSB: cathepsin B; CTSD: cathepsin D; CTSL: cathepsin L; DAPI: 4',6-diamidino-2-phenylindole dihydrochloride; DMEM: Dulbecco's modified Eagle's medium; DMSO: dimethyl sulfoxide; DTT: dithiothreitol; EBSS: Earle's Balanced Salt Solution; EGFP: enhanced green fluorescent protein; EIF2S1/eIF2α: eukaryotic translation initiation factor 2 subunit alpha; EIF2AK3/PERK: eukaryotic translation initiation factor 2 alpha kinase 3; ER: endoplasmic reticulum; ERAD: endoplasmic reticulum-associated degradation; ERN1/IRE1α: endoplasmic reticulum to nucleus signaling 1; FBS: fetal bovine serum; gRNA: guide RNA; GSK3B/GSK3β: glycogen synthase kinase 3 beta; HA: hemagglutinin; Hep: immortalized hepatocyte; IF: immunofluorescence; IRES: internal ribosome entry site; KO: knockout; LAMP1: lysosomal associated membrane protein 1; LMB: leptomycin B; LPS: lipopolysaccharide; MAP1LC3A/B/LC3A/B: microtubule associated protein 1 light chain 3 alpha/beta; MAP1LC3B/LC3B: microtubule associated protein 1 light chain 3 beta; MEFs: mouse embryonic fibroblasts; MFI: mean fluorescence intensity; MTORC1: mechanistic target of rapamycin kinase complex 1; NES: nuclear export signal; NFE2L2/NRF2: NFE2 like bZIP transcription factor 2; OE: overexpression; PBS: phosphate-buffered saline; PLA: proximity ligation assay; PPP3/calcineurin: protein phosphatase 3; PTM: post-translational modification; SDS: sodium dodecyl sulfate; SDS-PAGE: sodium dodecyl sulfate-polyacrylamide gel electrophoresis; SEM: standard error of the mean; TEM: transmission electron microscopy; TFE3: transcription factor E3; TFEB: transcription factor EB; TFs: transcription factors; Tg: thapsigargin; Tm: tunicamycin; UPR: unfolded protein response; WB: western blot; WT: wild-type; Xbp1s: spliced Xbp1; XPO1/CRM1: exportin 1.
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Affiliation(s)
- Thao Thi Dang
- School of Biological Sciences, University of Ulsan, Ulsan, 44610, Korea
| | - Mi-Jeong Kim
- School of Biological Sciences, University of Ulsan, Ulsan, 44610, Korea
| | - Yoon Young Lee
- Department of Biological Sciences, School of Life Sciences, Ulsan National Institute of Science and Technology, Ulsan, 44919, Korea
| | - Hien Thi Le
- School of Biological Sciences, University of Ulsan, Ulsan, 44610, Korea
| | - Kook Hwan Kim
- Severance Biomedical Research Institute, Yonsei University College of Medicine, 03722, Seoul, Korea
| | - Somi Nam
- School of Biological Sciences, University of Ulsan, Ulsan, 44610, Korea
| | - Seung Hwa Hyun
- School of Biological Sciences, University of Ulsan, Ulsan, 44610, Korea
| | - Hong Lim Kim
- Integrative Research Support Center, College of Medicine, The Catholic University of Korea, Seoul, Korea
| | - Su Wol Chung
- School of Biological Sciences, University of Ulsan, Ulsan, 44610, Korea
| | - Hun Taeg Chung
- School of Biological Sciences, University of Ulsan, Ulsan, 44610, Korea
| | - Eek-Hoon Jho
- Department of Life Science, University of Seoul, Seoul, Korea
| | - Hiderou Yoshida
- Department of Molecular Biochemistry, Graduate School of Life Science, University of Hyogo, 678-1297, Hyogo, Japan
| | - Kyoungmi Kim
- Department of Biomedical Sciences and Department of Physiology, Korea University College of Medicine, 02841, Seoul, Korea
| | - Chan Young Park
- Department of Biological Sciences, School of Life Sciences, Ulsan National Institute of Science and Technology, Ulsan, 44919, Korea
| | - Myung-Shik Lee
- Department of Integrated Biomedical Science & Division of Endocrinology, Department of Internal Medicine, SIMS (Soonchunhyang Institute of Medi-bio Science) & Soonchunhyang University Hospital, Soonchunhyang University, 31151, Cheonan, Korea
| | - Sung Hoon Back
- School of Biological Sciences, University of Ulsan, Ulsan, 44610, Korea
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10
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Sun L, Yang B, Peng Z, Yang T, Qin B, Ao J, Yang Y, Wang J, Zheng L, Xie H. Transcriptomics and Phenotypic Analysis of gpr56 Knockout in Zebrafish. Int J Mol Sci 2023; 24:ijms24097740. [PMID: 37175447 PMCID: PMC10178538 DOI: 10.3390/ijms24097740] [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: 03/29/2023] [Revised: 04/13/2023] [Accepted: 04/19/2023] [Indexed: 05/15/2023] Open
Abstract
The adhesion G-protein-coupled receptor is a seven-transmembrane receptor protein with a complex structure. Impaired GPR56 has been found to cause developmental damage to the human brain, resulting in intellectual disability and motor dysfunction. To date, studies on gpr56 deficiency in zebrafish have been limited to the nervous system, and there have been no reports of its systemic effects on juvenile fish at developmental stages. In order to explore the function of gpr56 in zebrafish, the CRISPR/Cas9 gene-editing system was used to construct a gpr56-knockout zebrafish. Subsequently, the differentially expressed genes (DEGs) at the transcriptional level between the 3 days post fertilization (dpf) homozygotes of the gpr56 mutation and the wildtype zebrafish were analyzed via RNA-seq. The results of the clustering analysis, quantitative PCR (qPCR), and in situ hybridization demonstrated that the expression of innate immunity-related genes in the mutant was disordered, and multiple genes encoding digestive enzymes of the pancreatic exocrine glands were significantly downregulated in the mutant. Motor ability tests demonstrated that the gpr56-/- zebrafish were more active, and this change was more pronounced in the presence of cold and additional stimuli. In conclusion, our results revealed the effect of gpr56 deletion on the gene expression of juvenile zebrafish and found that the gpr56 mutant was extremely active, providing an important clue for studying the mechanism of gpr56 in the development of juvenile zebrafish.
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Affiliation(s)
- Luning Sun
- Hunan International Joint Laboratory of Animal Intestinal Ecology and Health, Laboratory of Animal Nutrition and Human Health, College of Life Sciences, Hunan Normal University, Changsha 410081, China
- Hunan Provincial Key Laboratory of Animal Intestinal Function and Regulation, Changsha 410081, China
| | - Boyu Yang
- Key Laboratory of Physical Fitness and Exercise Rehabilitation of Hunan Province, Hunan Normal University, Changsha 410081, China
| | - Zheng Peng
- Key Laboratory of Physical Fitness and Exercise Rehabilitation of Hunan Province, Hunan Normal University, Changsha 410081, China
| | - Tianle Yang
- Key Laboratory of Physical Fitness and Exercise Rehabilitation of Hunan Province, Hunan Normal University, Changsha 410081, China
| | - Bin Qin
- Heart Development Center, College of Life Science, Hunan Normal University, Changsha 410081, China
| | - Jieyu Ao
- Heart Development Center, College of Life Science, Hunan Normal University, Changsha 410081, China
| | - Yanqun Yang
- Hunan International Joint Laboratory of Animal Intestinal Ecology and Health, Laboratory of Animal Nutrition and Human Health, College of Life Sciences, Hunan Normal University, Changsha 410081, China
- Hunan Provincial Key Laboratory of Animal Intestinal Function and Regulation, Changsha 410081, China
| | - Jingling Wang
- Hunan International Joint Laboratory of Animal Intestinal Ecology and Health, Laboratory of Animal Nutrition and Human Health, College of Life Sciences, Hunan Normal University, Changsha 410081, China
- Hunan Provincial Key Laboratory of Animal Intestinal Function and Regulation, Changsha 410081, China
| | - Lan Zheng
- Key Laboratory of Physical Fitness and Exercise Rehabilitation of Hunan Province, Hunan Normal University, Changsha 410081, China
| | - Huaping Xie
- Hunan International Joint Laboratory of Animal Intestinal Ecology and Health, Laboratory of Animal Nutrition and Human Health, College of Life Sciences, Hunan Normal University, Changsha 410081, China
- Hunan Provincial Key Laboratory of Animal Intestinal Function and Regulation, Changsha 410081, China
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11
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Alzahrani MR, Guan BJ, Zagore LL, Wu J, Chen CW, Licatalosi DD, Baker KE, Hatzoglou M. Newly synthesized mRNA escapes translational repression during the acute phase of the mammalian unfolded protein response. PLoS One 2022; 17:e0271695. [PMID: 35947624 PMCID: PMC9365188 DOI: 10.1371/journal.pone.0271695] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2022] [Accepted: 07/06/2022] [Indexed: 11/19/2022] Open
Abstract
Endoplasmic Reticulum (ER) stress, caused by the accumulation of misfolded proteins in the ER, elicits a homeostatic mechanism known as the Unfolded Protein Response (UPR). The UPR reprograms gene expression to promote adaptation to chronic ER stress. The UPR comprises an acute phase involving inhibition of bulk protein synthesis and a chronic phase of transcriptional induction coupled with the partial recovery of protein synthesis. However, the role of transcriptional regulation in the acute phase of the UPR is not well understood. Here we analyzed the fate of newly synthesized mRNA encoding the protective and homeostatic transcription factor X-box binding protein 1 (XBP1) during this acute phase. We have previously shown that global translational repression induced by the acute UPR was characterized by decreased translation and increased stability of XBP1 mRNA. We demonstrate here that this stabilization is independent of new transcription. In contrast, we show XBP1 mRNA newly synthesized during the acute phase accumulates with long poly(A) tails and escapes translational repression. Inhibition of newly synthesized RNA polyadenylation during the acute phase decreased cell survival with no effect in unstressed cells. Furthermore, during the chronic phase of the UPR, levels of XBP1 mRNA with long poly(A) tails decreased in a manner consistent with co-translational deadenylation. Finally, additional pro-survival, transcriptionally-induced mRNAs show similar regulation, supporting the broad significance of the pre-steady state UPR in translational control during ER stress. We conclude that the biphasic regulation of poly(A) tail length during the UPR represents a previously unrecognized pro-survival mechanism of mammalian gene regulation.
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Affiliation(s)
- Mohammed R. Alzahrani
- Department of Biochemistry, Case Western Reserve University, Cleveland, Ohio, United States of America
| | - Bo-Jhih Guan
- Department of Genetics and Genome Sciences, Case Western Reserve University, Cleveland, Ohio, United States of America
| | - Leah L. Zagore
- Department of Biochemistry, Case Western Reserve University, Cleveland, Ohio, United States of America
- Center for RNA Science and Therapeutics, Case Western Reserve University, Cleveland, Ohio, United States of America
| | - Jing Wu
- Department of Genetics and Genome Sciences, Case Western Reserve University, Cleveland, Ohio, United States of America
| | - Chien-Wen Chen
- Department of Biochemistry, Case Western Reserve University, Cleveland, Ohio, United States of America
| | - Donny D. Licatalosi
- Department of Biochemistry, Case Western Reserve University, Cleveland, Ohio, United States of America
- Center for RNA Science and Therapeutics, Case Western Reserve University, Cleveland, Ohio, United States of America
| | - Kristian E. Baker
- Department of Genetics and Genome Sciences, Case Western Reserve University, Cleveland, Ohio, United States of America
| | - Maria Hatzoglou
- Department of Genetics and Genome Sciences, Case Western Reserve University, Cleveland, Ohio, United States of America
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12
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Cairrão F, Santos CC, Le Thomas A, Marsters S, Ashkenazi A, Domingos PM. Pumilio protects Xbp1 mRNA from regulated Ire1-dependent decay. Nat Commun 2022; 13:1587. [PMID: 35332141 PMCID: PMC8948244 DOI: 10.1038/s41467-022-29105-x] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2021] [Accepted: 02/17/2022] [Indexed: 12/12/2022] Open
Abstract
The unfolded protein response (UPR) maintains homeostasis of the endoplasmic reticulum (ER). Residing in the ER membrane, the UPR mediator Ire1 deploys its cytoplasmic kinase-endoribonuclease domain to activate the key UPR transcription factor Xbp1 through non-conventional splicing of Xbp1 mRNA. Ire1 also degrades diverse ER-targeted mRNAs through regulated Ire1-dependent decay (RIDD), but how it spares Xbp1 mRNA from this decay is unknown. Here, we identify binding sites for the RNA-binding protein Pumilio in the 3'UTR Drosophila Xbp1. In the developing Drosophila eye, Pumilio binds both the Xbp1unspliced and Xbp1spliced mRNAs, but only Xbp1spliced is stabilized by Pumilio. Furthermore, Pumilio displays Ire1 kinase-dependent phosphorylation during ER stress, which is required for its stabilization of Xbp1spliced. hIRE1 can phosphorylate Pumilio directly, and phosphorylated Pumilio protects Xbp1spliced mRNA against RIDD. Thus, Ire1-mediated phosphorylation enables Pumilio to shield Xbp1spliced from RIDD. These results uncover an unexpected regulatory link between an RNA-binding protein and the UPR.
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Affiliation(s)
- Fátima Cairrão
- Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Av. da República, 2780-157, Oeiras, Portugal.
| | - Cristiana C Santos
- Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Av. da República, 2780-157, Oeiras, Portugal
| | - Adrien Le Thomas
- Cancer Immunology, Genentech, Inc., 1 DNA Way, South San Francisco, CA, 94080, USA
| | - Scot Marsters
- Cancer Immunology, Genentech, Inc., 1 DNA Way, South San Francisco, CA, 94080, USA
| | - Avi Ashkenazi
- Cancer Immunology, Genentech, Inc., 1 DNA Way, South San Francisco, CA, 94080, USA
| | - Pedro M Domingos
- Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Av. da República, 2780-157, Oeiras, Portugal.
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13
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Gebert M, Sobolewska A, Bartoszewska S, Cabaj A, Crossman DK, Króliczewski J, Madanecki P, Dąbrowski M, Collawn JF, Bartoszewski R. Genome-wide mRNA profiling identifies X-box-binding protein 1 (XBP1) as an IRE1 and PUMA repressor. Cell Mol Life Sci 2021; 78:7061-7080. [PMID: 34636989 PMCID: PMC8558229 DOI: 10.1007/s00018-021-03952-1] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2021] [Revised: 09/17/2021] [Accepted: 09/28/2021] [Indexed: 02/06/2023]
Abstract
Accumulation of misfolded proteins in ER activates the unfolded protein response (UPR), a multifunctional signaling pathway that is important for cell survival. The UPR is regulated by three ER transmembrane sensors, one of which is inositol-requiring protein 1 (IRE1). IRE1 activates a transcription factor, X-box-binding protein 1 (XBP1), by removing a 26-base intron from XBP1 mRNA that generates spliced XBP1 mRNA (XBP1s). To search for XBP1 transcriptional targets, we utilized an XBP1s-inducible human cell line to limit XBP1 expression in a controlled manner. We also verified the identified XBP1-dependent genes with specific silencing of this transcription factor during pharmacological ER stress induction with both an N-linked glycosylation inhibitor (tunicamycin) and a non-competitive inhibitor of the sarco/endoplasmic reticulum Ca2+ ATPase (SERCA) (thapsigargin). We then compared those results to the XBP1s-induced cell line without pharmacological ER stress induction. Using next‐generation sequencing followed by bioinformatic analysis of XBP1-binding motifs, we defined an XBP1 regulatory network and identified XBP1 as a repressor of PUMA (a proapoptotic gene) and IRE1 mRNA expression during the UPR. Our results indicate impairing IRE1 activity during ER stress conditions accelerates cell death in ER-stressed cells, whereas elevating XBP1 expression during ER stress using an inducible cell line correlated with a clear prosurvival effect and reduced PUMA protein expression. Although further studies will be required to test the underlying molecular mechanisms involved in the relationship between these genes with XBP1, these studies identify a novel repressive role of XBP1 during the UPR.
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Affiliation(s)
- Magdalena Gebert
- Department of Biology and Pharmaceutical Botany, Medical University of Gdansk, Hallera 107, 80-416, Gdansk, Poland
| | - Aleksandra Sobolewska
- Department of Biology and Pharmaceutical Botany, Medical University of Gdansk, Hallera 107, 80-416, Gdansk, Poland
| | - Sylwia Bartoszewska
- Department of Inorganic Chemistry, Medical University of Gdansk, Gdansk, Poland
| | - Aleksandra Cabaj
- Laboratory of Bioinformatics, Nencki Institute of Experimental Biology of the Polish Academy of Sciences, Warsaw, Poland
| | - David K Crossman
- Department of Genetics, Heflin Center for Genomic Science, University of Alabama at Birmingham, Birmingham, AL, 35233, USA
| | - Jarosław Króliczewski
- Department of Biology and Pharmaceutical Botany, Medical University of Gdansk, Hallera 107, 80-416, Gdansk, Poland
| | - Piotr Madanecki
- Department of Biology and Pharmaceutical Botany, Medical University of Gdansk, Hallera 107, 80-416, Gdansk, Poland
| | - Michał Dąbrowski
- Laboratory of Bioinformatics, Nencki Institute of Experimental Biology of the Polish Academy of Sciences, Warsaw, Poland
| | - James F Collawn
- Department of Cell, Developmental and Integrative Biology, University of Alabama at Birmingham, Birmingham, AL, 35233, USA
| | - Rafal Bartoszewski
- Department of Biology and Pharmaceutical Botany, Medical University of Gdansk, Hallera 107, 80-416, Gdansk, Poland.
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14
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Ricci D, Gidalevitz T, Argon Y. The special unfolded protein response in plasma cells. Immunol Rev 2021; 303:35-51. [PMID: 34368957 DOI: 10.1111/imr.13012] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2021] [Accepted: 06/08/2021] [Indexed: 12/11/2022]
Abstract
The high rate of antibody production places considerable metabolic and folding stress on plasma cells (PC). Not surprisingly, they rely on the unfolded protein response (UPR), a universal signaling, and transcriptional network that monitors the health of the secretory pathway and mounts cellular responses to stress. Typically, the UPR utilizes three distinct stress sensors in the ER membrane, each regulating a subset of targets to re-establish homeostasis. PC use a specialized UPR scheme-they preemptively trigger the UPR via developmental signals and suppress two of the sensors, PERK and ATF6, relying on IRE1 alone. The specialized PC UPR program is tuned to the specific needs at every stage of development-from early biogenesis of secretory apparatus, to massive immunoglobulin expression later. Furthermore, the UPR in PC integrates with other pathways essential in a highly secretory cell-mTOR pathway that ensures efficient synthesis, autophagosomes that recycle components of the synthetic machinery, and apoptotic signaling that controls cell fate in the face of excessive folding stress. This specialized PC program is not shared with other secretory cells, for reasons yet to be defined. In this review, we give a perspective into how and why PC need such a unique UPR program.
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Affiliation(s)
- Daniela Ricci
- Department of Pathology and Lab Medicine, The Childrens' Hospital of Philadelphia and the University of Pennsylvania, Philadelphia, PA, USA
| | - Tali Gidalevitz
- Department of Biology, Drexel University, Philadelphia, PA, USA
| | - Yair Argon
- Department of Pathology and Lab Medicine, The Childrens' Hospital of Philadelphia and the University of Pennsylvania, Philadelphia, PA, USA
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15
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Eremin DV, Ilchibaeva TV, Tsybko AS. Cerebral Dopamine Neurotrophic Factor (CDNF): Structure, Functions, and Therapeutic Potential. BIOCHEMISTRY (MOSCOW) 2021; 86:852-866. [PMID: 34284712 DOI: 10.1134/s0006297921070063] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
The cerebral dopamine neurotrophic factor (CDNF) together with the mesencephalic astrocyte-derived neurotrophic factor (MANF) form a unique family of neurotrophic factors (NTFs) structurally and functionally different from other proteins with neurotrophic activity. CDNF has no receptors on the cell membrane, is localized mainly in the cavity of endoplasmic reticulum (ER), and its primary function is to regulate ER stress. In addition, CDNF is able to suppress inflammation and apoptosis. Due to its functions, CDNF has demonstrated outstanding protective and restorative properties in various models of neuropathology associated with ER stress, including Parkinson's disease (PD). That is why CDNF already passed clinical trials in patients with PD. However, despite the name, CDNF functions extend far beyond the dopamine system in the brain. In particular, there are data on participation of CDNF in the maturation and maintenance of other neurotransmitter systems, regulation of the processes of neuroplasticity and non-motor behavior. In the present review, we discuss the features of CDNF structure and functions, its protective and regenerative properties.
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Affiliation(s)
- Dmitry V Eremin
- Institute of Cytology and Genetics, Siberian Branch of the Russian Academy of Sciences, Novosibirsk, 630090, Russia
| | - Tatiana V Ilchibaeva
- Institute of Cytology and Genetics, Siberian Branch of the Russian Academy of Sciences, Novosibirsk, 630090, Russia
| | - Anton S Tsybko
- Institute of Cytology and Genetics, Siberian Branch of the Russian Academy of Sciences, Novosibirsk, 630090, Russia.
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16
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Smedley GD, Walker KE, Yuan SH. The Role of PERK in Understanding Development of Neurodegenerative Diseases. Int J Mol Sci 2021; 22:ijms22158146. [PMID: 34360909 PMCID: PMC8348817 DOI: 10.3390/ijms22158146] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2021] [Revised: 07/26/2021] [Accepted: 07/28/2021] [Indexed: 01/01/2023] Open
Abstract
Neurodegenerative diseases are an ever-increasing problem for the rapidly aging population. Despite this, our understanding of how these neurodegenerative diseases develop and progress, is in most cases, rudimentary. Protein kinase RNA (PKR)-like ER kinase (PERK) comprises one of three unfolded protein response pathways in which cells attempt to manage cellular stress. However, because of its role in the cellular stress response and the far-reaching implications of this pathway, error within the PERK pathway has been shown to lead to a variety of pathologies. Genetic and clinical studies show a correlation between failure of the PERK pathway in neural cells and the development of neurodegeneration, but the wide array of methodology of these studies is presenting conflicting narratives about the role of PERK in these affected systems. Because of the connection between PERK and pathology, PERK has become a high value target of study for understanding neurodegenerative diseases and potentially how to treat them. Here, we present a review of the literature indexed in PubMed of the PERK pathway and some of the complexities involved in investigating the protein's role in the development of neurodegenerative diseases as well as how it may act as a target for therapeutics.
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Affiliation(s)
- Garrett Dalton Smedley
- Department of Neurology, University of Minnesota, Twin Cities, Minneapolis, MN 55455, USA; (G.D.S.); (K.E.W.)
| | - Keenan E. Walker
- Department of Neurology, University of Minnesota, Twin Cities, Minneapolis, MN 55455, USA; (G.D.S.); (K.E.W.)
| | - Shauna H. Yuan
- Department of Neurology, University of Minnesota, Twin Cities, Minneapolis, MN 55455, USA; (G.D.S.); (K.E.W.)
- GRECC, Minneapolis VA Health Care System, Minneapolis, MN 55417, USA
- Correspondence:
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17
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Popovic R, Celardo I, Yu Y, Costa AC, Loh SHY, Martins LM. Combined Transcriptomic and Proteomic Analysis of Perk Toxicity Pathways. Int J Mol Sci 2021; 22:4598. [PMID: 33925631 PMCID: PMC8124185 DOI: 10.3390/ijms22094598] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2021] [Revised: 04/19/2021] [Accepted: 04/23/2021] [Indexed: 12/17/2022] Open
Abstract
In Drosophila, endoplasmic reticulum (ER) stress activates the protein kinase R-like endoplasmic reticulum kinase (dPerk). dPerk can also be activated by defective mitochondria in fly models of Parkinson's disease caused by mutations in pink1 or parkin. The Perk branch of the unfolded protein response (UPR) has emerged as a major toxic process in neurodegenerative disorders causing a chronic reduction in vital proteins and neuronal death. In this study, we combined microarray analysis and quantitative proteomics analysis in adult flies overexpressing dPerk to investigate the relationship between the transcriptional and translational response to dPerk activation. We identified tribbles and Heat shock protein 22 as two novel Drosophila activating transcription factor 4 (dAtf4) regulated transcripts. Using a combined bioinformatics tool kit, we demonstrated that the activation of dPerk leads to translational repression of mitochondrial proteins associated with glutathione and nucleotide metabolism, calcium signalling and iron-sulphur cluster biosynthesis. Further efforts to enhance these translationally repressed dPerk targets might offer protection against Perk toxicity.
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Affiliation(s)
| | | | | | | | | | - L. Miguel Martins
- MRC Toxicology Unit, University of Cambridge, Gleeson Building, Tennis Court Road, Cambridge CB2 1QR, UK; (R.P.); (I.C.); (Y.Y.); (A.C.C.); (S.H.Y.L.)
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18
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Efimova I, Steinberg I, Zvibel I, Neumann A, Mantelmacher DF, Drucker DJ, Fishman S, Varol C. GIPR Signaling in Immune Cells Maintains Metabolically Beneficial Type 2 Immune Responses in the White Fat From Obese Mice. Front Immunol 2021; 12:643144. [PMID: 33717200 PMCID: PMC7947693 DOI: 10.3389/fimmu.2021.643144] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2020] [Accepted: 01/14/2021] [Indexed: 02/06/2023] Open
Abstract
Glucose-dependent insulinotropic polypeptide (GIP) communicates information on energy availability from the gut to peripheral tissues. Disruption of its signaling in myeloid immune cells during high-fat diet (HFD)-induced obesity impairs energy homeostasis due to the unrestrained metabolically deleterious actions of S100A8/A9 alarmin. White adipose tissue (WAT) type 2 immune cell networks are important for maintaining metabolic and energy homeostasis and limiting obesity-induced inflammation. Nevertheless, the consequences of losing immune cell GIP receptor (GIPR) signaling on type 2 immunity in WAT remains unknown. Bone marrow (BM) chimerism was used to generate mice with GIPR (Gipr-/- BM) and GIPR/S100A8/A9 (Gipr-/- /S100a9-/- BM) deletion in immune cells. These mice were subjected to short (5 weeks) and progressive (14 weeks) HFD regimens. GIPR-deficiency was also targeted to myeloid cells by crossing Giprfl/fl mice and Lyz2cre/+ mice (LysMΔGipr ). Under both short and progressive HFD regimens, Gipr-/- BM mice exhibited altered expression of key type 2 immune cytokines in the epididymal visceral WAT (epiWAT), but not in subcutaneous inguinal WAT. This was further linked to declined representation of type 2 immune cells in epiWAT, such as group 2 innate lymphoid cells (ILC2), eosinophils, and FOXP3+ regulatory T cells (Tregs). Co-deletion of S100A8/A9 in Gipr-/- immune cells reversed the impairment of type 2 cytokine expression in epiWAT, suggesting a mechanistic role for this alarmin in type 2 immune suppression. LysMΔGipr mice on HFD also displayed altered expression of type 2 immune mediators, highlighting that GIPR-deficiency in myeloid immune cells is responsible for the impairment of type 2 immune networks. Finally, abrogated GIPR signaling in immune cells also affected adipocyte fraction cells, inducing their increased production of the beiging interfering cytokine IL-10 and stress- related type 2 cytokine IL-13. Collectively, these findings attribute an important role for GIPR in myeloid immune cells in supporting WAT type 2 immunity.
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Affiliation(s)
- Irina Efimova
- The Research Center for Digestive Tract and Liver Diseases, Tel-Aviv Sourasky Medical Center Affiliated to Tel-Aviv University, Tel Aviv, Israel.,Department of Clinical Microbiology and Immunology, Sackler School of Medicine, Tel-Aviv University, Tel-Aviv, Israel
| | - Inbar Steinberg
- The Research Center for Digestive Tract and Liver Diseases, Tel-Aviv Sourasky Medical Center Affiliated to Tel-Aviv University, Tel Aviv, Israel.,Department of Clinical Microbiology and Immunology, Sackler School of Medicine, Tel-Aviv University, Tel-Aviv, Israel
| | - Isabel Zvibel
- The Research Center for Digestive Tract and Liver Diseases, Tel-Aviv Sourasky Medical Center Affiliated to Tel-Aviv University, Tel Aviv, Israel
| | - Anat Neumann
- The Research Center for Digestive Tract and Liver Diseases, Tel-Aviv Sourasky Medical Center Affiliated to Tel-Aviv University, Tel Aviv, Israel.,Department of Clinical Microbiology and Immunology, Sackler School of Medicine, Tel-Aviv University, Tel-Aviv, Israel
| | - Dana Fernanda Mantelmacher
- The Research Center for Digestive Tract and Liver Diseases, Tel-Aviv Sourasky Medical Center Affiliated to Tel-Aviv University, Tel Aviv, Israel
| | - Daniel J Drucker
- The Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, University of Toronto, Toronto, ON, Canada
| | - Sigal Fishman
- The Research Center for Digestive Tract and Liver Diseases, Tel-Aviv Sourasky Medical Center Affiliated to Tel-Aviv University, Tel Aviv, Israel
| | - Chen Varol
- The Research Center for Digestive Tract and Liver Diseases, Tel-Aviv Sourasky Medical Center Affiliated to Tel-Aviv University, Tel Aviv, Israel.,Department of Clinical Microbiology and Immunology, Sackler School of Medicine, Tel-Aviv University, Tel-Aviv, Israel
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19
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Revealing the hidden reality of the mammalian 12-h ultradian rhythms. Cell Mol Life Sci 2021; 78:3127-3140. [PMID: 33449146 DOI: 10.1007/s00018-020-03730-5] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2020] [Revised: 11/18/2020] [Accepted: 12/04/2020] [Indexed: 12/29/2022]
Abstract
Biological oscillations often cycle at different harmonics of the 24-h circadian rhythms, a phenomenon we coined "Musica Universalis" in 2017. Like the circadian rhythm, the 12-h oscillation is also evolutionarily conserved, robust, and has recently gained new traction in the field of chronobiology. Originally thought to be regulated by the circadian clock and/or environmental cues, recent new evidences support the notion that the majority of 12-h rhythms are regulated by a distinct and cell-autonomous pacemaker that includes the unfolded protein response (UPR) transcription factor spliced form of XBP1 (XBP1s). 12-h cycle of XBP1s level in turn transcriptionally generates robust 12-h rhythms of gene expression enriched in the central dogma information flow (CEDIF) pathway. Given the regulatory and functional separation of the 12-h and circadian clocks, in this review, we will focus our attention on the mammalian 12-h pacemaker, and discuss our current understanding of its prevalence, evolutionary origin, regulation, and functional roles in both physiological and pathological processes.
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20
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Guerrina N, Aloufi N, Shi F, Prasade K, Mehrotra C, Traboulsi H, Matthews J, Eidelman DH, Hamid Q, Baglole CJ. The aryl hydrocarbon receptor reduces LC3II expression and controls endoplasmic reticulum stress. Am J Physiol Lung Cell Mol Physiol 2020; 320:L339-L355. [PMID: 33236922 DOI: 10.1152/ajplung.00122.2020] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
The aryl hydrocarbon receptor (AhR) is a ligand-activated transcription factor whose physiological function is poorly understood. The AhR is highly expressed in barrier organs such as the skin, intestine, and lung. The lungs are continuously exposed to environmental pollutants such as cigarette smoke (CS) that can induce cell death mechanisms such as apoptosis, autophagy, and endoplasmic reticulum (ER) stress. CS also contains toxicants that are AhR ligands. We have previously shown that the AhR protects against apoptosis, but whether the AhR also protects against autophagy or ER stress is not known. Using cigarette smoke extract (CSE) as our in vitro surrogate of environmental tobacco exposure, we first assessed the conversion of LC3I to LC3II, a classic feature of both autophagic and ER stress-mediated cell death pathways. LC3II was elevated in CSE-exposed lung structural cells [mouse lung fibroblasts (MLFs), MLE12 and A549 cells] when AhR was absent. However, this heightened LC3II expression could not be explained by increased expression of key autophagy genes (Gabarapl1, Becn1, Map1lc3b), upregulation of upstream autophagic machinery (Atg5-12, Atg3), or impaired autophagic flux, suggesting that LC3II may be autophagy independent. This was further supported by the absence of autophagosomes in Ahr-/- lung cells. However, Ahr-/- lung cells had widespread ER dilation, elevated expression of the ER stress markers CHOP and GADD34, and an accumulation of ubiquitinated proteins. These findings collectively illustrate a novel role for the AhR in attenuating ER stress by a mechanism that may be autophagy independent.
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Affiliation(s)
- Necola Guerrina
- Research Institute of the McGill University Health Centre, McGill University, Montreal, Quebec, Canada.,Department of Pathology, McGill University, Montreal, Quebec, Canada
| | - Noof Aloufi
- Research Institute of the McGill University Health Centre, McGill University, Montreal, Quebec, Canada.,Department of Pathology, McGill University, Montreal, Quebec, Canada
| | - Fangyi Shi
- Research Institute of the McGill University Health Centre, McGill University, Montreal, Quebec, Canada.,Department of Pathology, McGill University, Montreal, Quebec, Canada
| | - Kashmira Prasade
- Research Institute of the McGill University Health Centre, McGill University, Montreal, Quebec, Canada
| | - Caitlin Mehrotra
- Department of Pharmacology and Therapeutics, McGill University, Montreal, Quebec, Canada
| | - Hussein Traboulsi
- Research Institute of the McGill University Health Centre, McGill University, Montreal, Quebec, Canada.,Department of Medicine, McGill University, Montreal, Quebec, Canada
| | - Jason Matthews
- Department of Nutrition, University of Oslo, Oslo, Norway.,Department of Pharmacology and Toxicology, University of Toronto, Toronto, Ontario, Canada
| | - David H Eidelman
- Research Institute of the McGill University Health Centre, McGill University, Montreal, Quebec, Canada.,Department of Medicine, McGill University, Montreal, Quebec, Canada
| | - Qutayba Hamid
- Research Institute of the McGill University Health Centre, McGill University, Montreal, Quebec, Canada.,Department of Medicine, McGill University, Montreal, Quebec, Canada.,College of Medicine, University of Sharjah, Sharjah, United Arab Emirates
| | - Carolyn J Baglole
- Research Institute of the McGill University Health Centre, McGill University, Montreal, Quebec, Canada.,Department of Pathology, McGill University, Montreal, Quebec, Canada.,Department of Medicine, McGill University, Montreal, Quebec, Canada.,Department of Pharmacology and Therapeutics, McGill University, Montreal, Quebec, Canada
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21
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Bashir S, Banday M, Qadri O, Bashir A, Hilal N, Nida-I-Fatima, Rader S, Fazili KM. The molecular mechanism and functional diversity of UPR signaling sensor IRE1. Life Sci 2020; 265:118740. [PMID: 33188833 DOI: 10.1016/j.lfs.2020.118740] [Citation(s) in RCA: 51] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2020] [Revised: 11/03/2020] [Accepted: 11/06/2020] [Indexed: 02/06/2023]
Abstract
The endoplasmic reticulum is primarily responsible for protein folding and maturation. However, the organelle is subject to varied stress conditions from time to time, which lead to the activation of a signaling program known as the Unfolded Protein Response (UPR) pathway. This pathway, upon sensing any disturbance in the protein-folding milieu sends signals to the nucleus and cytoplasm in order to restore homeostasis. One of the prime UPR signaling sensors is Inositol-requiring enzyme 1 (IRE1); an ER membrane embedded protein with dual enzyme activities, kinase and endoribonuclease. The ribonuclease activity of IRE1 results in Xbp1 splicing in mammals or Hac1 splicing in yeast. However, IRE1 can switch its substrate specificity to the mRNAs that are co-transnationally transported to the ER, a phenomenon known as Regulated IRE1 Dependent Decay (RIDD). IRE1 is also reported to act as a principal molecule that coordinates with other proteins and signaling pathways, which in turn might be responsible for its regulation. The current review highlights studies on IRE1 explaining the structural features and molecular mechanism behind its ribonuclease outputs. The emphasis is also laid on the molecular effectors, which directly or indirectly interact with IRE1 to either modulate its function or connect it to other pathways. This is important in understanding the functional pleiotropy of IRE1, by which it can switch its activity from pro-survival to pro-apoptotic, thus determining the fate of cells.
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Affiliation(s)
- Samirul Bashir
- Department of Biotechnology, University of Kashmir, Srinagar, Jammu and Kashmir, India
| | - Mariam Banday
- Department of Biotechnology, University of Kashmir, Srinagar, Jammu and Kashmir, India
| | - Ozaira Qadri
- Department of Biotechnology, University of Kashmir, Srinagar, Jammu and Kashmir, India
| | - Arif Bashir
- Department of Biotechnology, University of Kashmir, Srinagar, Jammu and Kashmir, India
| | - Nazia Hilal
- Department of Biotechnology, University of Kashmir, Srinagar, Jammu and Kashmir, India
| | - Nida-I-Fatima
- Department of Biotechnology, University of Kashmir, Srinagar, Jammu and Kashmir, India
| | - Stephen Rader
- Department of Chemistry, University of Northern British Columbia, Prince George, BC, Canada
| | - Khalid Majid Fazili
- Department of Biotechnology, University of Kashmir, Srinagar, Jammu and Kashmir, India.
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22
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Chen X, Li H, Fan X, Zhao C, Ye K, Zhao Z, Hu L, Ma H, Wang H, Fang Z. Protein Palmitoylation Regulates Cell Survival by Modulating XBP1 Activity in Glioblastoma Multiforme. MOLECULAR THERAPY-ONCOLYTICS 2020; 17:518-530. [PMID: 33024813 PMCID: PMC7525067 DOI: 10.1016/j.omto.2020.05.007] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/12/2020] [Accepted: 05/20/2020] [Indexed: 01/22/2023]
Abstract
Glioblastoma multiforme (GBM) almost invariably acquires an invasive phenotype, resulting in limited therapeutic options. Protein palmitoylation markedly affects tumorigenesis and malignant progression in GBM. The role of protein palmitoylation in GBM, however, has not been systematically reported. This study aimed to investigate the effect of protein palmitoylation on GBM cell survival and the cell cycle. In this study, most palmitoyltransferases were upregulated in GBM and its cell lines, and protein palmitoylation participated in signaling pathways controlling cell survival and the GBM cell cycle. Inhibition of protein palmitoylation with substrate-analog inhibitors, that is, 2-bromopalmitate, cerulenin, and tunicamycin, induced G2 cell cycle arrest and cell death in GBM cells through enhanced endoplasmic reticulum (ER) stress. These effects are primarily attributed to the palmitoylation inhibitors activating pro-apoptotic pathways and ER stress signals. Further analysis revealed was the accumulation of SUMOylated XBP1 (X-box binding protein 1) and its transcriptional repression, along with a reduction in XBP1 palmitoylation. Taken together, the present results indicate that protein palmitoylation plays an important role in the survival of GBM cells, further providing a potential therapeutic strategy for GBM.
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Affiliation(s)
- Xueran Chen
- Anhui Province Key Laboratory of Medical Physics and Technology, Center of Medical Physics and Technology, Hefei Institutes of Physical Science, Chinese Academy of Sciences, No. 350, Shushan Hu Road, Hefei, Anhui 230031, China
- Department of Molecular Pathology, Hefei Cancer Hospital, Chinese Academy of Sciences, No. 350, ShuShan Hu Road, Hefei, Anhui 230031, China
- Corresponding author: Xueran Chen, Anhui Province Key Laboratory of Medical Physics and Technology, Center of Medical Physics and Technology, Hefei Institutes of Physical Science, Chinese Academy of Sciences, No. 350, Shushan Hu Road, Hefei, Anhui 230031, China.
| | - Hao Li
- School of Life Sciences, University of Science and Technology of China, No. 96, JinZhai Road, Hefei, Anhui 230026, China
| | - Xiaoqing Fan
- The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China (USTC), No. 17, Lujiang Road, Hefei, Anhui 230001, China
- Department of Anesthesiology, Anhui Provincial Hospital, No. 17, Lujiang Road, Hefei, Anhui 230001, China
| | - Chenggang Zhao
- Anhui Province Key Laboratory of Medical Physics and Technology, Center of Medical Physics and Technology, Hefei Institutes of Physical Science, Chinese Academy of Sciences, No. 350, Shushan Hu Road, Hefei, Anhui 230031, China
- School of Life Sciences, University of Science and Technology of China, No. 96, JinZhai Road, Hefei, Anhui 230026, China
| | - Kaiqin Ye
- Anhui Province Key Laboratory of Medical Physics and Technology, Center of Medical Physics and Technology, Hefei Institutes of Physical Science, Chinese Academy of Sciences, No. 350, Shushan Hu Road, Hefei, Anhui 230031, China
- Department of Molecular Pathology, Hefei Cancer Hospital, Chinese Academy of Sciences, No. 350, ShuShan Hu Road, Hefei, Anhui 230031, China
| | - Zhiyang Zhao
- Anhui Province Key Laboratory of Medical Physics and Technology, Center of Medical Physics and Technology, Hefei Institutes of Physical Science, Chinese Academy of Sciences, No. 350, Shushan Hu Road, Hefei, Anhui 230031, China
- School of Life Sciences, University of Science and Technology of China, No. 96, JinZhai Road, Hefei, Anhui 230026, China
| | - Lizhu Hu
- Anhui Province Key Laboratory of Medical Physics and Technology, Center of Medical Physics and Technology, Hefei Institutes of Physical Science, Chinese Academy of Sciences, No. 350, Shushan Hu Road, Hefei, Anhui 230031, China
- School of Life Sciences, University of Science and Technology of China, No. 96, JinZhai Road, Hefei, Anhui 230026, China
| | - Huihui Ma
- Department of Radiation Oncology, First Affiliated Hospital, Anhui Medical University, No. 218, JiXi Road, Hefei, Anhui 230031, China
| | - Hongzhi Wang
- Anhui Province Key Laboratory of Medical Physics and Technology, Center of Medical Physics and Technology, Hefei Institutes of Physical Science, Chinese Academy of Sciences, No. 350, Shushan Hu Road, Hefei, Anhui 230031, China
- Department of Molecular Pathology, Hefei Cancer Hospital, Chinese Academy of Sciences, No. 350, ShuShan Hu Road, Hefei, Anhui 230031, China
| | - Zhiyou Fang
- Anhui Province Key Laboratory of Medical Physics and Technology, Center of Medical Physics and Technology, Hefei Institutes of Physical Science, Chinese Academy of Sciences, No. 350, Shushan Hu Road, Hefei, Anhui 230031, China
- Department of Molecular Pathology, Hefei Cancer Hospital, Chinese Academy of Sciences, No. 350, ShuShan Hu Road, Hefei, Anhui 230031, China
- Corresponding author: Zhiyou Fang, Anhui Province Key Laboratory of Medical Physics and Technology, Center of Medical Physics and Technology, Hefei Institutes of Physical Science, Chinese Academy of Sciences, No. 350, Shushan Hu Road, Hefei, Anhui 230031, China.
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23
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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: 65] [Impact Index Per Article: 13.0] [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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24
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Pan Y, Ballance H, Meng H, Gonzalez N, Kim SM, Abdurehman L, York B, Chen X, Schnytzer Y, Levy O, Dacso CC, McClung CA, O’Malley BW, Liu S, Zhu B. 12-h clock regulation of genetic information flow by XBP1s. PLoS Biol 2020; 18:e3000580. [PMID: 31935211 PMCID: PMC6959563 DOI: 10.1371/journal.pbio.3000580] [Citation(s) in RCA: 47] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2019] [Accepted: 12/11/2019] [Indexed: 12/15/2022] Open
Abstract
Our group recently characterized a cell-autonomous mammalian 12-h clock independent from the circadian clock, but its function and mechanism of regulation remain poorly understood. Here, we show that in mouse liver, transcriptional regulation significantly contributes to the establishment of 12-h rhythms of mRNA expression in a manner dependent on Spliced Form of X-box Binding Protein 1 (XBP1s). Mechanistically, the motif stringency of XBP1s promoter binding sites dictates XBP1s’s ability to drive 12-h rhythms of nascent mRNA transcription at dawn and dusk, which are enriched for basal transcription regulation, mRNA processing and export, ribosome biogenesis, translation initiation, and protein processing/sorting in the Endoplasmic Reticulum (ER)-Golgi in a temporal order consistent with the progressive molecular processing sequence described by the central dogma information flow (CEDIF). We further identified GA-binding proteins (GABPs) as putative novel transcriptional regulators driving 12-h rhythms of gene expression with more diverse phases. These 12-h rhythms of gene expression are cell autonomous and evolutionarily conserved in marine animals possessing a circatidal clock. Our results demonstrate an evolutionarily conserved, intricate network of transcriptional control of the mammalian 12-h clock that mediates diverse biological pathways. We speculate that the 12-h clock is coopted to accommodate elevated gene expression and processing in mammals at the two rush hours, with the particular genes processed at each rush hour regulated by the circadian and/or tissue-specific pathways. Distinct from the well-known 24-hour circadian clock, this study shows that the mammalian 12-hour clock upregulates genetic information flow capacity during the two "rush hours" (dawn and dusk) in a manner dependent on the transcription factor XBP1s.
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Affiliation(s)
- Yinghong Pan
- UPMC Genome Center, Pittsburgh, Pennsylvania, United States of America
| | - Heather Ballance
- Aging Institute of UPMC, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, United States of America
| | - Huan Meng
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, Texas, United States of America
| | - Naomi Gonzalez
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, Texas, United States of America
| | - Sam-Moon Kim
- Translational Neuroscience Program, Department of Psychiatry, Center for Neuroscience, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
| | - Leymaan Abdurehman
- Aging Institute of UPMC, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, United States of America
| | - Brian York
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, Texas, United States of America
| | - Xi Chen
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, Texas, United States of America
| | - Yisrael Schnytzer
- The Mina & Everard Goodman Faculty of Life Sciences, Bar-Ilan University, Ramat-Gan, Israel
| | - Oren Levy
- The Mina & Everard Goodman Faculty of Life Sciences, Bar-Ilan University, Ramat-Gan, Israel
| | - Clifford C. Dacso
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, Texas, United States of America
| | - Colleen A. McClung
- Translational Neuroscience Program, Department of Psychiatry, Center for Neuroscience, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
| | - Bert W. O’Malley
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, Texas, United States of America
| | - Silvia Liu
- Department of Pathology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, United States of America
- Pittsburgh Liver Research Center, University of Pittsburgh, Pennsylvania, United States of America
- * E-mail: (SL); (BZ)
| | - Bokai Zhu
- Aging Institute of UPMC, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, United States of America
- Pittsburgh Liver Research Center, University of Pittsburgh, Pennsylvania, United States of America
- Division of Endocrinology and Metabolism, Department of Medicine, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, United States of America
- * E-mail: (SL); (BZ)
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25
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Johnston BP, McCormick C. Herpesviruses and the Unfolded Protein Response. Viruses 2019; 12:E17. [PMID: 31877732 PMCID: PMC7019427 DOI: 10.3390/v12010017] [Citation(s) in RCA: 45] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2019] [Revised: 12/19/2019] [Accepted: 12/19/2019] [Indexed: 02/06/2023] Open
Abstract
Herpesviruses usurp cellular stress responses to promote viral replication and avoid immune surveillance. The unfolded protein response (UPR) is a conserved stress response that is activated when the protein load in the ER exceeds folding capacity and misfolded proteins accumulate. The UPR aims to restore protein homeostasis through translational and transcriptional reprogramming; if homeostasis cannot be restored, the UPR switches from "helper" to "executioner", triggering apoptosis. It is thought that the burst of herpesvirus glycoprotein synthesis during lytic replication causes ER stress, and that these viruses may have evolved mechanisms to manage UPR signaling to create an optimal niche for replication. The past decade has seen considerable progress in understanding how herpesviruses reprogram the UPR. Here we provide an overview of the molecular events of UPR activation, signaling and transcriptional outputs, and highlight key evidence that herpesviruses hijack the UPR to aid infection.
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Affiliation(s)
- Benjamin P. Johnston
- Department of Microbiology & Immunology, Dalhousie University, 5850 College Street, Halifax, NS B3H 4R2, Canada;
- Beatrice Hunter Cancer Research Institute, 5850 College Street, Halifax, NS B3H 4R2, Canada
| | - Craig McCormick
- Department of Microbiology & Immunology, Dalhousie University, 5850 College Street, Halifax, NS B3H 4R2, Canada;
- Beatrice Hunter Cancer Research Institute, 5850 College Street, Halifax, NS B3H 4R2, Canada
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26
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Woo YM, Kwak Y, Namkoong S, Kristjánsdóttir K, Lee SH, Lee JH, Kwak H. TED-Seq Identifies the Dynamics of Poly(A) Length during ER Stress. Cell Rep 2019; 24:3630-3641.e7. [PMID: 30257221 DOI: 10.1016/j.celrep.2018.08.084] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2017] [Revised: 07/02/2018] [Accepted: 08/28/2018] [Indexed: 12/31/2022] Open
Abstract
Post-transcriptional RNA processing is a core mechanism of gene expression control in cell stress response. The poly(A) tail influences mRNA translation and stability, but it is unclear whether there are global roles of poly(A)-tail lengths in cell stress. To address this, we developed tail-end displacement sequencing (TED-seq) for an efficient transcriptome-wide profiling of poly(A) lengths and applied it to endoplasmic reticulum (ER) stress in human cells. ER stress induced increases in the poly(A) lengths of certain mRNAs, including known ER stress regulators, XBP1, DDIT3, and HSPA5. Importantly, the mRNAs with increased poly(A) lengths are both translationally de-repressed and stabilized. Furthermore, mRNAs in stress-induced RNA granules have shorter poly(A) tails than in the cytoplasm, supporting the view that RNA processing is compartmentalized. In conclusion, TED-seq reveals that poly(A) length is dynamically regulated upon ER stress, with potential consequences for both translation and mRNA turnover.
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Affiliation(s)
- Yu Mi Woo
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY 14853, USA
| | - Yeonui Kwak
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY 14853, USA
| | - Sim Namkoong
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Katla Kristjánsdóttir
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY 14853, USA
| | - Seung Ha Lee
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY 14853, USA
| | - Jun Hee Lee
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Hojoong Kwak
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY 14853, USA.
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Pizzinga M, Harvey RF, Garland GD, Mordue R, Dezi V, Ramakrishna M, Sfakianos A, Monti M, Mulroney TE, Poyry T, Willis AE. The cell stress response: extreme times call for post‐transcriptional measures. WILEY INTERDISCIPLINARY REVIEWS-RNA 2019; 11:e1578. [DOI: 10.1002/wrna.1578] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2019] [Revised: 10/09/2019] [Accepted: 10/16/2019] [Indexed: 12/26/2022]
Affiliation(s)
| | | | | | - Ryan Mordue
- MRC Toxicology Unit University of Cambridge Leicester UK
| | - Veronica Dezi
- MRC Toxicology Unit University of Cambridge Leicester UK
| | | | | | - Mie Monti
- MRC Toxicology Unit University of Cambridge Leicester UK
| | | | - Tuija Poyry
- MRC Toxicology Unit University of Cambridge Leicester UK
| | - Anne E. Willis
- MRC Toxicology Unit University of Cambridge Leicester UK
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Zheng Z, Shang Y, Tao J, Zhang J, Sha B. Endoplasmic Reticulum Stress Signaling Pathways: Activation and Diseases. Curr Protein Pept Sci 2019; 20:935-943. [PMID: 31223084 DOI: 10.2174/1389203720666190621103145] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2019] [Revised: 05/31/2019] [Accepted: 06/03/2019] [Indexed: 02/06/2023]
Abstract
Secretory and membrane proteins are folded in the endoplasmic reticulum (ER) prior to their exit. When ER function is disturbed by exogenous and endogenous factors, such as heat shock, ultraviolet radiation, hypoxia, or hypoglycemia, the misfolded proteins may accumulate, promoting ER stress. To rescue this unfavorable situation, the unfolded protein response is activated to reduce misfolded proteins within the ER. Upon ER stress, the ER transmembrane sensor molecules inositol-requiring enzyme 1 (IRE1), RNA-dependent protein kinase (PKR)-like ER kinase (PERK), and activating transcription factor 6, are activated. Here, we discuss the mechanisms of PERK and IRE1 activation and describe two working models for ER stress initiation: the BiP-dependent model and the ligand-driven model. ER stress activation has been linked to multiple diseases, including cancers, Alzheimer's disease, and diabetes. Thus, the regulation of ER stress may provide potential therapeutic targets for these diseases.
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Affiliation(s)
- Zhi Zheng
- Department of Cell, Developmental and Integrative Biology (CDIB), University of Alabama at Birmingham, Birmingham, AL 35294, United States.,Department of General Surgery, Beijing Friendship Hospital, Capital Medical University, 95 Yong-an Road, Xi-Cheng District, Beijing 100050, China
| | - Yuxi Shang
- Department of Hematology, Fuxing Hospital, Eighth Clinical Medical College, Capital Medical University, Beijing 100038, China
| | - Jiahui Tao
- Department of Cell, Developmental and Integrative Biology (CDIB), University of Alabama at Birmingham, Birmingham, AL 35294, United States
| | - Jun Zhang
- Department of General Surgery, Beijing Friendship Hospital, Capital Medical University, 95 Yong-an Road, Xi-Cheng District, Beijing 100050, China
| | - Bingdong Sha
- Department of Cell, Developmental and Integrative Biology (CDIB), University of Alabama at Birmingham, Birmingham, AL 35294, United States
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29
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Xu R, Zhou J, Du XZ, Zhou XD, Li Q, Perelman JM, Kolosov VP. The role of the XBP-1/AGR2 signaling pathway in the regulation of airway Mucin5ac hypersecretion under hypoxia. Exp Cell Res 2019; 382:111442. [DOI: 10.1016/j.yexcr.2019.05.023] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2019] [Revised: 03/26/2019] [Accepted: 05/19/2019] [Indexed: 10/26/2022]
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30
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Bartoszewska S, Cabaj A, Dąbrowski M, Collawn JF, Bartoszewski R. miR-34c-5p modulates X-box-binding protein 1 (XBP1) expression during the adaptive phase of the unfolded protein response. FASEB J 2019; 33:11541-11554. [PMID: 31314593 DOI: 10.1096/fj.201900600rr] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
During endoplasmic reticulum (ER) stress conditions, an adaptive signaling network termed the unfolded protein response (UPR) is activated. The UPR's function is to increase ER protein-folding capacity in order to attenuate ER stress, restore ER homeostasis, and, most importantly, promote cell survival. X-box-binding protein 1 (XBP1) is one component of the UPR and is a proadaptive transcription factor that is subject to transcriptional, post-transcriptional, and post-translational control. In the present study, we identified a post-transcriptional mechanism mediated by miR-34c-5p that governs the expression of both the spliced (active) and unspliced (latent) forms of XBP1 mRNAs. We showed that miR-34c-5p directly attenuates spliced XBP1 (XBP1s) mRNA levels during ER stress and thus regulates the proadaptive component of the UPR that is mediated by XBP1s without interfering with the induction of apoptotic responses.-Bartoszewska, S., Cabaj, A., Dąbrowski, M., Collawn, J. F., Bartoszewski, R. miR-34c-5p modulates X-box-binding protein 1 (XBP1) expression during the adaptive phase of the unfolded protein response.
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Affiliation(s)
- Sylwia Bartoszewska
- Department of Inorganic Chemistry, Medical University of Gdansk, Gdansk, Poland
| | - Aleksandra Cabaj
- Laboratory of Bioinformatics, Nencki Institute of Experimental Biology, Polish Academy of Sciences, Warsaw, Poland
| | - Michał Dąbrowski
- Laboratory of Bioinformatics, Nencki Institute of Experimental Biology, Polish Academy of Sciences, Warsaw, Poland
| | - James F Collawn
- Department of Cell, Developmental, and Integrative Biology, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Rafal Bartoszewski
- Department of Biology and Pharmaceutical Botany, Medical University of Gdansk, Gdansk, Poland
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Widespread PERK-dependent repression of ER targets in response to ER stress. Sci Rep 2019; 9:4330. [PMID: 30867432 PMCID: PMC6416471 DOI: 10.1038/s41598-019-38705-5] [Citation(s) in RCA: 46] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2018] [Accepted: 01/04/2019] [Indexed: 12/11/2022] Open
Abstract
The UPR (Unfolded Protein Response) is a well-orchestrated response to ER protein folding and processing overload, integrating both transcriptional and translational outputs. Its three arms in mammalian cells, the PERK translational response arm, together with the ATF6 and IRE1-XBP1-mediated transcriptional arms, have been thoroughly investigated. Using ribosome footprint profiling, we performed a deep characterization of gene expression programs involved in the early and late ER stress responses, within WT or PERK -/- Mouse Embryonic Fibroblasts (MEFs). We found that both repression and activation gene expression programs, affecting hundreds of genes, are significantly hampered in the absence of PERK. Specifically, PERK -/- cells do not show global translational inhibition, nor do they specifically activate early gene expression programs upon short exposure to ER stress. Furthermore, while PERK -/- cells do activate/repress late ER-stress response genes, the response is substantially weaker. Importantly, we highlight a widespread PERK-dependent repression program, consisting of ER targeted proteins, including transmembrane proteins, glycoproteins, and proteins with disulfide bonds. This phenomenon occurs in various different cell types, and has a major translational regulatory component. Moreover, we revealed a novel interplay between PERK and the XBP1-ATF6 arms of the UPR, whereby PERK attenuates the expression of a specific subset of XBP1-ATF6 targets, further illuminating the complexity of the integrated ER stress response.
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32
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Ishikawa Y, Fedeles S, Marlier A, Zhang C, Gallagher AR, Lee AH, Somlo S. Spliced XBP1 Rescues Renal Interstitial Inflammation Due to Loss of Sec63 in Collecting Ducts. J Am Soc Nephrol 2019; 30:443-459. [PMID: 30745418 PMCID: PMC6405156 DOI: 10.1681/asn.2018060614] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2018] [Accepted: 01/07/2019] [Indexed: 01/13/2023] Open
Abstract
BACKGROUND SEC63 encodes a resident protein in the endoplasmic reticulum membrane that, when mutated, causes human autosomal dominant polycystic liver disease. Selective inactivation of Sec63 in all distal nephron segments in embryonic mouse kidney results in polycystin-1-mediated polycystic kidney disease (PKD). It also activates the Ire1α-Xbp1 branch of the unfolded protein response, producing Xbp1s, the active transcription factor promoting expression of specific genes to alleviate endoplasmic reticulum stress. Simultaneous inactivation of Xbp1 and Sec63 worsens PKD in this model. METHODS We explored the renal effects of postnatal inactivation of Sec63 alone or with concomitant inactivation of Xbp1 or Ire1α, specifically in the collecting ducts of neonatal mice. RESULTS The later onset of inactivation of Sec63 restricted to the collecting duct does not result in overt activation of the Ire1α-Xbp1 pathway or cause polycystin-1-dependent PKD. Inactivating Sec63 along with either Xbp1 or Ire1α in this model causes interstitial inflammation and associated fibrosis with decline in kidney function over several months. Re-expression of XBP1s in vivo completely rescues the chronic kidney injury observed after inactivation of Sec63 with either Xbp1 or Ire1α. CONCLUSIONS In the absence of Sec63, basal levels of Xbp1s activity in collecting ducts is both necessary and sufficient to maintain proteostasis (protein homeostasis) and protect against inflammation, myofibroblast activation, and kidney functional decline. The Sec63-Xbp1 double knockout mouse offers a novel genetic model of chronic tubulointerstitial kidney injury, using collecting duct proteostasis defects as a platform for discovery of signals that may underlie CKD of disparate etiologies.
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Affiliation(s)
| | | | | | | | | | - Ann-Hwee Lee
- Department of Pathology and Laboratory Medicine, Weill Cornell Medical College, New York, New York
| | - Stefan Somlo
- Departments of Internal Medicine and
- Genetics, Yale University School of Medicine, New Haven, Connecticut; and
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33
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CDNF induces the adaptive unfolded protein response and attenuates endoplasmic reticulum stress-induced cell death. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2018; 1865:1579-1589. [DOI: 10.1016/j.bbamcr.2018.08.012] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/28/2018] [Revised: 07/28/2018] [Accepted: 08/15/2018] [Indexed: 02/07/2023]
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34
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Shaheen A. Effect of the unfolded protein response on ER protein export: a potential new mechanism to relieve ER stress. Cell Stress Chaperones 2018; 23:797-806. [PMID: 29730847 PMCID: PMC6111102 DOI: 10.1007/s12192-018-0905-2] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2018] [Revised: 04/22/2018] [Accepted: 04/24/2018] [Indexed: 02/04/2023] Open
Abstract
The unfolded protein response (UPR) is an adaptive cellular response that aims to relieve endoplasmic reticulum (ER) stress via several mechanisms, including inhibition of protein synthesis and enhancement of protein folding and degradation. There is a controversy over the effect of the UPR on ER protein export. While some investigators suggested that ER export is inhibited during ER stress, others suggested the opposite. In this article, their conflicting studies are analyzed and compared in attempt to solve this controversy. The UPR appears indeed to enhance ER export, possibly via multiple mechanisms. However, another factor, which is the integrity of the folding machinery/environment inside ER, determines whether ER export will appear increased or decreased during experimentation. Also, different methods of stress induction appear to have different effects on ER export. Thus, improvement of ER export may represent a new mechanism by which the UPR alleviates ER stress. This may help researchers to understand how the UPR works inside cells and how to manipulate it to alter cell fate during stress, either to promote cell survival or death. This may open up new approaches for the treatment of ER stress-related diseases.
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Affiliation(s)
- Alaa Shaheen
- Kafr El-Sharakwa Medical Center, Aga, Dakahlia, Egypt.
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35
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Tsachaki M, Mladenovic N, Štambergová H, Birk J, Odermatt A. Hexose-6-phosphate dehydrogenase controls cancer cell proliferation and migration through pleiotropic effects on the unfolded-protein response, calcium homeostasis, and redox balance. FASEB J 2018; 32:2690-2705. [PMID: 29295867 PMCID: PMC5901385 DOI: 10.1096/fj.201700870rr] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Hexose-6-phosphate dehydrogenase (H6PD) produces reduced NADPH in the endoplasmic reticulum (ER) lumen. NADPH constitutes a cofactor for many reducing enzymes, and its inability to traverse biologic membranes makes in situ synthesis of NADPH in the ER lumen indispensable. The H6PD gene is amplified in several types of malignancies, and earlier work pointed toward a potential involvement of the enzyme in cancer cell growth. In the present study, we demonstrated a pivotal role of H6PD in proliferation and migratory potential of 3 human breast cancer cell lines. Knockdown of H6PD decreased proliferation and migration in SUM159, MCF7, and MDA-MB-453 cells. To understand the mechanism through which H6PD exerts its effects, we investigated the cellular changes after H6PD silencing in SUM159 cells. Knockdown of H6PD resulted in an increase in ER lumen oxidation, and down-regulation of many components of the unfolded protein response, including the transcription factors activating transcription factor-4, activating transcription factor-6, split X-box binding protein-1, and CCAAT/enhancer binding protein homologous protein. This effect was accompanied by an increase in sarco/endoplasmic reticulum Ca2+-ATPase-2 pump expression and an decrease in inositol trisphosphate receptor-III, which led to augmented levels of calcium in the ER. Further characterization of the molecular pathways involving H6PD could greatly broaden our understanding of how the ER microenvironment sustains malignant cell growth.-Tsachaki, M., Mladenovic, N., Štambergová, H., Birk, J., Odermatt, A. Hexose-6-phosphate dehydrogenase controls cancer cell proliferation and migration through pleiotropic effects on the unfolded protein response, calcium homeostasis, and redox balance.
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Affiliation(s)
- Maria Tsachaki
- Division of Molecular and Systems Toxicology, Department of Pharmaceutical Sciences, University of Basel, Basel, Switzerland
| | - Natasa Mladenovic
- Division of Molecular and Systems Toxicology, Department of Pharmaceutical Sciences, University of Basel, Basel, Switzerland
| | - Hana Štambergová
- Division of Molecular and Systems Toxicology, Department of Pharmaceutical Sciences, University of Basel, Basel, Switzerland
| | - Julia Birk
- Division of Molecular and Systems Toxicology, Department of Pharmaceutical Sciences, University of Basel, Basel, Switzerland
| | - Alex Odermatt
- Division of Molecular and Systems Toxicology, Department of Pharmaceutical Sciences, University of Basel, Basel, Switzerland
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36
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A Unique ISR Program Determines Cellular Responses to Chronic Stress. Mol Cell 2017; 68:885-900.e6. [PMID: 29220654 DOI: 10.1016/j.molcel.2017.11.007] [Citation(s) in RCA: 134] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2017] [Revised: 09/27/2017] [Accepted: 11/07/2017] [Indexed: 02/05/2023]
Abstract
The integrated stress response (ISR) is a homeostatic mechanism induced by endoplasmic reticulum (ER) stress. In acute/transient ER stress, decreased global protein synthesis and increased uORF mRNA translation are followed by normalization of protein synthesis. Here, we report a dramatically different response during chronic ER stress. This chronic ISR program is characterized by persistently elevated uORF mRNA translation and concurrent gene expression reprogramming, which permits simultaneous stress sensing and proteostasis. The program includes PERK-dependent switching to an eIF3-dependent translation initiation mechanism, resulting in partial, but not complete, translational recovery, which, together with transcriptional reprogramming, selectively bolsters expression of proteins with ER functions. Coordination of transcriptional and translational reprogramming prevents ER dysfunction and inhibits "foamy cell" development, thus establishing a molecular basis for understanding human diseases associated with ER dysfunction.
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37
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Zhao G, Fu Y, Cai Z, Yu F, Gong Z, Dai R, Hu Y, Zeng L, Xu Q, Kong W. Unspliced XBP1 Confers VSMC Homeostasis and Prevents Aortic Aneurysm Formation via FoxO4 Interaction. Circ Res 2017; 121:1331-1345. [PMID: 29089350 DOI: 10.1161/circresaha.117.311450] [Citation(s) in RCA: 84] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/05/2017] [Revised: 10/26/2017] [Accepted: 10/30/2017] [Indexed: 11/16/2022]
Abstract
RATIONALE Although not fully understood, the phenotypic transition of vascular smooth muscle cells exhibits at the early onset of the pathology of aortic aneurysms. Exploring the key regulators that are responsible for maintaining the contractile phenotype of vascular smooth muscle cells (VSMCs) may confer vascular homeostasis and prevent aneurysmal disease. XBP1 (X-box binding protein 1), which exists in a transcriptionally inactive unspliced form (XBP1u) and a spliced active form (XBP1s), is a key component in response to endoplasmic reticular stress. Compared with XBP1s, little is known about the role of XBP1u in vascular homeostasis and disease. OBJECTIVE We aim to investigate the role of XBP1u in VSMC phenotypic switching and the pathogenesis of aortic aneurysms. METHODS AND RESULTS XBP1u, but not XBP1s, was markedly repressed in the aorta during the early onset of aortic aneurysm in both angiotensin II-infused apolipoprotein E knockout (ApoE-/-) and CaPO4 (calcium phosphate)-induced C57BL/6J murine models, in parallel with a decrease in smooth muscle cell contractile apparatus proteins. In vivo studies revealed that XBP1 deficiency in smooth muscle cells caused VSMC dedifferentiation, enhanced vascular inflammation and proteolytic activity, and significantly aggravated both thoracic and abdominal aortic aneurysms in mice. XBP1 deficiency, but not an inhibition of XBP1 splicing, induced VSMC switching from the contractile phenotype to a proinflammatory and proteolytic phenotype. Mechanically, in the cytoplasm, XBP1u directly associated with the N terminus of FoxO4 (Forkhead box protein O 4), a recognized repressor of VSMC differentiation via the interaction and inhibition of myocardin. Blocking the XBP1u-FoxO4 interaction facilitated nuclear translocation of FoxO4, repressed smooth muscle cell marker genes expression, promoted proinflammatory and proteolytic phenotypic transitioning in vitro, and stimulated aortic aneurysm formation in vivo. CONCLUSIONS Our study revealed the pivotal role of the XBP1u-FoxO4-myocardin axis in maintaining the VSMC contractile phenotype and providing protection from aortic aneurysm formation.
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Affiliation(s)
- Guizhen Zhao
- From the Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Peking University, Key Laboratory of Molecular Cardiovascular Science, Ministry of Education, Beijing, P. R. China (G.Z., Y.F., Z.C., F.Y., Z.G., R.D., W.K.); and BHF Centre, School of Cardiovascular Medicine & Science, King's College London, United Kingdom (Y.H., L.Z., Q.X.)
| | - Yi Fu
- From the Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Peking University, Key Laboratory of Molecular Cardiovascular Science, Ministry of Education, Beijing, P. R. China (G.Z., Y.F., Z.C., F.Y., Z.G., R.D., W.K.); and BHF Centre, School of Cardiovascular Medicine & Science, King's College London, United Kingdom (Y.H., L.Z., Q.X.)
| | - Zeyu Cai
- From the Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Peking University, Key Laboratory of Molecular Cardiovascular Science, Ministry of Education, Beijing, P. R. China (G.Z., Y.F., Z.C., F.Y., Z.G., R.D., W.K.); and BHF Centre, School of Cardiovascular Medicine & Science, King's College London, United Kingdom (Y.H., L.Z., Q.X.)
| | - Fang Yu
- From the Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Peking University, Key Laboratory of Molecular Cardiovascular Science, Ministry of Education, Beijing, P. R. China (G.Z., Y.F., Z.C., F.Y., Z.G., R.D., W.K.); and BHF Centre, School of Cardiovascular Medicine & Science, King's College London, United Kingdom (Y.H., L.Z., Q.X.)
| | - Ze Gong
- From the Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Peking University, Key Laboratory of Molecular Cardiovascular Science, Ministry of Education, Beijing, P. R. China (G.Z., Y.F., Z.C., F.Y., Z.G., R.D., W.K.); and BHF Centre, School of Cardiovascular Medicine & Science, King's College London, United Kingdom (Y.H., L.Z., Q.X.)
| | - Rongbo Dai
- From the Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Peking University, Key Laboratory of Molecular Cardiovascular Science, Ministry of Education, Beijing, P. R. China (G.Z., Y.F., Z.C., F.Y., Z.G., R.D., W.K.); and BHF Centre, School of Cardiovascular Medicine & Science, King's College London, United Kingdom (Y.H., L.Z., Q.X.)
| | - Yanhua Hu
- From the Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Peking University, Key Laboratory of Molecular Cardiovascular Science, Ministry of Education, Beijing, P. R. China (G.Z., Y.F., Z.C., F.Y., Z.G., R.D., W.K.); and BHF Centre, School of Cardiovascular Medicine & Science, King's College London, United Kingdom (Y.H., L.Z., Q.X.)
| | - Lingfang Zeng
- From the Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Peking University, Key Laboratory of Molecular Cardiovascular Science, Ministry of Education, Beijing, P. R. China (G.Z., Y.F., Z.C., F.Y., Z.G., R.D., W.K.); and BHF Centre, School of Cardiovascular Medicine & Science, King's College London, United Kingdom (Y.H., L.Z., Q.X.)
| | - Qingbo Xu
- From the Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Peking University, Key Laboratory of Molecular Cardiovascular Science, Ministry of Education, Beijing, P. R. China (G.Z., Y.F., Z.C., F.Y., Z.G., R.D., W.K.); and BHF Centre, School of Cardiovascular Medicine & Science, King's College London, United Kingdom (Y.H., L.Z., Q.X.)
| | - Wei Kong
- From the Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Peking University, Key Laboratory of Molecular Cardiovascular Science, Ministry of Education, Beijing, P. R. China (G.Z., Y.F., Z.C., F.Y., Z.G., R.D., W.K.); and BHF Centre, School of Cardiovascular Medicine & Science, King's College London, United Kingdom (Y.H., L.Z., Q.X.).
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38
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Choi WG, Han J, Kim JH, Kim MJ, Park JW, Song B, Cha HJ, Choi HS, Chung HT, Lee IK, Park TS, Hatzoglou M, Choi HS, Yoo HJ, Kaufman RJ, Back SH. eIF2α phosphorylation is required to prevent hepatocyte death and liver fibrosis in mice challenged with a high fructose diet. Nutr Metab (Lond) 2017; 14:48. [PMID: 28781602 PMCID: PMC5537942 DOI: 10.1186/s12986-017-0202-6] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2016] [Accepted: 06/28/2017] [Indexed: 12/19/2022] Open
Abstract
BACKGROUND Dietary fructose can rapidly cause fatty liver in animals through de novo lipogenesis (DNL) and contribute to the development and severity of nonalcoholic fatty liver disease (NAFLD). In response to diverse cellular insults including endoplasmic reticulum (ER) and oxidative stress, phosphorylation of the eukaryotic translation initiation factor 2 alpha subunit (eIF2α) attenuates general translation initiation, allowing cells to conserve resources and initiate adaptive gene expression to restore homeostasis. The present study aimed to investigate the role of eIF2α phosphorylation in protecting against NAFLD induced by high fructose ingestion in a hepatocyte-specific eIF2α-phosphorylation-deficient mouse model. METHODS Hepatocyte-specific non-phosphorylatable (S51A) eIF2α knock-in (A/A;fTg/0;CreHep/0, A/AHep ) mice were generated by crossing A/A;fTg/fTg mice with the floxed WT eIF2α transgene (fTg) with Alfp-Cre recombinase transgenic S/A;CreHep/0 (S/A-CreHep ) mice. Hepatocyte-specific eIF2α-phosphorylation-deficient 3-month-old mice or 12-month-old mice were fed a 60% high fructose diet (HFrD) for 16 or 5 wks, and the effects of eIF2α-phosphorylation deficiency on NADP/NADPH and GSSG/GSH levels, ROS-defense gene expression, oxidative damage, cell death, and fibrosis were observed. RESULTS Prolonged fructose feeding to mice caused dysregulation of the unfolded protein response (UPR) sensor activation and UPR gene expression, and then led to decreased expression of several ROS defense genes including glutathione biogenesis genes. Nonetheless, these changes were not sufficient to induce the death of eIF2α phosphorylation-sufficient hepatocytes. However, there was a substantial increase in hepatocyte death and liver fibrosis in fructose-fed middle-aged mice deficient in hepatocyte-specific eIF2α phosphorylation because of diminished antioxidant capacity due to reduced expression of antioxidant enzymes (GPX1 and HO-1) and lower NADPH and glutathione levels, as well as a possible increase in ROS-induced damage from infiltrating NOX2-expressing leukocytes; all this led to a vicious cycle of hepatocyte death and leukocyte infiltration. CONCLUSION Our findings suggest that eIF2α phosphorylation maintains NADPH and GSH levels and controls the expression of ROS-defense genes, thereby protecting hepatocytes from oxidative stresses induced by fructose metabolism.
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Affiliation(s)
- Woo-Gyun Choi
- School of Biological Sciences, University of Ulsan, Ulsan, 44610 Republic of Korea
| | - Jaeseok Han
- Soonchunhyang Institute of Med-bio Science (SIMS), Soonchunhyang University, Cheonan-si, Choongchungnam-do, 31151 Republic of Korea.,Degenerative Diseases Program, Sanford Burnham Prebys Medical Discovery Institute, 10901 North Torrey Pines Road, La Jolla, CA 92037 USA
| | - Ji-Hyeon Kim
- School of Biological Sciences, University of Ulsan, Ulsan, 44610 Republic of Korea.,Biomedical Research Center, Asan Medical Center, College of Medicine, University of Ulsan, Seoul, 05505 Republic of Korea
| | - Mi-Jeong Kim
- School of Biological Sciences, University of Ulsan, Ulsan, 44610 Republic of Korea
| | - Jae-Woo Park
- School of Biological Sciences, University of Ulsan, Ulsan, 44610 Republic of Korea
| | - Benbo Song
- NGM Biopharmaceuticals, Inc., 333 Oyster Point Blvd, South San Francisco, CA 94080 USA
| | - Hee-Jeong Cha
- Department of Pathology, Ulsan University Hospital, University of Ulsan College of Medicine, Ulsan, 44043 Republic of Korea
| | - Hye-Seon Choi
- School of Biological Sciences, University of Ulsan, Ulsan, 44610 Republic of Korea
| | - Hun-Taeg Chung
- School of Biological Sciences, University of Ulsan, Ulsan, 44610 Republic of Korea
| | - In-Kyu Lee
- Department of Internal Medicine and Biochemistry and Cell Biology, Kyungpook National University School of Medicine, Daegu, 41944 Republic of Korea
| | - Tae-Sik Park
- Department of Life Science, Gachon University, Seongnam, Republic of Korea
| | - Maria Hatzoglou
- Department of Nutrition, Case Western Reserve University School of Medicine, Cleveland, OH 44106 USA
| | - Hueng-Sik Choi
- School of Biological Sciences and Technology, Chonnam National University, Gwangju, Republic of Korea
| | - Hyun Ju Yoo
- Biomedical Research Center, Asan Medical Center, College of Medicine, University of Ulsan, Seoul, 05505 Republic of Korea
| | - Randal J Kaufman
- Soonchunhyang Institute of Med-bio Science (SIMS), Soonchunhyang University, Cheonan-si, Choongchungnam-do, 31151 Republic of Korea
| | - Sung Hoon Back
- School of Biological Sciences, University of Ulsan, Ulsan, 44610 Republic of Korea
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Gong J, Wang XZ, Wang T, Chen JJ, Xie XY, Hu H, Yu F, Liu HL, Jiang XY, Fan HD. Molecular signal networks and regulating mechanisms of the unfolded protein response. J Zhejiang Univ Sci B 2017; 18:1-14. [PMID: 28070992 DOI: 10.1631/jzus.b1600043] [Citation(s) in RCA: 67] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Within the cell, several mechanisms exist to maintain homeostasis of the endoplasmic reticulum (ER). One of the primary mechanisms is the unfolded protein response (UPR). In this review, we primarily focus on the latest signal webs and regulation mechanisms of the UPR. The relationships among ER stress, apoptosis, and cancer are also discussed. Under the normal state, binding immunoglobulin protein (BiP) interacts with the three sensors (protein kinase RNA-like ER kinase (PERK), activating transcription factor 6 (ATF6), and inositol-requiring enzyme 1α (IRE1α)). Under ER stress, misfolded proteins interact with BiP, resulting in the release of BiP from the sensors. Subsequently, the three sensors dimerize and autophosphorylate to promote the signal cascades of ER stress. ER stress includes a series of positive and negative feedback signals, such as those regulating the stabilization of the sensors/BiP complex, activating and inactivating the sensors by autophosphorylation and dephosphorylation, activating specific transcription factors to enable selective transcription, and augmenting the ability to refold and export. Apart from the three basic pathways, vascular endothelial growth factor (VEGF)-VEGF receptor (VEGFR)-phospholipase C-γ (PLCγ)-mammalian target of rapamycin complex 1 (mTORC1) pathway, induced only in solid tumors, can also activate ATF6 and PERK signal cascades, and IRE1α also can be activated by activated RAC-alpha serine/threonine-protein kinase (AKT). A moderate UPR functions as a pro-survival signal to return the cell to its state of homeostasis. However, persistent ER stress will induce cells to undergo apoptosis in response to increasing reactive oxygen species (ROS), Ca2+ in the cytoplasmic matrix, and other apoptosis signal cascades, such as c-Jun N-terminal kinase (JNK), signal transducer and activator of transcription 3 (STAT3), and P38, when cellular damage exceeds the capacity of this adaptive response.
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Affiliation(s)
- Jing Gong
- Sichuan Radio and TV University, Chengdu 610073, China
| | - Xing-Zhi Wang
- Institute of Aging Research, School of Medicine, Hangzhou Normal University, Hangzhou 310036, China
| | - Tao Wang
- Institute of Aging Research, School of Medicine, Hangzhou Normal University, Hangzhou 310036, China
| | - Jiao-Jiao Chen
- Institute of Aging Research, School of Medicine, Hangzhou Normal University, Hangzhou 310036, China
| | - Xiao-Yuan Xie
- The Third Affiliated Hospital, Sun Yat-sen University, Guangzhou 510630, China
| | - Hui Hu
- Institute of Aging Research, School of Medicine, Hangzhou Normal University, Hangzhou 310036, China
| | - Fang Yu
- Institute of Aging Research, School of Medicine, Hangzhou Normal University, Hangzhou 310036, China
| | - Hui-Lin Liu
- Institute of Aging Research, School of Medicine, Hangzhou Normal University, Hangzhou 310036, China
| | - Xing-Yan Jiang
- Institute of Aging Research, School of Medicine, Hangzhou Normal University, Hangzhou 310036, China
| | - Han-Dong Fan
- Institute of Aging Research, School of Medicine, Hangzhou Normal University, Hangzhou 310036, China
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Hepatic Transcriptome Profiles of Mice with Diet-Induced Nonalcoholic Steatohepatitis Treated with Astaxanthin and Vitamin E. Int J Mol Sci 2017; 18:ijms18030593. [PMID: 28282876 PMCID: PMC5372609 DOI: 10.3390/ijms18030593] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2017] [Accepted: 03/04/2017] [Indexed: 02/06/2023] Open
Abstract
Astaxanthin alleviates hepatic lipid accumulation and peroxidation, inflammation, and fibrosis in mice with high-cholesterol, high-cholate, and high-fat (CL) diet-induced nonalcoholic steatohepatitis (NASH). It has been proposed as a potential new treatment to inhibit the progression of NASH in humans. In this study, we compared hepatic gene expression profiles after treatment with astaxanthin or the antioxidant vitamin E in mice with CL diet-induced NASH. Comprehensive gene expression analyses of the livers of mice fed a standard, CL, or CL diet containing astaxanthin or vitamin E for 12 weeks were performed using a DNA microarray. Both astaxanthin and vitamin E effectively improved gene expression associated with eukaryotic initiation factor-2 (EIF2) signaling, which is suppressed in NASH by endoplasmic reticulum (ER) stress in the liver. However, astaxanthin did not improve the expression of genes associated with mitochondrial dysfunction. Astaxanthin, but not vitamin E, was predicted to suppress the actions of ligand-dependent nuclear receptors peroxisome proliferator-activated receptors, (PPAR) α (PPARA) and PPARδ (PPARD), and to affect related molecules. Establishing a new therapy using astaxanthin will require elucidation of astaxanthin’s molecular action on the functions of PPARα and related molecules in the livers of mice with diet-induced NASH.
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West G, Gullmets J, Virtanen L, Li SP, Keinänen A, Shimi T, Mauermann M, Heliö T, Kaartinen M, Ollila L, Kuusisto J, Eriksson JE, Goldman RD, Herrmann H, Taimen P. Deleterious assembly of the lamin A/C mutant p.S143P causes ER stress in familial dilated cardiomyopathy. J Cell Sci 2016; 129:2732-43. [PMID: 27235420 DOI: 10.1242/jcs.184150] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2015] [Accepted: 05/20/2016] [Indexed: 01/12/2023] Open
Abstract
Mutation of the LMNA gene, encoding nuclear lamin A and lamin C (hereafter lamin A/C), is a common cause of familial dilated cardiomyopathy (DCM). Among Finnish DCM patients, the founder mutation c.427T>C (p.S143P) is the most frequently reported genetic variant. Here, we show that p.S143P lamin A/C is more nucleoplasmic and soluble than wild-type lamin A/C and accumulates into large intranuclear aggregates in a fraction of cultured patient fibroblasts as well as in cells ectopically expressing either FLAG- or GFP-tagged p.S143P lamin A. In fluorescence loss in photobleaching (FLIP) experiments, non-aggregated EGFP-tagged p.S143P lamin A was significantly more dynamic. In in vitro association studies, p.S143P lamin A failed to form appropriate filament structures but instead assembled into disorganized aggregates similar to those observed in patient cell nuclei. A whole-genome expression analysis revealed an elevated unfolded protein response (UPR) in cells expressing p.S143P lamin A/C. Additional endoplasmic reticulum (ER) stress induced by tunicamycin reduced the viability of cells expressing mutant lamin further. In summary, p.S143P lamin A/C affects normal lamina structure and influences the cellular stress response, homeostasis and viability.
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Affiliation(s)
- Gun West
- Department of Pathology, University of Turku and Turku University Hospital, 20520 Turku, Finland MediCity Research Laboratory, 20520 Turku, Finland
| | - Josef Gullmets
- Department of Pathology, University of Turku and Turku University Hospital, 20520 Turku, Finland MediCity Research Laboratory, 20520 Turku, Finland Faculty of Science and Engineering, Åbo Akademi University, 20520 Turku, Finland Turku Centre for Biotechnology, University of Turku and Åbo Akademi University, 20520 Turku, Finland
| | - Laura Virtanen
- Department of Pathology, University of Turku and Turku University Hospital, 20520 Turku, Finland MediCity Research Laboratory, 20520 Turku, Finland
| | - Song-Ping Li
- Department of Pathology, University of Turku and Turku University Hospital, 20520 Turku, Finland MediCity Research Laboratory, 20520 Turku, Finland
| | - Anni Keinänen
- Department of Pathology, University of Turku and Turku University Hospital, 20520 Turku, Finland MediCity Research Laboratory, 20520 Turku, Finland
| | - Takeshi Shimi
- Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
| | - Monika Mauermann
- Division of Molecular Genetics, German Cancer Research Center, 69120 Heidelberg, Germany Institute of Neuropathology, University Hospital Erlangen, 91054 Erlangen, Germany
| | - Tiina Heliö
- Heart and Lung Center Helsinki University Hospital and University of Helsinki, 00029 Helsinki, Finland
| | - Maija Kaartinen
- Heart and Lung Center Helsinki University Hospital and University of Helsinki, 00029 Helsinki, Finland
| | - Laura Ollila
- Heart and Lung Center Helsinki University Hospital and University of Helsinki, 00029 Helsinki, Finland
| | - Johanna Kuusisto
- Department of Medicine, University of Eastern Finland, 70211 Kuopio, Finland
| | - John E Eriksson
- Faculty of Science and Engineering, Åbo Akademi University, 20520 Turku, Finland Turku Centre for Biotechnology, University of Turku and Åbo Akademi University, 20520 Turku, Finland
| | - Robert D Goldman
- Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
| | - Harald Herrmann
- Division of Molecular Genetics, German Cancer Research Center, 69120 Heidelberg, Germany Institute of Neuropathology, University Hospital Erlangen, 91054 Erlangen, Germany
| | - Pekka Taimen
- Department of Pathology, University of Turku and Turku University Hospital, 20520 Turku, Finland MediCity Research Laboratory, 20520 Turku, Finland
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Philippe C, Dubrac A, Quelen C, Desquesnes A, Van Den Berghe L, Ségura C, Filleron T, Pyronnet S, Prats H, Brousset P, Touriol C. PERK mediates the IRES-dependent translational activation of mRNAs encoding angiogenic growth factors after ischemic stress. Sci Signal 2016; 9:ra44. [PMID: 27141928 DOI: 10.1126/scisignal.aaf2753] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Angiogenesis is induced by various conditions, including hypoxia. Although cap-dependent translation is globally inhibited during ischemia, the mRNAs encoding two important proangiogenic growth factors, vascular endothelial growth factor (VEGF) and fibroblast growth factor 2 (FGF-2), are translated at early time points in ischemic muscle. The translation of these mRNAs can occur through internal ribosome entry sites (IRESs), rather than through cap-dependent translation. Hypoxic conditions also induce the unfolded protein response (UPR) and endoplasmic reticulum (ER) stress, leading us to assess the interplay between hypoxia, ER stress, and IRES-mediated translation of FGF-2 and VEGF We found that unlike cap-dependent translation, translation through FGF-2 and VEGF IRESs was efficient in cells and transgenic mice subjected to ER stress-inducing stimuli. We identified PERK, a kinase that is activated by ER stress, as the driver of VEGF and FGF-2 IRES-mediated translation in cells and in mice expressing IRES-driven reporter genes and exposed to hypoxic stress. These results demonstrate the role of IRES-dependent translation in the induction of the proangiogenic factors VEGF and FGF-2 in response to acute hypoxic stress. Furthermore, the PERK pathway could be a viable pharmacological target to improve physiological responses to ischemic situations.
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Affiliation(s)
- Céline Philippe
- INSERM, UMR 1037, CRCT (Cancer Research Center of Toulouse), F-31037 Toulouse, France. Université Toulouse III Paul Sabatier, F-31000 Toulouse, France
| | - Alexandre Dubrac
- INSERM, UMR 1037, CRCT (Cancer Research Center of Toulouse), F-31037 Toulouse, France. Université Toulouse III Paul Sabatier, F-31000 Toulouse, France
| | - Cathy Quelen
- INSERM, UMR 1037, CRCT (Cancer Research Center of Toulouse), F-31037 Toulouse, France. Université Toulouse III Paul Sabatier, F-31000 Toulouse, France
| | - Aurore Desquesnes
- INSERM US006, CREFRE (Centre régional d'exploration fonctionnelle et de ressources expérimentales), F-31000 Toulouse, France
| | - Loic Van Den Berghe
- INSERM, UMR 1037, CRCT (Cancer Research Center of Toulouse), F-31037 Toulouse, France. Université Toulouse III Paul Sabatier, F-31000 Toulouse, France. Vectorology Platform, CRCT Technological Pole, F-31037 Toulouse, France
| | - Christèle Ségura
- INSERM, UMR 1037, CRCT (Cancer Research Center of Toulouse), F-31037 Toulouse, France. Université Toulouse III Paul Sabatier, F-31000 Toulouse, France. Vectorology Platform, CRCT Technological Pole, F-31037 Toulouse, France
| | - Thomas Filleron
- Clinical Trial Office, Department of Statistics, IUCT (Institut Universitaire du Cancer de Toulouse)-Oncopole, F-31100 Toulouse, France
| | - Stéphane Pyronnet
- INSERM, UMR 1037, CRCT (Cancer Research Center of Toulouse), F-31037 Toulouse, France. Université Toulouse III Paul Sabatier, F-31000 Toulouse, France. Laboratoire d'Excellence Toulouse Cancer (TOUCAN), F-31037 Toulouse, France
| | - Hervé Prats
- INSERM, UMR 1037, CRCT (Cancer Research Center of Toulouse), F-31037 Toulouse, France. Université Toulouse III Paul Sabatier, F-31000 Toulouse, France
| | - Pierre Brousset
- INSERM, UMR 1037, CRCT (Cancer Research Center of Toulouse), F-31037 Toulouse, France. Université Toulouse III Paul Sabatier, F-31000 Toulouse, France. Laboratoire d'Excellence Toulouse Cancer (TOUCAN), F-31037 Toulouse, France. Department of Pathology, IUCT-Oncopole, F-31100 Toulouse, France
| | - Christian Touriol
- INSERM, UMR 1037, CRCT (Cancer Research Center of Toulouse), F-31037 Toulouse, France. Université Toulouse III Paul Sabatier, F-31000 Toulouse, France.
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Moore K, Hollien J. Ire1-mediated decay in mammalian cells relies on mRNA sequence, structure, and translational status. Mol Biol Cell 2015; 26:2873-84. [PMID: 26108623 PMCID: PMC4571326 DOI: 10.1091/mbc.e15-02-0074] [Citation(s) in RCA: 89] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2015] [Accepted: 06/16/2015] [Indexed: 12/16/2022] Open
Abstract
Endoplasmic reticulum (ER) stress induces the degradation of mRNAs by Ire1. In mammalian cells, this process depends on specific stem-loop structures in the target mRNAs and on Perk, a second sensor of ER stress. Perk appears to be required to translationally attenuate the stem-loop regions of target mRNAs. Endoplasmic reticulum (ER) stress occurs when misfolded proteins overwhelm the capacity of the ER, resulting in activation of the unfolded protein response (UPR). Ire1, an ER transmembrane nuclease and conserved transducer of the UPR, cleaves the mRNA encoding the transcription factor Xbp1 at a dual stem-loop (SL) structure, leading to Xbp1 splicing and activation. Ire1 also cleaves other mRNAs localized to the ER membrane through regulated Ire1-dependent decay (RIDD). We find that during acute ER stress in mammalian cells, Xbp1-like SLs within the target mRNAs are necessary for RIDD. Furthermore, depletion of Perk, a UPR transducer that attenuates translation during ER stress, inhibits RIDD in a substrate-specific manner. Artificially blocking translation of the SL region of target mRNAs fully restores RIDD in cells depleted of Perk, suggesting that ribosomes disrupt SL formation and/or Ire1 binding. This coordination between Perk and Ire1 may serve to spatially and temporally regulate RIDD.
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Affiliation(s)
- Kristin Moore
- Department of Biology and Center for Cell and Genome Science, University of Utah, Salt Lake City, UT 84112
| | - Julie Hollien
- Department of Biology and Center for Cell and Genome Science, University of Utah, Salt Lake City, UT 84112
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Krokowski D, Jobava R, Guan BJ, Farabaugh K, Wu J, Majumder M, Bianchi MG, Snider MD, Bussolati O, Hatzoglou M. Coordinated Regulation of the Neutral Amino Acid Transporter SNAT2 and the Protein Phosphatase Subunit GADD34 Promotes Adaptation to Increased Extracellular Osmolarity. J Biol Chem 2015; 290:17822-17837. [PMID: 26041779 DOI: 10.1074/jbc.m114.636217] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2015] [Indexed: 02/04/2023] Open
Abstract
Cells respond to shrinkage induced by increased extracellular osmolarity via programmed changes in gene transcription and mRNA translation. The immediate response to this stress includes the induction of expression of the neutral amino acid transporter SNAT2. Increased SNAT2-mediated uptake of neutral amino acids is an essential adaptive mechanism for restoring cell volume. In contrast, stress-induced phosphorylation of the α subunit of the translation initiation factor eIF2 (eIF2α) can promote apoptosis. Here we show that the response to mild hyperosmotic stress involves regulation of the phosphorylation of eIF2α by increased levels of GADD34, a regulatory subunit of protein phosphatase 1 (PP1). The induction of GADD34 was dependent on transcriptional control by the c-Jun-binding cAMP response element in the GADD34 gene promoter and posttranscriptional stabilization of its mRNA. This mechanism differs from the regulation of GADD34 expression by other stresses that involve activating transcription factor 4 (ATF4). ATF4 was not translated during hyperosmotic stress despite an increase in eIF2α phosphorylation. The SNAT2-mediated increase in amino acid uptake was enhanced by increased GADD34 levels in a manner involving decreased eIF2α phosphorylation. It is proposed that the induction of the SNAT2/GADD34 axis enhances cell survival by promoting the immediate adaptive response to stress.
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Affiliation(s)
- Dawid Krokowski
- Departments of Pharmacology, Case Western Reserve University, School of Medicine, Cleveland, Ohio 44106.
| | - Raul Jobava
- Departments of Pharmacology, Case Western Reserve University, School of Medicine, Cleveland, Ohio 44106
| | - Bo-Jhih Guan
- Departments of Pharmacology, Case Western Reserve University, School of Medicine, Cleveland, Ohio 44106
| | - Kenneth Farabaugh
- Departments of Pharmacology, Case Western Reserve University, School of Medicine, Cleveland, Ohio 44106
| | - Jing Wu
- Departments of Pharmacology, Case Western Reserve University, School of Medicine, Cleveland, Ohio 44106
| | - Mithu Majumder
- Departments of Pharmacology, Case Western Reserve University, School of Medicine, Cleveland, Ohio 44106
| | - Massimiliano G Bianchi
- Department of Biomedical, Biotechnological, and Translational Sciences, University of Parma, 43100 Parma, Italy
| | - Martin D Snider
- Departments of Biochemistry, Case Western Reserve University, School of Medicine, Cleveland, Ohio 44106
| | - Ovidio Bussolati
- Department of Biomedical, Biotechnological, and Translational Sciences, University of Parma, 43100 Parma, Italy
| | - Maria Hatzoglou
- Departments of Pharmacology, Case Western Reserve University, School of Medicine, Cleveland, Ohio 44106.
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45
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Wu R, Zhang QH, Lu YJ, Ren K, Yi GH. Involvement of the IRE1α-XBP1 pathway and XBP1s-dependent transcriptional reprogramming in metabolic diseases. DNA Cell Biol 2015; 34:6-18. [PMID: 25216212 DOI: 10.1089/dna.2014.2552] [Citation(s) in RCA: 84] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
The X-box binding protein 1 (XBP1) is not only an important component of the unfolded protein response (UPR), but also an important nuclear transcription factor. Upon endoplasmic reticulum stress, XBP1 is spliced by inositol-requiring enzyme 1 (IRE1), thereby generating functional spliced XBP1 (XBP1s). XBP1s functions by translocating into the nucleus to initiate transcriptional programs that regulate a subset of UPR- and non-UPR-associated genes involved in the pathophysiological processes of various diseases. Recent reports have implicated XBP1 in metabolic diseases. This review summarizes the effects of XBP1-mediated regulation on lipid metabolism, glucose metabolism, obesity, and atherosclerosis. Additionally, for the first time, we present XBP1s-dependent transcriptional reprogramming in metabolic diseases under different conditions, including pathology and physiology. Understanding the function of XBP1 in metabolic diseases may provide a basic knowledge for the development of novel therapeutic targets for ameliorating these diseases.
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Affiliation(s)
- Rong Wu
- 1 Key Laboratory for Atherosclerology of Hunan Province, Institute of Cardiovascular Research, University of South China , Hengyang, China
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46
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Majumder M, Mitchell D, Merkulov S, Wu J, Guan BJ, Snider MD, Krokowski D, Yee VC, Hatzoglou M. Residues required for phosphorylation of translation initiation factor eIF2α under diverse stress conditions are divergent between yeast and human. Int J Biochem Cell Biol 2014; 59:135-41. [PMID: 25541374 DOI: 10.1016/j.biocel.2014.12.004] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2014] [Revised: 11/26/2014] [Accepted: 12/15/2014] [Indexed: 01/28/2023]
Abstract
PERK, PKR, HRI and GCN2 are the four mammalian kinases that phosphorylate the α subunit of the eukaryotic translation initiation factor 2 (eIF2α) on Ser51. This phosphorylation event is conserved among many species and attenuates protein synthesis in response to diverse stress conditions. In contrast, Saccharmyces cerevisiae expresses only the GCN2 kinase. It was demonstrated previously in S. cerevisiae that single point mutations in eIF2α's N-terminus severely impaired phosphorylation at Ser51. To assess whether similar recognition patterns are present in mammalian eIF2α, we expressed human eIF2α's with these mutations in mouse embryonic fibroblasts and assessed their phosphorylation under diverse stress conditions. Some of the mutations prevented the stress-induced phosphorylation of eIF2α by all mammalian kinases, thus defining amino acid residues in eIF2α (Gly 30, Leu 50, and Asp 83) that are required for substrate recognition. We also identified residues that were less critical or not required for recognition by the mammalian kinases (Ala 31, Met 44, Lys 79, and Tyr 81), even though they were essential for recognition of the yeast eIF2α by GCN2. We propose that mammalian eIF2α kinases evolved to maximize their interactions with the evolutionarily conserved Ser51 residue of eIF2α in response to diverse stress conditions, thus adding to the complex signaling pathways that mammalian cells have over simpler organisms.
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Affiliation(s)
- Mithu Majumder
- Department of Pharmacology, School of Medicine, Case Western Reserve University, Cleveland, OH 44106, United States
| | - Daniel Mitchell
- Department of Pharmacology, School of Medicine, Case Western Reserve University, Cleveland, OH 44106, United States
| | - Sergei Merkulov
- Virogene Technology, 11000 Cedar Ave., Cleveland, OH, United States
| | - Jing Wu
- Department of Pharmacology, School of Medicine, Case Western Reserve University, Cleveland, OH 44106, United States
| | - Bo-Jhih Guan
- Department of Pharmacology, School of Medicine, Case Western Reserve University, Cleveland, OH 44106, United States
| | - Martin D Snider
- Department of Biochemistry, School of Medicine, Case Western Reserve University, Cleveland, OH 44106, United States
| | - Dawid Krokowski
- Department of Pharmacology, School of Medicine, Case Western Reserve University, Cleveland, OH 44106, United States
| | - Vivien C Yee
- Department of Biochemistry, School of Medicine, Case Western Reserve University, Cleveland, OH 44106, United States.
| | - Maria Hatzoglou
- Department of Pharmacology, School of Medicine, Case Western Reserve University, Cleveland, OH 44106, United States.
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47
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Koromilas AE. Roles of the translation initiation factor eIF2α serine 51 phosphorylation in cancer formation and treatment. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2014; 1849:871-80. [PMID: 25497381 DOI: 10.1016/j.bbagrm.2014.12.007] [Citation(s) in RCA: 93] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/29/2014] [Revised: 12/03/2014] [Accepted: 12/07/2014] [Indexed: 01/12/2023]
Abstract
Cells respond to various forms of stress by activating anti-proliferative pathways, which allow them to correct the damage caused by stress before re-entering proliferation. If the damage, however, is beyond repair, stressed cells are eliminated from the host by undergoing death. The balance between cell survival and death is essential for cancer formation and is determined by several key pathways that impact on different stages of gene expression. In recent years, it has become evident that phosphorylation of the alpha (α) subunit of the translation initiation factor eIF2 at serine 51 (eIF2αS51P) is an important determinant of cell fate in response to stress. Induction of eIF2αS51P is mediated by a family of four kinases namely, HRI, PKR, PERK and GCN2, each of which responds to distinct forms of stress. Increased eIF2αS51P results in a global inhibition of protein synthesis but at the same time enhances the translation of select mRNAs encoding for proteins that control cell adaptation to stress. Short-term induction of eIF2αS51P has been associated with cell survival whereas long-term induction with cell death. Studies in mouse and human models of cancer have provided compelling evidence that eIF2αS51P plays an essential role in stress-induced tumorigenesis. Increased eIF2αS51P exhibits cell autonomous as well as immune regulatory effects, which can influence tumor growth and the efficacy of anti-tumor therapies. The findings suggest that eIF2αS51P may be of prognostic value and a suitable target for the design and implementation of effective anti-tumor therapies. This article is part of a Special Issue entitled: Translation and Cancer.
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Affiliation(s)
- Antonis E Koromilas
- Lady Davis Institute for Medical Research-McGill University, Sir Mortimer B. Davis-Jewish General Hospital, Montreal, Quebec H3T 1E2, Canada; Department of Oncology, Faculty of Medicine, McGill University, Montreal, Quebec H2W 1S6, Canada.
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48
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Jurkin J, Henkel T, Nielsen AF, Minnich M, Popow J, Kaufmann T, Heindl K, Hoffmann T, Busslinger M, Martinez J. The mammalian tRNA ligase complex mediates splicing of XBP1 mRNA and controls antibody secretion in plasma cells. EMBO J 2014; 33:2922-36. [PMID: 25378478 PMCID: PMC4282640 DOI: 10.15252/embj.201490332] [Citation(s) in RCA: 153] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
The unfolded protein response (UPR) is a conserved stress-signaling pathway activated after accumulation of unfolded proteins within the endoplasmic reticulum (ER). Active UPR signaling leads to unconventional, enzymatic splicing of XBP1 mRNA enabling expression of the transcription factor XBP1s to control ER homeostasis. While IRE1 has been identified as the endoribonuclease required for cleavage of this mRNA, the corresponding ligase in mammalian cells has remained elusive. Here, we report that RTCB, the catalytic subunit of the tRNA ligase complex, and its co-factor archease mediate XBP1 mRNA splicing both in vitro and in vivo. Depletion of RTCB in plasma cells of Rtcb(fl/fl) Cd23-Cre mice prevents XBP1s expression, which normally is strongly induced during plasma cell development. RTCB-depleted plasma cells show reduced and disorganized ER structures as well as severe defects in antibody secretion. Targeting RTCB and/or archease thus represents a promising strategy for the treatment of a growing number of diseases associated with elevated expression of XBP1s.
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Affiliation(s)
- Jennifer Jurkin
- Institute of Molecular Biotechnology of the Austrian Academy of Sciences (IMBA), Vienna, Austria
| | - Theresa Henkel
- Institute of Molecular Biotechnology of the Austrian Academy of Sciences (IMBA), Vienna, Austria
| | | | | | - Johannes Popow
- European Molecular Biology Laboratory (EMBL), Heidelberg, Germany
| | - Therese Kaufmann
- Institute of Molecular Biotechnology of the Austrian Academy of Sciences (IMBA), Vienna, Austria
| | - Katrin Heindl
- Whitehead Institute for Biomedical Research, Cambridge, MA, USA
| | | | | | - Javier Martinez
- Institute of Molecular Biotechnology of the Austrian Academy of Sciences (IMBA), Vienna, Austria
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Palomer X, Capdevila-Busquets E, Garreta G, Davidson MM, Vázquez-Carrera M. PPARα atenúa el estrés del retículo endoplasmático inducido por palmitato en células cardíacas humanas por medio de la inducción de la actividad AMPK. CLINICA E INVESTIGACION EN ARTERIOSCLEROSIS 2014; 26:255-67. [DOI: 10.1016/j.arteri.2014.02.003] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/31/2013] [Accepted: 02/13/2014] [Indexed: 02/02/2023]
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Matos L, Gouveia AM, Almeida H. ER Stress Response in Human Cellular Models of Senescence. J Gerontol A Biol Sci Med Sci 2014; 70:924-35. [PMID: 25149687 DOI: 10.1093/gerona/glu129] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2014] [Accepted: 06/26/2014] [Indexed: 11/13/2022] Open
Abstract
The aging process is characterized by progressive accumulation of damaged biomolecules in the endoplasmic reticulum, as result of increased oxidative stress accompanying cellular senescence. In agreement, we hypothesized that WI-38 human cellular models of replicative senescence and stress-induced premature senescence (SIPS) induced by hydrogen peroxide (H2O2-SIPS) or copper sulfate (CuSO4-SIPS) would present endoplasmic reticulum chaperoning mechanisms impairment and unfolded protein response activation. Results show that in replicative senescence and CuSO4-SIPS, immunoglobulin binding protein, calnexin, protein disulfide isomerase, and ER oxireductin-1 levels adjust to restore proteostasis and inositol-requiring enzyme-1 (IRE1)-, activating transcription factor 6 (ATF6)-, and pancreatic ER kinase (PERK)-mediated unfolded protein response are activated. However, H2O2-SIPS does not exhibit IRE1 and ATF6 pathways activation but a PERK-mediated upregulation of CCAAT/enhancer-binding protein homologous protein, showing that CuSO4-SIPS mimics better the endoplasmic reticulum molecular events of replicative senescence than H2O2-SIPS. Moreover, unfolded protein response activation is required for both SIPS models induction, because PERK and IRE1 inhibitors decreased senescence-associated beta-galactosidase appearance. In CuSO4-SIPS, the decrease in senescence levels is associated with PERK-driven, but IRE1 independent, cell cycle arrest while in H2O2-SIPS cell proliferation is PERK independent. These results add a step further on the molecular mechanisms that regulate senescence induction; moreover, they validate CuSO4-SIPS model as a useful tool to study cellular stress responses during aging, hoping to postpone age-related health decline.
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Affiliation(s)
- Liliana Matos
- Faculdade de Medicina do Porto, Departamento de Biologia Experimental, IBMC-Instituto de Biologia Molecular e Celular, Ageing and Stress, Universidade do Porto, Porto, Portugal. Faculdade de Ciências da Nutrição e Alimentação, Universidade do Porto, Porto, Portugal
| | - Alexandra Monteiro Gouveia
- Faculdade de Medicina do Porto, Departamento de Biologia Experimental, IBMC-Instituto de Biologia Molecular e Celular, Ageing and Stress, Universidade do Porto, Porto, Portugal. Faculdade de Ciências da Nutrição e Alimentação, Universidade do Porto, Porto, Portugal
| | - Henrique Almeida
- Faculdade de Medicina do Porto, Departamento de Biologia Experimental, IBMC-Instituto de Biologia Molecular e Celular, Ageing and Stress, Universidade do Porto, Porto, Portugal.
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