351
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Differential activation of ER stress pathways in myelinating cerebellar tracts. Int J Dev Neurosci 2015; 47:347-60. [PMID: 26297908 DOI: 10.1016/j.ijdevneu.2015.08.002] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2015] [Revised: 08/12/2015] [Accepted: 08/13/2015] [Indexed: 11/22/2022] Open
Abstract
Myelin production during brain development requires an increase in membrane protein and lipid production in oligodendrocytes and this primarily occurs in the endoplasmic reticulum (ER), an organelle which initiates the Unfolded Protein Response (UPR) when under stress. We hypothesise that the UPR is activated in white matter tracts during myelination in order to expand the ER capacity of oligodendrocytes. Using early and late stage markers, critical myelination time points were identified by immunohistochemistry in developing rat cerebellum. These were correlated to peaks in ER stress signalling by staining for activated UPR transducers (pIRE1, ATF6 and pPERK) and associated downstream molecules (peIF2α, PDI, GRP78, GRP94, CHOP and calreticulin) in cerebellar tracts III and IV. Gene expression in developing cerebellum was assessed by qPCR. Actively myelinating tracts were shown to have differential expression of pIRE1, PERK and ATF6 as well as UPR targets GRP94, GRP78 and PDI. Activated pIRE1-positive cells were widespread at P14 and P17 and at significantly higher numbers during myelination than at other stages. Nuclear-localised ATF6 (indicative of the active transcription factor) peaked at P10, concurrent with the initial phase of myelination. The percentage of cells positive for pPERK was less than 1% at postnatal ages but increased significantly in adult tissue. The downstream targets GRP78, GRP94 and PDI were significantly up-regulated at P17 compared to P7 and remained significantly elevated in adults. The majority of cells positive for these markers and ATF6 were oligodendrocytes as confirmed by dual-labelling. Although gene expression in the cerebellum for GRP78, GRP94 and PDI did not change significantly over time, ATF6 and XBP1s both showed significant fold changes between early and late timepoints. This data helps promote understanding of events occurring during developmental myelination and may have implications for the development of reparative treatments in diseases such as multiple sclerosis.
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352
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Treacy-Abarca S, Mukherjee S. Legionella suppresses the host unfolded protein response via multiple mechanisms. Nat Commun 2015. [PMID: 26219498 PMCID: PMC4519984 DOI: 10.1038/ncomms8887] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
The intracellular pathogen, Legionella pneumophila, secretes ∼300 effector proteins to modulate the host environment. Given the intimate interaction between L. pneumophila and the endoplasmic reticulum, we investigated the role of the host unfolded protein response (UPR) during L. pneumophila infection. Interestingly, we show that the host identifies L. pneumophila infection as a form of endoplasmic reticulum stress and the sensor pATF6 is processed to generate pATF6(N), a transcriptional activator of downstream UPR genes. However, L. pneumophila is able to suppress the UPR and block the translation of prototypical UPR genes, BiP and CHOP. Furthermore, biochemical studies reveal that L. pneumophila uses two effectors (Lgt1 and Lgt2) to inhibit the splicing of XBP1u mRNA to spliced XBP1 (XBP1s), an UPR response regulator. Thus, we demonstrate that L. pneumophila is able to inhibit the UPR by multiple mechanisms including blocking XBP1u splicing and causing translational repression. This observation highlights the utility of L. pneumophila as a powerful tool for studying a critical protein homeostasis regulator. The bacterium Legionella pneumophila, a causative agent of severe pneumonia, replicates inside an endoplasmic reticulum-like organelle in the host cells. Here, Treacy-Abarca and Mukherjee show that the pathogen dampens the host's unfolded protein response (UPR) pathway by multiple mechanisms.
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Affiliation(s)
- Sean Treacy-Abarca
- 1] Department of Microbiology and Immunology, University of California, San Francisco, 513 Parnassus Avenue, San Francisco, California 94143-0552, USA [2] Department of Microbiology and Immunology, George Williams Hooper Foundation, 513 Parnassus Avenue, Box 0552, Rm HSW 1522, San Francisco, California 94143-0552, USA
| | - Shaeri Mukherjee
- 1] Department of Microbiology and Immunology, University of California, San Francisco, 513 Parnassus Avenue, San Francisco, California 94143-0552, USA [2] Department of Microbiology and Immunology, George Williams Hooper Foundation, 513 Parnassus Avenue, Box 0552, Rm HSW 1522, San Francisco, California 94143-0552, USA
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353
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Iwao C, Shidoji Y. Polyunsaturated Branched-Chain Fatty Acid Geranylgeranoic Acid Induces Unfolded Protein Response in Human Hepatoma Cells. PLoS One 2015; 10:e0132761. [PMID: 26186544 PMCID: PMC4506074 DOI: 10.1371/journal.pone.0132761] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2015] [Accepted: 06/17/2015] [Indexed: 01/22/2023] Open
Abstract
The acyclic diterpenoid acid geranylgeranoic acid (GGA) has been reported to induce autophagic cell death in several human hepatoma-derived cell lines; however, the molecular mechanism for this remains unknown. In the present study, several diterpenoids were examined for ability to induce XBP1 splicing and/or lipotoxicity for human hepatoma cell lines. Here we show that three groups of diterpenoids emerged: 1) GGA, 2,3-dihydro GGA and 9-cis retinoic acid induce cell death and XBP1 splicing; 2) all-trans retinoic acid induces XBP1 splicing but little cell death; and 3) phytanic acid, phytenic acid and geranylgeraniol induce neither cell death nor XBP1 splicing. GGA-induced ER stress/ unfolded protein response (UPR) and its lipotoxicity were both blocked by co-treatment with oleic acid. The blocking activity of oleic acid for GGA-induced XBP1 splicing was not attenuated by methylation of oleic acid. These findings strongly suggest that GGA at micromolar concentrations induces the so-called lipid-induced ER stress response/UPR, which is oleate-suppressive, and shows its lipotoxicity in human hepatoma cells.
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Affiliation(s)
- Chieko Iwao
- Molecular and Cellular Biology, Graduate School of Human Health Science, University of Nagasaki, Nagasaki, Japan
| | - Yoshihiro Shidoji
- Molecular and Cellular Biology, Graduate School of Human Health Science, University of Nagasaki, Nagasaki, Japan
- * E-mail:
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354
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Bettigole SE, Lis R, Adoro S, Lee AH, Spencer LA, Weller PF, Glimcher LH. The transcription factor XBP1 is selectively required for eosinophil differentiation. Nat Immunol 2015; 16:829-37. [PMID: 26147683 PMCID: PMC4577297 DOI: 10.1038/ni.3225] [Citation(s) in RCA: 127] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2015] [Accepted: 06/05/2015] [Indexed: 12/11/2022]
Abstract
The transcription factor XBP1 has been linked to the development of highly secretory tissues such as plasma cells and Paneth cells, yet its function in granulocyte maturation has remained unknown. Here we discovered an unexpectedly selective and absolute requirement for XBP1 in eosinophil differentiation without an effect on the survival of basophils or neutrophils. Progenitors of myeloid cells and eosinophils selectively activated the endoribonuclease IRE1α and spliced Xbp1 mRNA without inducing parallel endoplasmic reticulum (ER) stress signaling pathways. Without XBP1, nascent eosinophils exhibited massive defects in the post-translational maturation of key granule proteins required for survival, and these unresolvable structural defects fed back to suppress critical aspects of the transcriptional developmental program. Hence, we present evidence that granulocyte subsets can be distinguished by their differential reliance on secretory-pathway homeostasis.
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Affiliation(s)
- Sarah E Bettigole
- 1] Program in Immunology, Harvard Medical School, Boston, Massachusetts, USA. [2] Department of Medicine, Weill Cornell Medical College, Cornell University, New York, New York, USA. [3] Sandra and Edward Meyer Cancer Center, Weill Cornell Medical College, New York, New York, USA
| | - Raphael Lis
- 1] Ansary Stem Cell Institute, Department of Genetic Medicine, and Howard Hughes Medical Institute, Weill Cornell Medical College, New York, New York, USA. [2] Ronald O. Perelman and Claudia Cohen Center for Reproductive Medicine, Weill Cornell Medical College, New York, New York, USA
| | - Stanley Adoro
- 1] Department of Medicine, Weill Cornell Medical College, Cornell University, New York, New York, USA. [2] Sandra and Edward Meyer Cancer Center, Weill Cornell Medical College, New York, New York, USA
| | - Ann-Hwee Lee
- Department of Pathology and Laboratory Medicine, Weill Cornell Medical College, Cornell University, New York, New York, USA
| | - Lisa A Spencer
- Department of Medicine, Division of Allergy and Inflammation, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts, USA
| | - Peter F Weller
- Department of Medicine, Division of Allergy and Inflammation, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts, USA
| | - Laurie H Glimcher
- 1] Department of Medicine, Weill Cornell Medical College, Cornell University, New York, New York, USA. [2] Sandra and Edward Meyer Cancer Center, Weill Cornell Medical College, New York, New York, USA
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355
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Hiramatsu N, Chiang WC, Kurt TD, Sigurdson CJ, Lin JH. Multiple Mechanisms of Unfolded Protein Response-Induced Cell Death. THE AMERICAN JOURNAL OF PATHOLOGY 2015; 185:1800-8. [PMID: 25956028 PMCID: PMC4484218 DOI: 10.1016/j.ajpath.2015.03.009] [Citation(s) in RCA: 122] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/12/2013] [Revised: 02/09/2015] [Accepted: 03/26/2015] [Indexed: 12/12/2022]
Abstract
Eukaryotic cells fold and assemble membrane and secreted proteins in the endoplasmic reticulum (ER), before delivery to other cellular compartments or the extracellular environment. Correctly folded proteins are released from the ER, and poorly folded proteins are retained until they achieve stable conformations; irreparably misfolded proteins are targeted for degradation. Diverse pathological insults, such as amino acid mutations, hypoxia, or infection, can overwhelm ER protein quality control, leading to misfolded protein buildup, causing ER stress. To cope with ER stress, eukaryotic cells activate the unfolded protein response (UPR) by increasing levels of ER protein-folding enzymes and chaperones, enhancing the degradation of misfolded proteins, and reducing protein translation. In mammalian cells, three ER transmembrane proteins, inositol-requiring enzyme-1 (IRE1; official name ERN1), PKR-like ER kinase (PERK; official name EIF2AK3), and activating transcription factor-6, control the UPR. The UPR signaling triggers a set of prodeath programs when the cells fail to successfully adapt to ER stress or restore homeostasis. ER stress and UPR signaling are implicated in the pathogenesis of diverse diseases, including neurodegeneration, cancer, diabetes, and inflammation. This review discusses the current understanding in both adaptive and apoptotic responses as well as the molecular mechanisms instigating apoptosis via IRE1 and PERK signaling. We also examine how IRE1 and PERK signaling may be differentially used during neurodegeneration arising in retinitis pigmentosa and prion infection.
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Affiliation(s)
- Nobuhiko Hiramatsu
- Department of Pathology, University of California-San Diego, La Jolla, California
| | - Wei-Chieh Chiang
- Department of Pathology, University of California-San Diego, La Jolla, California
| | - Timothy D Kurt
- Department of Pathology, University of California-San Diego, La Jolla, California
| | | | - Jonathan H Lin
- Department of Pathology, University of California-San Diego, La Jolla, California.
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356
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D’Osualdo A, Anania VG, Yu K, Lill JR, Kaufman RJ, Matsuzawa SI, Reed JC. Transcription Factor ATF4 Induces NLRP1 Inflammasome Expression during Endoplasmic Reticulum Stress. PLoS One 2015; 10:e0130635. [PMID: 26086088 PMCID: PMC4472728 DOI: 10.1371/journal.pone.0130635] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2015] [Accepted: 05/21/2015] [Indexed: 12/30/2022] Open
Abstract
Perturbation of endoplasmic reticulum (ER) homeostasis triggers the ER stress response (also known as Unfolded Protein Response), a hallmark of many pathological disorders. However the connection between ER stress and inflammation remains largely unexplored. Recent data suggest that ER stress controls the activity of inflammasomes, key signaling platforms that mediate innate immune responses. Here we report that expression of NLRP1, a core inflammasome component, is specifically up-regulated during severe ER stress conditions in human cell lines. Both IRE1α and PERK, but not the ATF6 pathway, modulate NLRP1 gene expression. Furthermore, using mutagenesis, chromatin immunoprecipitation and CRISPR-Cas9-mediated genome editing technology, we demonstrate that ATF4 transcription factor directly binds to NLRP1 promoter during ER stress. Although involved in different types of inflammatory responses, XBP-1 splicing was not required for NLRP1 induction. This study provides further evidence that links ER stress with innate
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Affiliation(s)
- Andrea D’Osualdo
- Cell Death and Survival Networks Program, Sanford-Burnham Medical Research Institute, La Jolla, California, United States of America
| | - Veronica G. Anania
- Department of Protein Chemistry, Genentech Inc, South San Francisco, California, United States of America
| | - Kebing Yu
- Department of Protein Chemistry, Genentech Inc, South San Francisco, California, United States of America
| | - Jennie R. Lill
- Department of Protein Chemistry, Genentech Inc, South San Francisco, California, United States of America
| | - Randal J. Kaufman
- Degenerative Diseases Research Program, Sanford-Burnham Medical Research Institute, La Jolla, California, United States of America
| | - Shu-ichi Matsuzawa
- Cell Death and Survival Networks Program, Sanford-Burnham Medical Research Institute, La Jolla, California, United States of America
- * E-mail: (JCR); (SM)
| | - John C. Reed
- Cell Death and Survival Networks Program, Sanford-Burnham Medical Research Institute, La Jolla, California, United States of America
- Pharma Research and Early Development (pRED), Roche, Basel, Switzerland
- * E-mail: (JCR); (SM)
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357
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Higgins R, Gendron JM, Rising L, Mak R, Webb K, Kaiser SE, Zuzow N, Riviere P, Yang B, Fenech E, Tang X, Lindsay SA, Christianson JC, Hampton RY, Wasserman SA, Bennett EJ. The Unfolded Protein Response Triggers Site-Specific Regulatory Ubiquitylation of 40S Ribosomal Proteins. Mol Cell 2015; 59:35-49. [PMID: 26051182 DOI: 10.1016/j.molcel.2015.04.026] [Citation(s) in RCA: 105] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2014] [Revised: 03/17/2015] [Accepted: 04/12/2015] [Indexed: 01/07/2023]
Abstract
Insults to ER homeostasis activate the unfolded protein response (UPR), which elevates protein folding and degradation capacity and attenuates protein synthesis. While a role for ubiquitin in regulating the degradation of misfolded ER-resident proteins is well described, ubiquitin-dependent regulation of translational reprogramming during the UPR remains uncharacterized. Using global quantitative ubiquitin proteomics, we identify evolutionarily conserved, site-specific regulatory ubiquitylation of 40S ribosomal proteins. We demonstrate that these events occur on assembled cytoplasmic ribosomes and are stimulated by both UPR activation and translation inhibition. We further show that ER stress-stimulated regulatory 40S ribosomal ubiquitylation occurs on a timescale similar to eIF2α phosphorylation, is dependent upon PERK signaling, and is required for optimal cell survival during chronic UPR activation. In total, these results reveal regulatory 40S ribosomal ubiquitylation as an important facet of eukaryotic translational control.
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Affiliation(s)
- Reneé Higgins
- Section of Cell and Developmental Biology, Division of Biological Sciences, University of California, San Diego, La Jolla, CA 92093, USA
| | - Joshua M Gendron
- Section of Cell and Developmental Biology, Division of Biological Sciences, University of California, San Diego, La Jolla, CA 92093, USA
| | - Lisa Rising
- Section of Cell and Developmental Biology, Division of Biological Sciences, University of California, San Diego, La Jolla, CA 92093, USA
| | - Raymond Mak
- Section of Cell and Developmental Biology, Division of Biological Sciences, University of California, San Diego, La Jolla, CA 92093, USA
| | - Kristofor Webb
- Section of Cell and Developmental Biology, Division of Biological Sciences, University of California, San Diego, La Jolla, CA 92093, USA
| | - Stephen E Kaiser
- Cancer Structural Biology, Oncology Medicinal Chemistry, Pfizer Worldwide Research and Development, 10770 Science Center Drive, San Diego, CA 92121, USA
| | - Nathan Zuzow
- Section of Cell and Developmental Biology, Division of Biological Sciences, University of California, San Diego, La Jolla, CA 92093, USA
| | - Paul Riviere
- Section of Cell and Developmental Biology, Division of Biological Sciences, University of California, San Diego, La Jolla, CA 92093, USA
| | - Bing Yang
- Section of Cell and Developmental Biology, Division of Biological Sciences, University of California, San Diego, La Jolla, CA 92093, USA
| | - Emma Fenech
- Ludwig Institute for Cancer Research, University of Oxford, ORCRB, Headington, Oxford OX3 7DQ, United Kingdom
| | - Xin Tang
- Section of Cell and Developmental Biology, Division of Biological Sciences, University of California, San Diego, La Jolla, CA 92093, USA
| | - Scott A Lindsay
- Section of Cell and Developmental Biology, Division of Biological Sciences, University of California, San Diego, La Jolla, CA 92093, USA
| | - John C Christianson
- Ludwig Institute for Cancer Research, University of Oxford, ORCRB, Headington, Oxford OX3 7DQ, United Kingdom
| | - Randolph Y Hampton
- Section of Cell and Developmental Biology, Division of Biological Sciences, University of California, San Diego, La Jolla, CA 92093, USA
| | - Steven A Wasserman
- Section of Cell and Developmental Biology, Division of Biological Sciences, University of California, San Diego, La Jolla, CA 92093, USA
| | - Eric J Bennett
- Section of Cell and Developmental Biology, Division of Biological Sciences, University of California, San Diego, La Jolla, CA 92093, USA
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358
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Kohl S, Zobor D, Chiang WC, Weisschuh N, Staller J, Gonzalez Menendez I, Chang S, Beck SC, Garcia Garrido M, Sothilingam V, Seeliger MW, Stanzial F, Benedicenti F, Inzana F, Héon E, Vincent A, Beis J, Strom TM, Rudolph G, Roosing S, Hollander AID, Cremers FPM, Lopez I, Ren H, Moore AT, Webster AR, Michaelides M, Koenekoop RK, Zrenner E, Kaufman RJ, Tsang SH, Wissinger B, Lin JH. Mutations in the unfolded protein response regulator ATF6 cause the cone dysfunction disorder achromatopsia. Nat Genet 2015; 47:757-65. [PMID: 26029869 DOI: 10.1038/ng.3319] [Citation(s) in RCA: 158] [Impact Index Per Article: 17.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2014] [Accepted: 05/04/2015] [Indexed: 01/10/2023]
Abstract
Achromatopsia (ACHM) is an autosomal recessive disorder characterized by color blindness, photophobia, nystagmus and severely reduced visual acuity. Using homozygosity mapping and whole-exome and candidate gene sequencing, we identified ten families carrying six homozygous and two compound-heterozygous mutations in the ATF6 gene (encoding activating transcription factor 6A), a key regulator of the unfolded protein response (UPR) and cellular endoplasmic reticulum (ER) homeostasis. Patients had evidence of foveal hypoplasia and disruption of the cone photoreceptor layer. The ACHM-associated ATF6 mutations attenuate ATF6 transcriptional activity in response to ER stress. Atf6(-/-) mice have normal retinal morphology and function at a young age but develop rod and cone dysfunction with increasing age. This new ACHM-related gene suggests a crucial and unexpected role for ATF6A in human foveal development and cone function and adds to the list of genes that, despite ubiquitous expression, when mutated can result in an isolated retinal photoreceptor phenotype.
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Affiliation(s)
- Susanne Kohl
- Institute for Ophthalmic Research, Centre for Ophthalmology, University of Tübingen, Tübingen, Germany
| | - Ditta Zobor
- Institute for Ophthalmic Research, Centre for Ophthalmology, University of Tübingen, Tübingen, Germany
| | - Wei-Chieh Chiang
- Department of Pathology, University of California, San Diego, La Jolla, California, USA
| | - Nicole Weisschuh
- Institute for Ophthalmic Research, Centre for Ophthalmology, University of Tübingen, Tübingen, Germany
| | - Jennifer Staller
- Institute for Ophthalmic Research, Centre for Ophthalmology, University of Tübingen, Tübingen, Germany
| | - Irene Gonzalez Menendez
- Institute for Ophthalmic Research, Centre for Ophthalmology, University of Tübingen, Tübingen, Germany
| | - Stanley Chang
- 1] Department of Ophthalmology, Columbia University, New York, New York, USA. [2] Edward Harkness Eye Institute, New York Presbyterian Hospital, New York, New York, USA
| | - Susanne C Beck
- Institute for Ophthalmic Research, Centre for Ophthalmology, University of Tübingen, Tübingen, Germany
| | - Marina Garcia Garrido
- Institute for Ophthalmic Research, Centre for Ophthalmology, University of Tübingen, Tübingen, Germany
| | - Vithiyanjali Sothilingam
- Institute for Ophthalmic Research, Centre for Ophthalmology, University of Tübingen, Tübingen, Germany
| | - Mathias W Seeliger
- Institute for Ophthalmic Research, Centre for Ophthalmology, University of Tübingen, Tübingen, Germany
| | - Franco Stanzial
- Clinical Genetics Service, Regional Hospital Bozen, Bozen, Italy
| | | | - Francesca Inzana
- Clinical Genetics Service, Regional Hospital Bozen, Bozen, Italy
| | - Elise Héon
- Department of Ophthalmology and Vision Sciences, Programme of Genetics and Genomic Medicine, The Hospital for Sick Children, University of Toronto, Toronto, Ontario, Canada
| | - Ajoy Vincent
- Department of Ophthalmology and Vision Sciences, Programme of Genetics and Genomic Medicine, The Hospital for Sick Children, University of Toronto, Toronto, Ontario, Canada
| | - Jill Beis
- Medical Genetics, IWK Health Centre, Halifax, Nova Scotia, Canada
| | - Tim M Strom
- 1] Institute of Human Genetics, Helmholtz Zentrum München, Neuherberg, Germany. [2] Institute of Human Genetics, Technische Universität München, Munich, Germany
| | - Günther Rudolph
- University Eye Hospital, Ludwig Maximilians University, Munich, Germany
| | - Susanne Roosing
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Anneke I den Hollander
- 1] Department of Human Genetics, Radboud University Medical Center, Nijmegen, the Netherlands. [2] Department of Ophthalmology, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Frans P M Cremers
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Irma Lopez
- McGill Ocular Genetics Centre, McGill University Health Centre, Montreal, Quebec, Canada
| | - Huanan Ren
- McGill Ocular Genetics Centre, McGill University Health Centre, Montreal, Quebec, Canada
| | - Anthony T Moore
- 1] University College London Institute of Ophthalmology, University College London, London, UK. [2] Moorfields Eye Hospital, London, UK. [3] Ophthalmology Department, University of California San Francisco Medical School, San Francisco, California, USA
| | - Andrew R Webster
- 1] University College London Institute of Ophthalmology, University College London, London, UK. [2] Moorfields Eye Hospital, London, UK
| | - Michel Michaelides
- 1] University College London Institute of Ophthalmology, University College London, London, UK. [2] Moorfields Eye Hospital, London, UK
| | - Robert K Koenekoop
- McGill Ocular Genetics Centre, McGill University Health Centre, Montreal, Quebec, Canada
| | - Eberhart Zrenner
- 1] Institute for Ophthalmic Research, Centre for Ophthalmology, University of Tübingen, Tübingen, Germany. [2] Werner Reichardt Center for Integrative Neuroscience, University of Tübingen, Tübingen, Germany
| | - Randal J Kaufman
- Degenerative Diseases Program, Sanford-Burnham Medical Research Institute, La Jolla, California, USA
| | - Stephen H Tsang
- 1] Department of Ophthalmology, Columbia University, New York, New York, USA. [2] Jonas Laboratory of Stem Cell and Regenerative Medicine, Columbia University, New York, New York, USA. [3] Brown Glaucoma Laboratory, Columbia University, New York, New York, USA. [4] Institute of Human Nutrition, Columbia University, New York, New York, USA. [5] Department of Pathology and Cell Biology, Columbia University, New York, New York, USA
| | - Bernd Wissinger
- Institute for Ophthalmic Research, Centre for Ophthalmology, University of Tübingen, Tübingen, Germany
| | - Jonathan H Lin
- 1] Department of Pathology, University of California, San Diego, La Jolla, California, USA. [2] Department of Ophthalmology, University of California, San Diego, La Jolla, California, USA
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359
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Ramming T, Okumura M, Kanemura S, Baday S, Birk J, Moes S, Spiess M, Jenö P, Bernèche S, Inaba K, Appenzeller-Herzog C. A PDI-catalyzed thiol-disulfide switch regulates the production of hydrogen peroxide by human Ero1. Free Radic Biol Med 2015; 83:361-72. [PMID: 25697776 DOI: 10.1016/j.freeradbiomed.2015.02.011] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/15/2014] [Revised: 02/02/2015] [Accepted: 02/06/2015] [Indexed: 12/16/2022]
Abstract
Oxidative folding in the endoplasmic reticulum (ER) involves ER oxidoreductin 1 (Ero1)-mediated disulfide formation in protein disulfide isomerase (PDI). In this process, Ero1 consumes oxygen (O2) and releases hydrogen peroxide (H2O2), but none of the published Ero1 crystal structures reveal any potential pathway for entry and exit of these reactants. We report that additional mutation of the Cys(208)-Cys(241) disulfide in hyperactive Ero1α (Ero1α-C104A/C131A) potentiates H2O2 production, ER oxidation, and cell toxicity. This disulfide clamps two helices that seal the flavin cofactor where O2 is reduced to H2O2. Through its carboxyterminal active site, PDI unlocks this seal by forming a Cys(208)/Cys(241)-dependent mixed-disulfide complex with Ero1α. The H2O2-detoxifying glutathione peroxidase 8 also binds to the Cys(208)/Cys(241) loop region. Supported by O2 diffusion simulations, these data describe the first enzymatically controlled O2 access into a flavoprotein active site, provide molecular-level understanding of Ero1α regulation and H2O2 production/detoxification, and establish the deleterious consequences of constitutive Ero1 activity.
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Affiliation(s)
- Thomas Ramming
- Division of Molecular & Systems Toxicology, Department of Pharmaceutical Sciences, University of Basel, 4056 Basel, Switzerland
| | - Masaki Okumura
- Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Sendai 980-8577, Japan
| | - Shingo Kanemura
- Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Sendai 980-8577, Japan
| | - Sefer Baday
- Swiss Institutes of Bioinformatics, University of Basel, 4056 Basel, Switzerland; Biozentrum, University of Basel, 4056 Basel, Switzerland
| | - Julia Birk
- Division of Molecular & Systems Toxicology, Department of Pharmaceutical Sciences, University of Basel, 4056 Basel, Switzerland
| | - Suzette Moes
- Biozentrum, University of Basel, 4056 Basel, Switzerland
| | - Martin Spiess
- Biozentrum, University of Basel, 4056 Basel, Switzerland
| | - Paul Jenö
- Biozentrum, University of Basel, 4056 Basel, Switzerland
| | - Simon Bernèche
- Swiss Institutes of Bioinformatics, University of Basel, 4056 Basel, Switzerland; Biozentrum, University of Basel, 4056 Basel, Switzerland
| | - Kenji Inaba
- Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Sendai 980-8577, Japan
| | - Christian Appenzeller-Herzog
- Division of Molecular & Systems Toxicology, Department of Pharmaceutical Sciences, University of Basel, 4056 Basel, Switzerland.
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360
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Chen JJ, Genereux JC, Wiseman RL. Endoplasmic reticulum quality control and systemic amyloid disease: Impacting protein stability from the inside out. IUBMB Life 2015; 67:404-13. [PMID: 26018985 DOI: 10.1002/iub.1386] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2015] [Accepted: 04/27/2015] [Indexed: 11/11/2022]
Abstract
The endoplasmic reticulum (ER) is responsible for regulating proteome integrity throughout the secretory pathway. The ER protects downstream secretory environments such as the extracellular space by partitioning proteins between ER protein folding, trafficking, and degradation pathways in a process called ER quality control. In this process, ER quality control factors identify misfolded, aggregation-prone protein conformations and direct them toward ER protein folding or degradation, reducing their secretion to the extracellular space where they could further misfold or aggregate into proteotoxic conformations. Despite the general efficiency of ER quality control, many human diseases, such as the systemic amyloidoses, involve aggregation of destabilized, aggregation-prone proteins in the extracellular space. A common feature for all systemic amyloid diseases is the ability for amyloidogenic proteins to evade ER quality control and be efficiently secreted. The efficient secretion of these amyloidogenic proteins increases their serum concentrations available for the distal proteotoxic aggregation characteristic of these diseases. This indicates that ER quality control, and the regulation thereof, is a critical determinant in defining the onset and pathology of systemic amyloid diseases. Here, we discuss the pathologic and potential therapeutic relationship between ER quality control, protein secretion, and distal deposition of amyloidogenic proteins involved in systemic amyloid diseases. Furthermore, we present evidence that the unfolded protein response, the stress-responsive signaling pathway that regulates ER quality control, is involved in the pathogenesis of systemic amyloid diseases and represents a promising emerging therapeutic target to intervene in this class of human disease.
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Affiliation(s)
- John J Chen
- Department of Molecular and Experimental Medicine, The Scripps Research Institute, La Jolla, CA, USA.,Department of Chemical Physiology, The Scripps Research Institute, La Jolla, CA, USA
| | - Joseph C Genereux
- Department of Molecular and Experimental Medicine, The Scripps Research Institute, La Jolla, CA, USA.,Department of Chemical Physiology, The Scripps Research Institute, La Jolla, CA, USA
| | - R Luke Wiseman
- Department of Molecular and Experimental Medicine, The Scripps Research Institute, La Jolla, CA, USA.,Department of Chemical Physiology, The Scripps Research Institute, La Jolla, CA, USA
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361
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Chevet E, Hetz C, Samali A. Endoplasmic reticulum stress-activated cell reprogramming in oncogenesis. Cancer Discov 2015; 5:586-97. [PMID: 25977222 DOI: 10.1158/2159-8290.cd-14-1490] [Citation(s) in RCA: 271] [Impact Index Per Article: 30.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2014] [Accepted: 04/28/2015] [Indexed: 12/29/2022]
Abstract
UNLABELLED Stress induced by the accumulation of unfolded proteins in the endoplasmic reticulum (ER) is observed in many human diseases, including cancers. Cellular adaptation to ER stress is mediated by the unfolded protein response (UPR), which aims at restoring ER homeostasis. The UPR has emerged as a major pathway in remodeling cancer gene expression, thereby either preventing cell transformation or providing an advantage to transformed cells. UPR sensors are highly regulated by the formation of dynamic protein scaffolds, leading to integrated reprogramming of the cells. Herein, we describe the regulatory mechanisms underlying UPR signaling upon cell intrinsic or extrinsic challenges, and how they engage cell transformation programs and/or provide advantages to cancer cells, leading to enhanced aggressiveness or chemoresistance. We discuss the emerging cross-talk between the UPR and related metabolic processes to ensure maintenance of protein homeostasis and its impact on cell transformation and tumor growth. SIGNIFICANCE ER stress signaling is dysregulated in many forms of cancer and contributes to tumor growth as a survival factor, in addition to modulating other disease-associated processes, including cell migration, cell transformation, and angiogenesis. Evidence for targeting the ER stress signaling pathway as an anticancer strategy is compelling, and novel agents that selectively inhibit the UPR have demonstrated preliminary evidence of preclinical efficacy with an acceptable safety profile.
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Affiliation(s)
- Eric Chevet
- Oncogenesis, Stress, Cancer, University of Rennes, Rennes, France. Centre de Lutte Contre le Cancer Eugène Marquis, Rennes, France.
| | - Claudio Hetz
- Biomedical Neuroscience Institute, Faculty of Medicine, University of Chile, Santiago, Chile. Institute of Biomedical Sciences, Center for Molecular Studies of the Cell, Santiago, Chile. Department of Immunology and Infectious Diseases, Harvard School of Public Health, Boston, Massachusetts.
| | - Afshin Samali
- Apoptosis Research Centre, School of Natural Sciences, National University of Ireland Galway, Galway, Ireland.
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362
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Dufey E, Urra H, Hetz C. ER proteostasis addiction in cancer biology: Novel concepts. Semin Cancer Biol 2015; 33:40-7. [PMID: 25931388 DOI: 10.1016/j.semcancer.2015.04.003] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2014] [Revised: 04/15/2015] [Accepted: 04/20/2015] [Indexed: 01/22/2023]
Abstract
Endoplasmic reticulum (ER) stress is generated by various physiological and pathological conditions that induce an accumulation of misfolded proteins in its lumen. ER stress activates the unfolded protein response (UPR), an adaptive reaction to cope with protein misfolding to and restore proteostasis. However, chronic ER stress results in apoptosis. In solid tumors, the UPR mediates adaptation to various environmental stressors, including hypoxia, low in pH and low nutrients availability, driving positive selection. Recent findings support the concept that UPR signaling also contributes to other relevant cancer-related event that may not be related to ER stress, including angiogenesis, genomic instability, metastasis and immunomodulation. In this article, we overview novel discoveries highlighting the impact of the UPR to different aspects of cancer biology beyond its known role as a survival factor to the hypoxic environment observed in solid tumors.
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Affiliation(s)
- Estefanie Dufey
- Biomedical Neuroscience Institute, Faculty of Medicine, University of Chile, Santiago, Chile; Program of Cellular and Molecular Biology, Institute of Biomedical Sciences, Center for Molecular Studies of the Cell, Faculty of Medicine, University of Chile, Santiago, Chile
| | - Hery Urra
- Biomedical Neuroscience Institute, Faculty of Medicine, University of Chile, Santiago, Chile; Program of Cellular and Molecular Biology, Institute of Biomedical Sciences, Center for Molecular Studies of the Cell, Faculty of Medicine, University of Chile, Santiago, Chile
| | - Claudio Hetz
- Biomedical Neuroscience Institute, Faculty of Medicine, University of Chile, Santiago, Chile; Program of Cellular and Molecular Biology, Institute of Biomedical Sciences, Center for Molecular Studies of the Cell, Faculty of Medicine, University of Chile, Santiago, Chile; Department of Immunology and Infectious Diseases, Harvard School of Public Health, Boston, MA 02115, USA.
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363
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Karam R, Lou CH, Kroeger H, Huang L, Lin JH, Wilkinson MF. The unfolded protein response is shaped by the NMD pathway. EMBO Rep 2015; 16:599-609. [PMID: 25807986 DOI: 10.15252/embr.201439696] [Citation(s) in RCA: 96] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2014] [Accepted: 02/24/2015] [Indexed: 12/15/2022] Open
Abstract
Endoplasmic reticulum (ER) stress induces the unfolded protein response (UPR), an essential adaptive intracellular pathway that relieves the stress. Although the UPR is an evolutionarily conserved and beneficial pathway, its chronic activation contributes to the pathogenesis of a wide variety of human disorders. The fidelity of UPR activation must thus be tightly regulated to prevent inappropriate signaling. The nonsense-mediated RNA decay (NMD) pathway has long been known to function in RNA quality control, rapidly degrading aberrant mRNAs, and has been suggested to regulate subsets of normal mRNAs. Here, we report that the NMD pathway regulates the UPR. NMD increases the threshold for triggering the UPR in vitro and in vivo, thereby preventing UPR activation in response to normally innocuous levels of ER stress. NMD also promotes the timely termination of the UPR. We demonstrate that NMD directly targets the mRNAs encoding several UPR components, including the highly conserved UPR sensor, IRE1α, whose NMD-dependent degradation partly underpins this process. Our work not only sheds light on UPR regulation, but demonstrates the physiological relevance of NMD's ability to regulate normal mRNAs.
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Affiliation(s)
- Rachid Karam
- Department of Reproductive Medicine, School of Medicine, University of California San Diego, La Jolla, CA, USA
| | - Chih-Hong Lou
- Department of Reproductive Medicine, School of Medicine, University of California San Diego, La Jolla, CA, USA
| | - Heike Kroeger
- Department of Pathology, School of Medicine, University of California San Diego, La Jolla, CA, USA
| | - Lulu Huang
- Department of Reproductive Medicine, School of Medicine, University of California San Diego, La Jolla, CA, USA
| | - Jonathan H Lin
- Department of Pathology, School of Medicine, University of California San Diego, La Jolla, CA, USA
| | - Miles F Wilkinson
- Department of Reproductive Medicine, School of Medicine, University of California San Diego, La Jolla, CA, USA Institute of Genomic Medicine, University of California San Diego, La Jolla, CA, USA
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364
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Maurel M, McGrath EP, Mnich K, Healy S, Chevet E, Samali A. Controlling the unfolded protein response-mediated life and death decisions in cancer. Semin Cancer Biol 2015; 33:57-66. [PMID: 25814342 DOI: 10.1016/j.semcancer.2015.03.003] [Citation(s) in RCA: 74] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2014] [Revised: 03/14/2015] [Accepted: 03/16/2015] [Indexed: 12/20/2022]
Abstract
Cancer cells are exposed to intrinsic (oncogene) or extrinsic (microenvironmental) challenges, leading to activation of stress response pathways. The unfolded protein response (UPR) is the cellular response to endoplasmic reticulum (ER) stress and plays a pivotal role in tumor development. Depending on ER stress intensity and duration, the UPR is either pro-survival to preserve ER homeostasis or pro-death if the stress cannot be resolved. On one hand, the adaptive arm of the UPR is essential for cancer cells to survive the harsh conditions they are facing, and on the other hand, cancer cells have evolved mechanisms to bypass ER stress-induced cell death, thereby conferring them with a selective advantage for malignant transformation. Therefore, the mechanisms involved in the balance between survival and death outcomes of the UPR may be exploited as therapeutic tools to treat cancer.
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Affiliation(s)
- Marion Maurel
- Apoptosis Research Centre, National University of Ireland, Galway, Ireland; Centre de Lutte Contre le Cancer Eugène Marquis, 35000 Rennes, France
| | - Eoghan P McGrath
- Apoptosis Research Centre, National University of Ireland, Galway, Ireland
| | - Katarzyna Mnich
- Apoptosis Research Centre, National University of Ireland, Galway, Ireland
| | - Sandra Healy
- Apoptosis Research Centre, National University of Ireland, Galway, Ireland
| | - Eric Chevet
- Inserm U1052, F-33000, University of Bordeaux, Bordeaux, France; Centre de Lutte Contre le Cancer Eugène Marquis, 35000 Rennes, France
| | - Afshin Samali
- Apoptosis Research Centre, National University of Ireland, Galway, Ireland.
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365
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Vacaru AM, Di Narzo AF, Howarth DL, Tsedensodnom O, Imrie D, Cinaroglu A, Amin S, Hao K, Sadler KC. Molecularly defined unfolded protein response subclasses have distinct correlations with fatty liver disease in zebrafish. Dis Model Mech 2015; 7:823-35. [PMID: 24973751 PMCID: PMC4073272 DOI: 10.1242/dmm.014472] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
The unfolded protein response (UPR) is a complex network of sensors and target genes that ensure efficient folding of secretory proteins in the endoplasmic reticulum (ER). UPR activation is mediated by three main sensors, which regulate the expression of hundreds of targets. UPR activation can result in outcomes ranging from enhanced cellular function to cell dysfunction and cell death. How this pathway causes such different outcomes is unknown. Fatty liver disease (steatosis) is associated with markers of UPR activation and robust UPR induction can cause steatosis; however, in other cases, UPR activation can protect against this disease. By assessing the magnitude of activation of UPR sensors and target genes in the liver of zebrafish larvae exposed to three commonly used ER stressors (tunicamycin, thapsigargin and Brefeldin A), we have identified distinct combinations of UPR sensors and targets (i.e. subclasses) activated by each stressor. We found that only the UPR subclass characterized by maximal induction of UPR target genes, which we term a stressed-UPR, induced steatosis. Principal component analysis demonstrated a significant positive association between UPR target gene induction and steatosis. The same principal component analysis showed significant correlation with steatosis in samples from patients with fatty liver disease. We demonstrate that an adaptive UPR induced by a short exposure to thapsigargin prior to challenging with tunicamycin reduced both the induction of a stressed UPR and steatosis incidence. We conclude that a stressed UPR causes steatosis and an adaptive UPR prevents it, demonstrating that this pathway plays dichotomous roles in fatty liver disease.
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Affiliation(s)
- Ana M Vacaru
- Department of Medicine/Division of Liver Diseases, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA. Department of Developmental and Regenerative Biology, Icahn School of Medicine at Mount Sinai, Box 1020, 1 Gustave L. Levy Place, New York, NY 10029, USA
| | - Antonio Fabio Di Narzo
- Department of Genetics and Genomic Sciences and Icahn Institute for Genomics and Multiscale Biology, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Deanna L Howarth
- Department of Medicine/Division of Liver Diseases, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA. Department of Developmental and Regenerative Biology, Icahn School of Medicine at Mount Sinai, Box 1020, 1 Gustave L. Levy Place, New York, NY 10029, USA
| | - Orkhontuya Tsedensodnom
- Department of Medicine/Division of Liver Diseases, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA. Department of Developmental and Regenerative Biology, Icahn School of Medicine at Mount Sinai, Box 1020, 1 Gustave L. Levy Place, New York, NY 10029, USA
| | - Dru Imrie
- Department of Medicine/Division of Liver Diseases, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA. Department of Developmental and Regenerative Biology, Icahn School of Medicine at Mount Sinai, Box 1020, 1 Gustave L. Levy Place, New York, NY 10029, USA
| | - Ayca Cinaroglu
- Department of Medicine/Division of Liver Diseases, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA. Department of Developmental and Regenerative Biology, Icahn School of Medicine at Mount Sinai, Box 1020, 1 Gustave L. Levy Place, New York, NY 10029, USA
| | - Salma Amin
- Department of Medicine/Division of Liver Diseases, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA. Department of Developmental and Regenerative Biology, Icahn School of Medicine at Mount Sinai, Box 1020, 1 Gustave L. Levy Place, New York, NY 10029, USA
| | - Ke Hao
- Department of Genetics and Genomic Sciences and Icahn Institute for Genomics and Multiscale Biology, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Kirsten C Sadler
- Department of Medicine/Division of Liver Diseases, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA. Department of Developmental and Regenerative Biology, Icahn School of Medicine at Mount Sinai, Box 1020, 1 Gustave L. Levy Place, New York, NY 10029, USA. Graduate School of Biomedical Sciences, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA.
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366
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Schinzel R, Dillin A. Endocrine aspects of organelle stress—cell non-autonomous signaling of mitochondria and the ER. Curr Opin Cell Biol 2015; 33:102-10. [PMID: 25677685 DOI: 10.1016/j.ceb.2015.01.006] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2015] [Accepted: 01/23/2015] [Indexed: 12/12/2022]
Abstract
Organisms have to cope with an unpredictable and dynamic environment. It is crucial for any living being to respond to these changes by buffering the effects on cellular homeostasis. Failure to appropriately respond to stress can have severe consequences for health and survival. Eukaryotic cells possess several organelle-specific stress responses to cope with this challenge. Besides their central role in stress resistance, these pathways have also been shown to be important in the regulation of proteome maintenance, development and longevity. Intriguingly, many of these effects seem to be controlled by only a subset of cells implying a systemic regulation in a cell non-autonomous manner. The understanding of the nature of this stress communication across tissues, its mechanisms and impact, will be paramount in understanding disease etiology and the development of therapeutic strategies.
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Affiliation(s)
- Robert Schinzel
- Department of Molecular and Cell Biology, The University of California, Berkeley, Li Ka Shing Center for Biomedical and Health Sciences, USA
| | - Andrew Dillin
- Department of Molecular and Cell Biology, The University of California, Berkeley, Li Ka Shing Center for Biomedical and Health Sciences, USA; Howard Hughes Medical Institute, The University of California, Berkeley, USA.
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367
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Walter F, Schmid J, Düssmann H, Concannon CG, Prehn JHM. Imaging of single cell responses to ER stress indicates that the relative dynamics of IRE1/XBP1 and PERK/ATF4 signalling rather than a switch between signalling branches determine cell survival. Cell Death Differ 2015; 22:1502-16. [PMID: 25633195 DOI: 10.1038/cdd.2014.241] [Citation(s) in RCA: 91] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2014] [Accepted: 12/15/2014] [Indexed: 12/18/2022] Open
Abstract
An accumulation of misfolded proteins in the endoplasmic reticulum (ER) triggers the unfolded protein response (UPR) mediated via the activation of three transmembrane proteins IRE1, PERK and ATF6. Signalling through these proteins is aimed at enhancing the ER folding capacity and reducing the folding load. If these processes fail to re-establish protein homeostasis within the ER, then cell death prevails via apoptosis. How the shift from pro-survival to pro-apoptotic signalling is regulated remains unclear with both IRE1 and PERK signalling associated with pro-survival as well as pro-apoptotic signalling. To investigate the temporal activation of IRE1 and PERK in live cells and their relationship to cellular fate, we devised single cell reporters for both ER stress signalling branches. SH-SY5Y neural cells stably expressing these fluorescent protein reporter constructs to monitor IRE1-splicing activity and PERK-mediated ATF4-translation were imaged using single cell and high content time lapse live cell microscopy. We could correlate an early onset and attenuation of XBP1 splicing in the IRE1-reporter cells as cytoprotective. Indeed, silencing of IRE1 expression using shRNA inhibited splicing of XBP1 resulting in an early onset of cell death. In contrast, in the PERK-reporter cells, we observed that a slow rate of ATF4-translation and late re-initiation of general translation coincided with cells which were resistant to ER stress-induced cell death. Interestingly, whereas silencing of PERK did not affect overall levels of cell death in response to ER stress, it did increase sensitivity to ER stressors at early time points following treatment. Our results suggest that apoptosis activation in response to ER stress is not caused by a preferential activation of a single UPR branch, or by a switch from one branch to the other. Rather, our data indicated that the relative timing of IRE1 and PERK signalling determines the shift from cell survival to apoptosis.
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Affiliation(s)
- F Walter
- Centre for Systems Medicine and Department of Physiology and Medical Physics, Royal College of Surgeons in Ireland, 123 St Stephen's Green, Dublin 2, Ireland
| | - J Schmid
- Centre for Systems Medicine and Department of Physiology and Medical Physics, Royal College of Surgeons in Ireland, 123 St Stephen's Green, Dublin 2, Ireland
| | - H Düssmann
- Centre for Systems Medicine and Department of Physiology and Medical Physics, Royal College of Surgeons in Ireland, 123 St Stephen's Green, Dublin 2, Ireland
| | - C G Concannon
- Centre for Systems Medicine and Department of Physiology and Medical Physics, Royal College of Surgeons in Ireland, 123 St Stephen's Green, Dublin 2, Ireland
| | - J H M Prehn
- Centre for Systems Medicine and Department of Physiology and Medical Physics, Royal College of Surgeons in Ireland, 123 St Stephen's Green, Dublin 2, Ireland
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368
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Lhomond S, Pallares N, Barroso K, Schmit K, Dejeans N, Fazli H, Taouji S, Patterson JB, Chevet E. Adaptation of the secretory pathway in cancer through IRE1 signaling. Methods Mol Biol 2015; 1292:177-94. [PMID: 25804756 DOI: 10.1007/978-1-4939-2522-3_13] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The unfolded protein response (UPR) was originally identified as a signaling network coordinating adaptive and apoptotic responses to accumulation of unfolded proteins in the endoplasmic reticulum (ER). More recent work has shown that UPR signaling can be triggered by a multitude of cellular events and that the UPR plays a critical role in the prevention of cell transformation but also in tumor development. This has been particularly well illustrated with studies on one of the three major ER stress sensors, IRE1. This ER resident type I transmembrane protein senses luminal ER stress and transduce signals through its cytosolic RNase activity. IRE1 signaling has been shown to contribute to the progression of solid tumors through pro-angiogenic mechanisms. Herein, we expose the methodologies for investigating IRE1 signaling in tumor cells and in tumors. Moreover, we show that selective pharmacological inhibition of IRE1 RNase activity sensitizes tumor cells to ER stress.
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Affiliation(s)
- Stéphanie Lhomond
- Inserm, U1053, Université de Bordeaux, 146 rue Léo Saignat, 33000, Bordeaux, France
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369
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Cho Y, Baranczak A, Helmke S, Teruya S, Horn EM, Maurer MS, Kelly JW. Personalized medicine approach for optimizing the dose of tafamidis to potentially ameliorate wild-type transthyretin amyloidosis (cardiomyopathy). Amyloid 2015; 22:175-80. [PMID: 26193961 PMCID: PMC4549186 DOI: 10.3109/13506129.2015.1063485] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Placebo-controlled clinical trials are useful for identifying the dose of a drug candidate that produces a meaningful clinical response in a patient population. Currently, Pfizer, Inc. is enrolling a 400-person clinical trial to test the efficacy of 20 or 80 mg of tafamidis to ameliorate transthyretin (TTR)-associated cardiomyopathy using clinical endpoints. Herein, we provide guidance for how to optimize the dose of tafamidis for each WT TTR cardiomyopathy patient using its mechanism of action as the key readout, i.e. we identify the dose of tafamidis that maximally kinetically stabilizes TTR in the blood. Tetramer dissociation is rate limiting for TTR aggregation, which appears to drive the pathology of the TTR amyloidoses. Hence, we measure the TTR tetramer dissociation rate (kinetic stability) in the patient's plasma as a function of tafamidis dose to optimize the dose employed to maximize kinetic stability. Historical data tell us that a subset of patients exhibiting higher tafamidis plasma concentrations are maximally kinetically stabilized at the 20-mg tafamidis dose, whereas the patient studied herein required a 60 mg once daily dose to achieve maximum kinetic stabilization. We anticipate that establishing the dose of tafamidis that achieves maximal TTR kinetic stabilization will translate into a maximal clinical effect, but that remains to be demonstrated.
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370
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Pluquet O, Pourtier A, Abbadie C. The unfolded protein response and cellular senescence. A review in the theme: cellular mechanisms of endoplasmic reticulum stress signaling in health and disease. Am J Physiol Cell Physiol 2014; 308:C415-25. [PMID: 25540175 DOI: 10.1152/ajpcell.00334.2014] [Citation(s) in RCA: 199] [Impact Index Per Article: 19.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The endoplasmic reticulum (ER) is a multifunctional organelle critical for the proper folding and assembly of secreted and transmembrane proteins. Perturbations of ER functions cause ER stress, which activates a coordinated system of transcriptional and translational controls called the unfolded protein response (UPR), to cope with accumulation of misfolded proteins and proteotoxicity. It results in ER homeostasis restoration or in cell death. Senescence is a complex cell phenotype induced by several stresses such as telomere attrition, DNA damage, oxidative stress, and activation of some oncogenes. It is mainly characterized by a cell enlargement, a permanent cell-cycle arrest, and the production of a secretome enriched in proinflammatory cytokines and components of the extracellular matrix. Senescent cells accumulate with age in tissues and are suspected to play a role in age-associated diseases. Since senescence is a stress response, the question arises of whether an ER stress could occur concomitantly with senescence and participate in the onset or maintenance of the senescent features. Here, we described the interconnections between the UPR signaling and the different aspects of the cellular senescence programs and discuss the implication of UPR modulations in this context.
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Affiliation(s)
- Olivier Pluquet
- Centre National de la Recherche Scientifique, UMR8161, Institut de Biologie de Lille, Lille, France; Université Lille 1 Sciences et Techniques, Villeneuve d'Ascq, France; Université Lille 2 Droit et Santé, Lille, France; and Institut Pasteur de Lille, Lille, France
| | - Albin Pourtier
- Centre National de la Recherche Scientifique, UMR8161, Institut de Biologie de Lille, Lille, France; Université Lille 1 Sciences et Techniques, Villeneuve d'Ascq, France; Université Lille 2 Droit et Santé, Lille, France; and Institut Pasteur de Lille, Lille, France
| | - Corinne Abbadie
- Centre National de la Recherche Scientifique, UMR8161, Institut de Biologie de Lille, Lille, France; Université Lille 1 Sciences et Techniques, Villeneuve d'Ascq, France; Université Lille 2 Droit et Santé, Lille, France; and Institut Pasteur de Lille, Lille, France
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371
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Emerging functions of the unfolded protein response in immunity. Nat Immunol 2014; 15:910-9. [PMID: 25232821 DOI: 10.1038/ni.2991] [Citation(s) in RCA: 170] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2014] [Accepted: 08/18/2014] [Indexed: 12/14/2022]
Abstract
The unfolded protein response (UPR) has traditionally been viewed as an adaptive response triggered by the accumulation of unfolded proteins in the endoplasmic reticulum (ER) and aimed at restoring ER function. The UPR can also be an anticipatory response that is activated well before the disruption of protein homeostasis. UPR signaling intersects at many levels with the innate and adaptive immune responses. In some types of cells of the immune system, such as dendritic cells (DCs) and B cells, particular sensors that detect the UPR seem to be constitutively active in the absence of induction of the traditional UPR gene program and are necessary for antigen presentation and immunoglobulin synthesis. The UPR also influences signaling via Toll-like receptors (TLRs) and activation of the transcription factor NF-κB, and some pathogens subvert the UPR. This Review summarizes these emerging noncanonical functions of the UPR in immunity.
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372
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Armengol S, Arretxe E, Enzunza L, Mula S, Ochoa B, Chico Y, Martínez MJ. The promoter of cell growth- and RNA protection-associated SND1 gene is activated by endoplasmic reticulum stress in human hepatoma cells. BMC BIOCHEMISTRY 2014; 15:25. [PMID: 25494629 PMCID: PMC4266219 DOI: 10.1186/s12858-014-0025-2] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/06/2014] [Accepted: 11/26/2014] [Indexed: 12/15/2022]
Abstract
Background Staphyloccocal nuclease domain-containing protein 1 (SND1) is involved in the regulation of gene expression and RNA protection. While numerous studies have established that SND1 protein expression is modulated by cellular stresses associated with tumor growth, hypoxia, inflammation, heat-shock and oxidative conditions, little is known about the factors responsible for SND1 expression. Here, we have approached this question by analyzing the transcriptional response of human SND1 gene to pharmacological endoplasmic reticulum (ER) stress in liver cancer cells. Results We provide first evidence that SND1 promoter activity is increased in human liver cancer cells upon exposure to thapsigargin or tunicamycin or by ectopic expression of ATF6, a crucial transcription factor in the unfolded protein response triggered by ER stress. Deletion analysis of the 5’-flanking region of SND1 promoter identified maximal activation in fragment (-934, +221), which contains most of the predicted ER stress response elements in proximal promoter. Quantitative real-time PCR revealed a near 3 fold increase in SND1 mRNA expression by either of the stress-inducers; whereas SND1 protein was maximally upregulated (3.4-fold) in cells exposed to tunicamycin, a protein glycosylation inhibitor. Conclusion Promoter activity of the cell growth- and RNA-protection associated SND1 gene is up-regulated by ER stress in human hepatoma cells.
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Affiliation(s)
| | | | | | | | | | | | - María José Martínez
- Department of Physiology, Faculty of Medicine and Dentistry, University of the Basque Country UPV/EHU, Barrio Sarriena s/n, Leioa, 48940, Spain.
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373
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Abstract
Immune responses occur in the midst of a variety of cellular stresses that can severely perturb endoplasmic reticulum (ER) function. The unfolded protein response is a three-pronged signaling axis dedicated to preserving ER homeostasis. In this review, we highlight many important and emerging functional roles for ER stress in immunity, focusing on how the bidirectional cross talk between immunological processes and basic cell biology leads to pleiotropic signaling outcomes and enhanced sensitivity to inflammatory stimuli. We also discuss how dysregulated ER stress responses can provoke many diseases, including autoimmunity, firmly positioning the unfolded protein response as a major therapeutic target in human disease.
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Affiliation(s)
- Sarah E Bettigole
- Department of Medicine, Weill Cornell Medical College, New York, NY 10065; ,
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374
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Buck TM, Brodsky JL. Escaping the endoplasmic reticulum: why does a molecular chaperone leave home for greener pastures? EMBO J 2014; 34:1-3. [PMID: 25425576 DOI: 10.15252/embj.201490462] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Affiliation(s)
- Teresa M Buck
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA, USA
| | - Jeffrey L Brodsky
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA, USA
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375
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Chen JJ, Genereux JC, Qu S, Hulleman JD, Shoulders MD, Wiseman RL. ATF6 activation reduces the secretion and extracellular aggregation of destabilized variants of an amyloidogenic protein. CHEMISTRY & BIOLOGY 2014; 21:1564-74. [PMID: 25444553 PMCID: PMC4254654 DOI: 10.1016/j.chembiol.2014.09.009] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/02/2014] [Revised: 08/30/2014] [Accepted: 09/08/2014] [Indexed: 12/19/2022]
Abstract
Systemic amyloidoses result from the aberrant secretion of destabilized, amyloidogenic proteins to the serum where they aggregate into proteotoxic soluble aggregates and amyloid fibrils. Few therapeutic approaches exist to attenuate extracellular pathologic aggregation of amyloidogenic proteins, necessitating the development of new strategies to intervene in these devastating disorders. We show that stress-independent activation of the Unfolded Protein Response-associated transcription factor ATF6 increases ER quality control stringency for the amyloidogenic protein transthyretin (TTR), preferentially reducing secretion of disease-associated TTR variants to an extent corresponding to the variants' destabilization of the TTR tetramer. This decrease in destabilized TTR variant secretion attenuates extracellular, concentration-dependent aggregation of amyloidogenic TTRs into soluble aggregates commonly associated with proteotoxicity in disease. Collectively, our results indicate that increasing ER quality control stringency through ATF6 activation is a strategy to attenuate pathologic aggregation of a destabilized, amyloidogenic protein, revealing a potential approach to intervene in systemic amyloid disease pathology.
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Affiliation(s)
- John J Chen
- Department of Molecular and Experimental Medicine and Department of Chemical Physiology, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Joseph C Genereux
- Department of Molecular and Experimental Medicine and Department of Chemical Physiology, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Song Qu
- Department of Molecular and Experimental Medicine and Department of Chemical Physiology, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - John D Hulleman
- Department of Molecular and Experimental Medicine and Department of Chemical Physiology, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Matthew D Shoulders
- Department of Molecular and Experimental Medicine and Department of Chemical Physiology, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - R Luke Wiseman
- Department of Molecular and Experimental Medicine and Department of Chemical Physiology, The Scripps Research Institute, La Jolla, CA 92037, USA.
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376
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Raina K, Noblin DJ, Serebrenik YV, Adams A, Zhao C, Crews CM. Targeted protein destabilization reveals an estrogen-mediated ER stress response. Nat Chem Biol 2014; 10:957-62. [PMID: 25242550 PMCID: PMC4324732 DOI: 10.1038/nchembio.1638] [Citation(s) in RCA: 63] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2014] [Accepted: 08/14/2014] [Indexed: 12/16/2022]
Abstract
Accumulation of unfolded proteins within the endoplasmic reticulum (ER) of eukaryotic cells leads to an unfolded protein response (UPR) that either restores homeostasis or commits the cells to apoptosis. Tools traditionally used to study the UPR are proapoptotic and thus confound analysis of long-term cellular responses to ER stress. Here, we describe an ER-localized HaloTag (ERHT) protein that can be conditionally destabilized using a small-molecule hydrophobic tag (HyT36). Treatment of ERHT-expressing cells with HyT36 induces acute, resolvable ER stress that results in transient UPR activation without induction of apoptosis. Transcriptome analysis of late-stage responses to this UPR stimulus reveals a link between UPR activity and estrogen signaling.
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Affiliation(s)
- Kanak Raina
- 1] Department of Chemistry, Yale University New Haven, Connecticut, USA. [2]
| | - Devin J Noblin
- 1] Department of Molecular, Cellular and Developmental Biology, Yale University New Haven, Connecticut, USA. [2]
| | - Yevgeniy V Serebrenik
- Department of Molecular, Cellular and Developmental Biology, Yale University New Haven, Connecticut, USA
| | - Alison Adams
- Department of Molecular, Cellular and Developmental Biology, Yale University New Haven, Connecticut, USA
| | - Connie Zhao
- Molecular Biophysics and Biochemistry, Yale University New Haven, Connecticut, USA
| | - Craig M Crews
- 1] Department of Chemistry, Yale University New Haven, Connecticut, USA. [2] Department of Molecular, Cellular and Developmental Biology, Yale University New Haven, Connecticut, USA. [3] Department of Pharmacology, Yale University New Haven, Connecticut, USA
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377
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Hebert DN, Lamriben L, Powers ET, Kelly JW. The intrinsic and extrinsic effects of N-linked glycans on glycoproteostasis. Nat Chem Biol 2014; 10:902-10. [PMID: 25325701 PMCID: PMC4232232 DOI: 10.1038/nchembio.1651] [Citation(s) in RCA: 130] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2014] [Accepted: 08/28/2014] [Indexed: 01/29/2023]
Abstract
Proteins that traffic through the eukaryotic secretory pathway are commonly modified with N-linked carbohydrates. These bulky amphipathic modifications at asparagines intrinsically enhance solubility and folding energetics through carbohydrate-protein interactions. N-linked glycans can also extrinsically enhance glycoprotein folding by using the glycoprotein homeostasis or 'glycoproteostasis' network, which comprises numerous glycan binding and/or modification enzymes or proteins that synthesize, transfer, sculpt and use N-linked glycans to direct folding and trafficking versus degradation and trafficking of nascent N-glycoproteins through the cellular secretory pathway. If protein maturation is perturbed by misfolding, aggregation or both, stress pathways are often activated that result in transcriptional remodeling of the secretory pathway in an attempt to alleviate the insult (or insults). The inability to achieve glycoproteostasis is linked to several pathologies, including amyloidoses, cystic fibrosis and lysosomal storage diseases. Recent progress on genetic and pharmacologic adaptation of the glycoproteostasis network provides hope that drugs of this mechanistic class can be developed for these maladies in the near future.
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Affiliation(s)
- Daniel N. Hebert
- Department of Biochemistry and Molecular Biology, Program in Molecular and Cellular Biology, University of Massachusetts, Amherst, MA 01003
| | - Lydia Lamriben
- Department of Biochemistry and Molecular Biology, Program in Molecular and Cellular Biology, University of Massachusetts, Amherst, MA 01003
| | - Evan T. Powers
- Departments of Chemistry and Molecular and Experimental Medicine and the Skaggs Institute for Chemical Biology, The Scripps Research Institute, La Jolla, CA 92037
| | - Jeffery W. Kelly
- Departments of Chemistry and Molecular and Experimental Medicine and the Skaggs Institute for Chemical Biology, The Scripps Research Institute, La Jolla, CA 92037
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378
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Genereux JC, Qu S, Zhou M, Ryno LM, Wang S, Shoulders MD, Kaufman RJ, Lasmézas CI, Kelly JW, Wiseman RL. Unfolded protein response-induced ERdj3 secretion links ER stress to extracellular proteostasis. EMBO J 2014; 34:4-19. [PMID: 25361606 DOI: 10.15252/embj.201488896] [Citation(s) in RCA: 93] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
The Unfolded Protein Response (UPR) indirectly regulates extracellular proteostasis through transcriptional remodeling of endoplasmic reticulum (ER) proteostasis pathways. This remodeling attenuates secretion of misfolded, aggregation-prone proteins during ER stress. Through these activities, the UPR has a critical role in preventing the extracellular protein aggregation associated with numerous human diseases. Here, we demonstrate that UPR activation also directly influences extracellular proteostasis through the upregulation and secretion of the ER HSP40 ERdj3/DNAJB11. Secreted ERdj3 binds misfolded proteins in the extracellular space, substoichiometrically inhibits protein aggregation, and attenuates proteotoxicity of disease-associated toxic prion protein. Moreover, ERdj3 can co-secrete with destabilized, aggregation-prone proteins in a stable complex under conditions where ER chaperoning capacity is overwhelmed, preemptively providing extracellular chaperoning of proteotoxic misfolded proteins that evade ER quality control. This regulated co-secretion of ERdj3 with misfolded clients directly links ER and extracellular proteostasis during conditions of ER stress. ERdj3 is, to our knowledge, the first metazoan chaperone whose secretion into the extracellular space is regulated by the UPR, revealing a new mechanism by which UPR activation regulates extracellular proteostasis.
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Affiliation(s)
- Joseph C Genereux
- Department of Molecular & Experimental Medicine, The Scripps Research Institute, La Jolla, CA, USA Department of Chemistry, The Scripps Research Institute, La Jolla, CA, USA
| | - Song Qu
- Department of Molecular & Experimental Medicine, The Scripps Research Institute, La Jolla, CA, USA Department of Chemistry, The Scripps Research Institute, La Jolla, CA, USA Department of Chemical Physiology, The Scripps Research Institute, La Jolla, CA, USA
| | - Minghai Zhou
- Department of Infectious Diseases, The Scripps Research Institute, Jupiter, FL, USA
| | - Lisa M Ryno
- Department of Molecular & Experimental Medicine, The Scripps Research Institute, La Jolla, CA, USA Department of Chemistry, The Scripps Research Institute, La Jolla, CA, USA
| | - Shiyu Wang
- Degenerative Disease Research Program, Sanford Burnham Medical Research Institute, La Jolla, CA, USA
| | | | - Randal J Kaufman
- Degenerative Disease Research Program, Sanford Burnham Medical Research Institute, La Jolla, CA, USA
| | - Corinne I Lasmézas
- Department of Infectious Diseases, The Scripps Research Institute, Jupiter, FL, USA
| | - Jeffery W Kelly
- Department of Molecular & Experimental Medicine, The Scripps Research Institute, La Jolla, CA, USA Department of Chemistry, The Scripps Research Institute, La Jolla, CA, USA The Skaggs Institute for Chemical Biology, The Scripps Research Institute, La Jolla, CA, USA
| | - R Luke Wiseman
- Department of Molecular & Experimental Medicine, The Scripps Research Institute, La Jolla, CA, USA Department of Chemical Physiology, The Scripps Research Institute, La Jolla, CA, USA
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379
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Chambers JE, Marciniak SJ. Cellular mechanisms of endoplasmic reticulum stress signaling in health and disease. 2. Protein misfolding and ER stress. Am J Physiol Cell Physiol 2014; 307:C657-70. [PMID: 24944205 DOI: 10.1152/ajpcell.00183.2014] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The endoplasmic reticulum (ER) is a major site of protein synthesis, most strikingly in the specialized secretory cells of metazoans, which can produce their own weight in proteins daily. Cells possess a diverse machinery to ensure correct folding, assembly, and secretion of proteins from the ER. When this machinery is overwhelmed, the cell is said to experience ER stress, a result of the accumulation of unfolded or misfolded proteins in the lumen of the organelle. Here we discuss the causes of ER stress and the mechanisms by which cells elicit a response, with an emphasis on recent discoveries.
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Affiliation(s)
- Joseph E Chambers
- Department of Medicine, University of Cambridge, Cambridge Institute for Medical Research, Cambridge, United Kingdom
| | - Stefan J Marciniak
- Department of Medicine, University of Cambridge, Cambridge Institute for Medical Research, Cambridge, United Kingdom
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380
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Chiang WC, Kroeger H, Sakami S, Messah C, Yasumura D, Matthes MT, Coppinger JA, Palczewski K, LaVail MM, Lin JH. Robust Endoplasmic Reticulum-Associated Degradation of Rhodopsin Precedes Retinal Degeneration. Mol Neurobiol 2014; 52:679-95. [PMID: 25270370 DOI: 10.1007/s12035-014-8881-8] [Citation(s) in RCA: 104] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2014] [Accepted: 08/25/2014] [Indexed: 12/18/2022]
Abstract
Rhodopsin is a G protein-coupled receptor essential for vision and rod photoreceptor viability. Disease-associated rhodopsin mutations, such as P23H rhodopsin, cause rhodopsin protein misfolding and trigger endoplasmic reticulum (ER) stress, activating the unfolded protein response (UPR). The pathophysiologic effects of ER stress and UPR activation on photoreceptors are unclear. Here, by examining P23H rhodopsin knock-in mice, we found that the UPR inositol-requiring enzyme 1 (IRE1) signaling pathway is strongly activated in misfolded rhodopsin-expressing photoreceptors. IRE1 significantly upregulated ER-associated protein degradation (ERAD), triggering pronounced P23H rhodopsin degradation. Rhodopsin protein loss occurred as soon as photoreceptors developed, preceding photoreceptor cell death. By contrast, IRE1 activation did not affect JNK signaling or rhodopsin mRNA levels. Interestingly, pro-apoptotic signaling from the PERK UPR pathway was also not induced. Our findings reveal that an early and significant pathophysiologic effect of ER stress in photoreceptors is the highly efficient elimination of misfolded rhodopsin protein. We propose that early disruption of rhodopsin protein homeostasis in photoreceptors could contribute to retinal degeneration.
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Affiliation(s)
- Wei-Chieh Chiang
- Department of Pathology, University of California, San Diego, 9500 Gilman Dr., La Jolla, San Diego, CA, 92093-0612, USA
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381
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Vandewynckel YP, Laukens D, Bogaerts E, Paridaens A, Van den Bussche A, Verhelst X, Van Steenkiste C, Descamps B, Vanhove C, Libbrecht L, De Rycke R, Lambrecht BN, Geerts A, Janssens S, Van Vlierberghe H. Modulation of the unfolded protein response impedes tumor cell adaptation to proteotoxic stress: a PERK for hepatocellular carcinoma therapy. Hepatol Int 2014; 9:93-104. [PMID: 25598862 PMCID: PMC4289530 DOI: 10.1007/s12072-014-9582-0] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/14/2014] [Accepted: 09/09/2014] [Indexed: 12/22/2022]
Abstract
Background Functional disturbances of the endoplasmic reticulum (ER) lead to activation of the unfolded protein response (UPR), which is involved in the consecutive steps of carcinogenesis. In human hepatocellular carcinoma (HCC), the UPR is shown to be activated; however, little is known about the UPR kinetics and effects of UPR modulation in HCC. Methods We sequentially monitored the UPR over time in an orthotopic mouse model for HCC and explored the effects of UPR modulation on cell viability and proliferation in vitro and in the mouse model. Results The expression of ER-resident chaperones peaked during tumor initiation and increased further during tumor progression, predominantly within the nodules. A peak in Ire1 signaling was observed during tumor initiation. The Perk pathway was activated during tumor progression, and the proapoptotic target Chop was upregulated from week 5 and continued to rise, especially in the tumors. The Atf6 pathway was modestly activated only after tumor initiation. Consistent with the UPR activation, electron microscopy demonstrated ER expansion and reorganization in HCC cells in vivo. Strikingly, under ER stress or hypoxia, the Perk inhibitor and not the Ire1 inhibitor reduced cell viability and proliferation via escalating proteotoxic stress in vitro. Notably, the Perk inhibitor significantly decreased tumor burden in the mouse model. Conclusion We provide the first evaluation of the UPR dynamics in a long-term cancer model and identified a small molecule inhibitor of Perk as a promising strategy for HCC therapy. Electronic supplementary material The online version of this article (doi:10.1007/s12072-014-9582-0) contains supplementary material, which is available to authorized users.
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MESH Headings
- Activating Transcription Factor 6/genetics
- Adaptation, Physiological/drug effects
- Animals
- Carcinoma, Hepatocellular/chemistry
- Carcinoma, Hepatocellular/drug therapy
- Carcinoma, Hepatocellular/metabolism
- Carcinoma, Hepatocellular/ultrastructure
- Cell Proliferation/drug effects
- Cell Survival/drug effects
- Cell Transformation, Neoplastic/metabolism
- Endoplasmic Reticulum
- Endoplasmic Reticulum Chaperone BiP
- HSP40 Heat-Shock Proteins/genetics
- Heat-Shock Proteins/genetics
- Hep G2 Cells
- Humans
- Liver Neoplasms, Experimental/chemistry
- Liver Neoplasms, Experimental/drug therapy
- Liver Neoplasms, Experimental/metabolism
- Liver Neoplasms, Experimental/ultrastructure
- Male
- Membrane Glycoproteins/genetics
- Membrane Proteins/antagonists & inhibitors
- Membrane Proteins/genetics
- Mice
- Oxidative Stress
- Phosphorylation/drug effects
- Protein Kinase Inhibitors/pharmacology
- Protein Kinase Inhibitors/therapeutic use
- Protein Serine-Threonine Kinases/antagonists & inhibitors
- Protein Serine-Threonine Kinases/genetics
- RNA, Messenger/analysis
- Signal Transduction
- Transcription Factor CHOP/analysis
- Transcription Factor CHOP/genetics
- Tunicamycin/pharmacology
- Unfolded Protein Response/drug effects
- eIF-2 Kinase/antagonists & inhibitors
- eIF-2 Kinase/metabolism
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Affiliation(s)
- Yves-Paul Vandewynckel
- />Department of Hepatology and Gastroenterology, Ghent University, De Pintelaan 185, 1K12 IE, 9000 Ghent, Belgium
| | - Debby Laukens
- />Department of Hepatology and Gastroenterology, Ghent University, De Pintelaan 185, 1K12 IE, 9000 Ghent, Belgium
| | - Eliene Bogaerts
- />Department of Hepatology and Gastroenterology, Ghent University, De Pintelaan 185, 1K12 IE, 9000 Ghent, Belgium
| | - Annelies Paridaens
- />Department of Hepatology and Gastroenterology, Ghent University, De Pintelaan 185, 1K12 IE, 9000 Ghent, Belgium
| | - Anja Van den Bussche
- />Department of Hepatology and Gastroenterology, Ghent University, De Pintelaan 185, 1K12 IE, 9000 Ghent, Belgium
| | - Xavier Verhelst
- />Department of Hepatology and Gastroenterology, Ghent University, De Pintelaan 185, 1K12 IE, 9000 Ghent, Belgium
| | - Christophe Van Steenkiste
- />Department of Hepatology and Gastroenterology, Ghent University, De Pintelaan 185, 1K12 IE, 9000 Ghent, Belgium
| | - Benedicte Descamps
- />Infinity Imaging Lab, Ghent University, De Pintelaan 185, 9000 Ghent, Belgium
| | - Chris Vanhove
- />Infinity Imaging Lab, Ghent University, De Pintelaan 185, 9000 Ghent, Belgium
- />GROUP-ID Consortium, Ghent University Hospital, Ghent University, De Pintelaan 185, 9000 Ghent, Belgium
| | - Louis Libbrecht
- />Department of Pathology, Ghent University, De Pintelaan 185, 9000 Ghent, Belgium
| | - Riet De Rycke
- />GROUP-ID Consortium, Ghent University Hospital, Ghent University, De Pintelaan 185, 9000 Ghent, Belgium
- />Unit Immunoregulation and Mucosal Immunology, VIB Inflammation Research Center, Technologiepark 927, 9052 Ghent, Belgium
| | - Bart N. Lambrecht
- />GROUP-ID Consortium, Ghent University Hospital, Ghent University, De Pintelaan 185, 9000 Ghent, Belgium
- />Unit Immunoregulation and Mucosal Immunology, VIB Inflammation Research Center, Technologiepark 927, 9052 Ghent, Belgium
- />Department of Respiratory Medicine, Ghent University Hospital, Ghent University, De Pintelaan 185, 9000 Ghent, Belgium
| | - Anja Geerts
- />Department of Hepatology and Gastroenterology, Ghent University, De Pintelaan 185, 1K12 IE, 9000 Ghent, Belgium
| | - Sophie Janssens
- />GROUP-ID Consortium, Ghent University Hospital, Ghent University, De Pintelaan 185, 9000 Ghent, Belgium
- />Unit Immunoregulation and Mucosal Immunology, VIB Inflammation Research Center, Technologiepark 927, 9052 Ghent, Belgium
- />Department of Respiratory Medicine, Ghent University Hospital, Ghent University, De Pintelaan 185, 9000 Ghent, Belgium
| | - Hans Van Vlierberghe
- />Department of Hepatology and Gastroenterology, Ghent University, De Pintelaan 185, 1K12 IE, 9000 Ghent, Belgium
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382
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Dufey E, Sepúlveda D, Rojas-Rivera D, Hetz C. Cellular Mechanisms of Endoplasmic Reticulum Stress Signaling in Health and Disease. 1. An overview. Am J Physiol Cell Physiol 2014; 307:C582-94. [DOI: 10.1152/ajpcell.00258.2014] [Citation(s) in RCA: 137] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Increased demand on the protein folding capacity of the endoplasmic reticulum (ER) engages an adaptive reaction known as the unfolded protein response (UPR). The UPR regulates protein translation and the expression of numerous target genes that contribute to restore ER homeostasis or induce apoptosis of irreversibly damaged cells. UPR signaling is highly regulated and dynamic and integrates information about the type, intensity, and duration of the stress stimuli, thereby determining cell fate. Recent advances highlight novel physiological outcomes of the UPR beyond specialized secretory cells, particularly in innate immunity, metabolism, and cell differentiation. Here we discuss studies on the fine-tuning of the UPR and its physiological role in diverse organs and diseases.
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Affiliation(s)
- Estefanie Dufey
- Biomedical Neuroscience Institute, Faculty of Medicine, University of Chile, Santiago, Chile
- Program of Cellular and Molecular Biology, Institute of Biomedical Sciences, Center for Molecular Studies of the Cell, University of Chile, Santiago, Chile
| | - Denisse Sepúlveda
- Biomedical Neuroscience Institute, Faculty of Medicine, University of Chile, Santiago, Chile
- Program of Cellular and Molecular Biology, Institute of Biomedical Sciences, Center for Molecular Studies of the Cell, University of Chile, Santiago, Chile
| | - Diego Rojas-Rivera
- Biomedical Neuroscience Institute, Faculty of Medicine, University of Chile, Santiago, Chile
- Program of Cellular and Molecular Biology, Institute of Biomedical Sciences, Center for Molecular Studies of the Cell, University of Chile, Santiago, Chile
| | - Claudio Hetz
- Biomedical Neuroscience Institute, Faculty of Medicine, University of Chile, Santiago, Chile
- Program of Cellular and Molecular Biology, Institute of Biomedical Sciences, Center for Molecular Studies of the Cell, University of Chile, Santiago, Chile
- Department of Immunology and Infectious Diseases, Harvard School of Public Health, Boston, Massachusetts; and
- Neurounion Biomedical Foundation, CENPAR, Santiago, Chile
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383
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Zhang X, Liu Y, Genereux JC, Nolan C, Singh M, Kelly JW. Heat-shock response transcriptional program enables high-yield and high-quality recombinant protein production in Escherichia coli. ACS Chem Biol 2014; 9:1945-9. [PMID: 25051296 PMCID: PMC4168666 DOI: 10.1021/cb5004477] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
![]()
The biosynthesis of soluble, properly
folded recombinant proteins
in large quantities from Escherichia coli is desirable
for academic research and industrial protein production. The basal E. coli protein homeostasis (proteostasis) network capacity
is often insufficient to efficiently fold overexpressed proteins.
Herein we demonstrate that a transcriptionally reprogrammed E. coli proteostasis network is generally superior for producing
soluble, folded, and functional recombinant proteins. Reprogramming
is accomplished by overexpressing a negative feedback deficient heat-shock
response
transcription factor before and during overexpression of the protein-of-interest.
The advantage of transcriptional reprogramming versus simply overexpressing
select proteostasis network components (e.g., chaperones and co-chaperones,
which has been explored previously) is that a large number of proteostasis
network components are upregulated at their evolved stoichiometry,
thus maintaining the system capabilities of the proteostasis network
that are currently incompletely understood. Transcriptional proteostasis
network reprogramming mediated by stress-responsive signaling in the
absence of stress should also be useful for protein production in
other cells.
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Affiliation(s)
- Xin Zhang
- Department of Chemistry, ‡Department of Molecular and Experimental
Medicine, and §Department of
Chemical Physiology, ∥The Skaggs Institute for Chemical Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, California 92037, United States
| | - Yu Liu
- Department of Chemistry, ‡Department of Molecular and Experimental
Medicine, and §Department of
Chemical Physiology, ∥The Skaggs Institute for Chemical Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, California 92037, United States
| | - Joseph C. Genereux
- Department of Chemistry, ‡Department of Molecular and Experimental
Medicine, and §Department of
Chemical Physiology, ∥The Skaggs Institute for Chemical Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, California 92037, United States
| | - Chandler Nolan
- Department of Chemistry, ‡Department of Molecular and Experimental
Medicine, and §Department of
Chemical Physiology, ∥The Skaggs Institute for Chemical Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, California 92037, United States
| | - Meha Singh
- Department of Chemistry, ‡Department of Molecular and Experimental
Medicine, and §Department of
Chemical Physiology, ∥The Skaggs Institute for Chemical Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, California 92037, United States
| | - Jeffery W. Kelly
- Department of Chemistry, ‡Department of Molecular and Experimental
Medicine, and §Department of
Chemical Physiology, ∥The Skaggs Institute for Chemical Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, California 92037, United States
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384
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Unfolded protein response activation reduces secretion and extracellular aggregation of amyloidogenic immunoglobulin light chain. Proc Natl Acad Sci U S A 2014; 111:13046-51. [PMID: 25157167 DOI: 10.1073/pnas.1406050111] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Light-chain amyloidosis (AL) is a degenerative disease characterized by the extracellular aggregation of a destabilized amyloidogenic Ig light chain (LC) secreted from a clonally expanded plasma cell. Current treatments for AL revolve around ablating the cancer plasma cell population using chemotherapy regimens. Unfortunately, this approach is limited to the ∼ 70% of patients who do not exhibit significant organ proteotoxicity and can tolerate chemotherapy. Thus, identifying new therapeutic strategies to alleviate LC organ proteotoxicity should allow AL patients with significant cardiac and/or renal involvement to subsequently tolerate established chemotherapy treatments. Using a small-molecule screening approach, the unfolded protein response (UPR) was identified as a cellular signaling pathway whose activation selectively attenuates secretion of amyloidogenic LC, while not affecting secretion of a nonamyloidogenic LC. Activation of the UPR-associated transcription factors XBP1s and/or ATF6 in the absence of stress recapitulates the selective decrease in amyloidogenic LC secretion by remodeling the endoplasmic reticulum proteostasis network. Stress-independent activation of XBP1s, or especially ATF6, also attenuates extracellular aggregation of amyloidogenic LC into soluble aggregates. Collectively, our results show that stress-independent activation of these adaptive UPR transcription factors offers a therapeutic strategy to reduce proteotoxicity associated with LC aggregation.
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385
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Wong KL, Wu YR, Cheng KS, Chan P, Cheung CW, Lu DY, Su TH, Liu ZM, Leung YM. Palmitic acid-induced lipotoxicity and protection by (+)-catechin in rat cortical astrocytes. Pharmacol Rep 2014; 66:1106-13. [PMID: 25443742 DOI: 10.1016/j.pharep.2014.07.009] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2014] [Revised: 07/22/2014] [Accepted: 07/24/2014] [Indexed: 12/20/2022]
Abstract
BACKGROUND Astrocytes do not only maintain homeostasis of the extracellular milieu of the neurons, but also play an active role in modulating synaptic transmission. Palmitic acid (PA) is a saturated fatty acid which, when being excessive, is a significant risk factor for lipotoxicity. Activation of astrocytes by PA has been shown to cause neuronal inflammation and demyelination. However, direct damage by PA to astrocytes is relatively unexplored. The aim of this study was to identify the mechanism(s) of PA-induced cytotoxicity in rat cortical astrocytes and possible protection by (+)-catechin. METHODS Cytotoxicity and endoplasmic reticulum (ER) markers were assessed by MTT assay and Western blotting, respectively. Cytosolic Ca(2+) and mitochondrial membrane potential (MMP) were measured microfluorimetrically using fura-2 and rhodamine 123, respectively. Intracellular reactive oxygen species (ROS) production was assayed by the indicator 2'-7'-dichlorodihydrofluorescein diacetate. RESULTS Exposure of astrocytes to 100μM PA for 24h resulted in apoptotic cell death. Whilst PA-induced cell death appeared to be unrelated to ER stress and perturbation in cytosolic Ca(2+) signaling, it was likely a result of ROS production and subsequent MMP collapse, since ascorbic acid (anti-oxidant, 100μM) prevented PA-induced MMP collapse and cell death. Co-treatment of astrocytes with (+)-catechin (300μM), an anti-oxidant found abundantly in green tea, significantly prevented PA-induced ROS production, MMP collapse and cell death. CONCLUSION Our results suggest that PA-induced cytotoxicity in astrocytes may involve ROS generation and MMP collapse, which can be prevented by (+)-catechin.
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Affiliation(s)
- Kar-Lok Wong
- Department of Anesthesiology, China Medical University and Hospital, Taichung, Taiwan; Department of Anesthesiology, LKS Faculty of Medicine, University of Hong Kong, Hong Kong; Department of Anesthesiology, Shandong University Nanshan Branch of Qilu Hospital, China
| | - Yu-Ru Wu
- Graduate Institute of Neural and Cognitive Sciences, China Medical University, Taichung, Taiwan
| | - Ka-Shun Cheng
- Department of Anesthesiology, China Medical University and Hospital, Taichung, Taiwan
| | - Paul Chan
- Division of Cardiology, Department of Medicine, Taipei Medical University Wan Fan Hospital, Taipei, Taiwan
| | - Chi-Wai Cheung
- Department of Anesthesiology, LKS Faculty of Medicine, University of Hong Kong, Hong Kong
| | - Dah-Yuu Lu
- Graduate Institute of Neural and Cognitive Sciences, China Medical University, Taichung, Taiwan
| | - Tzu-Hui Su
- Department of Anesthesiology, China Medical University and Hospital, Taichung, Taiwan
| | - Zhong-Min Liu
- Department of Cardiovascular Surgery, Shanghai East Hospital, Tongji University, Shanghai, China.
| | - Yuk-Man Leung
- Graduate Institute of Neural and Cognitive Sciences, China Medical University, Taichung, Taiwan.
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386
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Ryno LM, Genereux J, Naito T, Morimoto RI, Powers ET, Shoulders MD, Wiseman RL. Characterizing the altered cellular proteome induced by the stress-independent activation of heat shock factor 1. ACS Chem Biol 2014; 9:1273-83. [PMID: 24689980 PMCID: PMC4076015 DOI: 10.1021/cb500062n] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2014] [Accepted: 04/01/2014] [Indexed: 01/18/2023]
Abstract
The heat shock response is an evolutionarily conserved, stress-responsive signaling pathway that adapts cellular proteostasis in response to pathologic insult. In metazoans, the heat shock response primarily functions through the posttranslational activation of heat shock factor 1 (HSF1), a stress-responsive transcription factor that induces the expression of cytosolic proteostasis factors including chaperones, cochaperones, and folding enzymes. HSF1 is a potentially attractive therapeutic target to ameliorate pathologic imbalances in cellular proteostasis associated with human disease, although the underlying impact of stress-independent HSF1 activation on cellular proteome composition remains to be defined. Here, we employ a highly controllable, ligand-regulated HSF1 that activates HSF1 to levels compatible with those that could be achieved using selective small molecule HSF1 activators. Using a combination of RNAseq and quantitative proteomics, we define the impact of stress-independent HSF1 activation on the composition of the cellular proteome. We show that stress-independent HSF1 activation selectively remodels cytosolic proteostasis pathways without globally influencing the composition of the cellular proteome. Furthermore, we show that stress-independent HSF1 activation decreases intracellular aggregation of a model polyglutamine-containing protein and reduces the cellular toxicity of environmental toxins like arsenite that disrupt cytosolic proteostasis. Collectively, our results reveal a proteome-level view of stress-independent HSF1 activation, providing a framework to establish therapeutic approaches to correct pathologic imbalances in cellular proteostasis through the selective targeting of HSF1.
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Affiliation(s)
- Lisa M. Ryno
- Department
of Molecular & Experimental Medicine, Department of Chemical Physiology, The Scripps Research Institute, La Jolla, California 92037, United States
| | - Joseph
C. Genereux
- Department
of Molecular & Experimental Medicine, Department of Chemical Physiology, The Scripps Research Institute, La Jolla, California 92037, United States
| | - Tadasuke Naito
- Department
of Molecular Biosciences, Rice Institute for Biomedical Research, Northwestern University, Evanston, Illinois 60208, United States
| | - Richard I. Morimoto
- Department
of Molecular Biosciences, Rice Institute for Biomedical Research, Northwestern University, Evanston, Illinois 60208, United States
| | - Evan T. Powers
- Department
of Chemistry, The Scripps Research Institute, La Jolla, California 92037, United States
| | - Matthew D. Shoulders
- Department
of Molecular & Experimental Medicine, Department of Chemical Physiology, The Scripps Research Institute, La Jolla, California 92037, United States
- Department
of Chemistry, Massachusetts Institute of
Technology, Cambridge, Massachusetts 02139, United States
| | - R. Luke Wiseman
- Department
of Molecular & Experimental Medicine, Department of Chemical Physiology, The Scripps Research Institute, La Jolla, California 92037, United States
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387
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Le Pape S, Dimitrova E, Hannaert P, Konovalov A, Volmer R, Ron D, Thuillier R, Hauet T. Polynomial algebra reveals diverging roles of the unfolded protein response in endothelial cells during ischemia-reperfusion injury. FEBS Lett 2014; 588:3062-7. [PMID: 24945730 DOI: 10.1016/j.febslet.2014.05.065] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2014] [Revised: 05/23/2014] [Accepted: 05/30/2014] [Indexed: 11/16/2022]
Abstract
The unfolded protein response (UPR)--the endoplasmic reticulum stress response--is found in various pathologies including ischemia-reperfusion injury (IRI). However, its role during IRI is still unclear. Here, by combining two different bioinformatical methods--a method based on ordinary differential equations (Time Series Network Inference) and an algebraic method (probabilistic polynomial dynamical systems)--we identified the IRE1α-XBP1 and the ATF6 pathways as the main UPR effectors involved in cell's adaptation to IRI. We validated these findings experimentally by assessing the impact of their knock-out and knock-down on cell survival during IRI.
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Affiliation(s)
- Sylvain Le Pape
- IRTOMIT, INSERM UMR 1082, Université de Médecine et de Pharmacie de Poitiers, Rue de la Milétrie, 86021 Poitiers, France.
| | - Elena Dimitrova
- Mathematical Sciences, Clemson University, Martin O-303, Clemson, SC 29634-0975, United States
| | - Patrick Hannaert
- IRTOMIT, INSERM UMR 1082, Université de Médecine et de Pharmacie de Poitiers, Rue de la Milétrie, 86021 Poitiers, France
| | - Alexander Konovalov
- Centre for Interdisciplinary Research in Computational Algebra, School of Computer Science, University of St Andrews, St Andrews, Fife KY16 9SX, Scotland, United Kingdom
| | - Romain Volmer
- University of Cambridge Metabolic Research Laboratories and National Institute for Health Research, Cambridge Biomedical Research Centre, CB2 0QQ Cambridge, United Kingdom
| | - David Ron
- University of Cambridge Metabolic Research Laboratories and National Institute for Health Research, Cambridge Biomedical Research Centre, CB2 0QQ Cambridge, United Kingdom
| | - Raphaël Thuillier
- IRTOMIT, INSERM UMR 1082, Université de Médecine et de Pharmacie de Poitiers, Rue de la Milétrie, 86021 Poitiers, France
| | - Thierry Hauet
- IRTOMIT, INSERM UMR 1082, Université de Médecine et de Pharmacie de Poitiers, Rue de la Milétrie, 86021 Poitiers, France
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388
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Pluquet O, Dejeans N, Chevet E. Watching the clock: endoplasmic reticulum-mediated control of circadian rhythms in cancer. Ann Med 2014; 46:233-43. [PMID: 24491143 DOI: 10.3109/07853890.2013.874664] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
In the past 20 years both the circadian clock and endoplasmic reticulum (ER) stress signaling have emerged as major players in oncogenesis and cancer development. Although several lines of evidence have established functional links between these two molecular pathways, their interconnection and the subsequent functional implications in cancer development remain to be fully characterized. Herein, we provide an extensive review of the literature depicting the molecular connectivity linking ER stress signaling and the circadian clock and elaborate on the potential use of these functional interactions in cancer therapeutics.
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Affiliation(s)
- Olivier Pluquet
- Institut de Biologie de Lille, CNRS UMR8161/Universités Lille 1 et Lille 2/Institut Pasteur de Lille , 1, rue du Pr. Calmette, BP 447, 59021 Lille , France
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389
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Coelho DS, Domingos PM. Physiological roles of regulated Ire1 dependent decay. Front Genet 2014; 5:76. [PMID: 24795742 PMCID: PMC3997004 DOI: 10.3389/fgene.2014.00076] [Citation(s) in RCA: 84] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2014] [Accepted: 03/24/2014] [Indexed: 12/17/2022] Open
Abstract
Inositol-requiring enzyme 1 (Ire1) is an important transducer of the unfolded protein response (UPR) that is activated by the accumulation of misfolded proteins in the endoplamic reticulum (ER stress). Activated Ire1 mediates the splicing of an intron from the mRNA of Xbp1, causing a frame-shift during translation and introducing a new carboxyl domain in the Xbp1 protein, which only then becomes a fully functional transcription factor. Studies using cell culture systems demonstrated that Ire1 also promotes the degradation of mRNAs encoding mostly ER-targeted proteins, to reduce the load of incoming ER “client” proteins during ER stress. This process was called RIDD (regulated Ire1-dependent decay), but its physiological significance remained poorly characterized beyond cell culture systems. Here we review several recent studies that have highlighted the physiological roles of RIDD in specific biological paradigms, such as photoreceptor differentiation in Drosophila or mammalian liver and endocrine pancreas function. These studies demonstrate the importance of RIDD in tissues undergoing intense secretory function and highlight the physiologic role of RIDD during UPR activation in cells and organisms.
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Affiliation(s)
- Dina S Coelho
- Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa Oeiras, Portugal
| | - Pedro M Domingos
- Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa Oeiras, Portugal
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390
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Biochemical evidence that regulation of Ero1β activity in human cells does not involve the isoform-specific cysteine 262. Biosci Rep 2014; 34:BSR20130124. [PMID: 27919037 PMCID: PMC3971451 DOI: 10.1042/bsr20130124] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2013] [Revised: 01/08/2014] [Accepted: 01/28/2014] [Indexed: 12/13/2022] Open
Abstract
In the ER (endoplasmic reticulum) of human cells, disulfide bonds are predominantly generated by the two isoforms of Ero1 (ER oxidoreductin-1): Ero1α and Ero1β. The activity of Ero1α is tightly regulated through the formation of intramolecular disulfide bonds to help ensure balanced ER redox conditions. Ero1β is less tightly regulated, but the molecular details underlying control of activity are not as well characterized as for Ero1α. Ero1β contains an additional cysteine residue (Cys262), which has been suggested to engage in an isoform-specific regulatory disulfide bond with Cys100. However, we show that the two regulatory disulfide bonds in Ero1α are likely conserved in Ero1β (Cys90–Cys130 and Cys95–Cys100). Molecular modelling of the Ero1β structure predicted that the side chain of Cys262 is completely buried. Indeed, we found this cysteine to be reduced and partially protected from alkylation in the ER of living cells. Furthermore, mutation of Cys100–but not of Cys262–rendered Ero1β hyperactive in cells, as did mutation of Cys130. Ero1β hyperactivity induced the UPR (unfolded protein response) and resulted in oxidative perturbation of the ER redox state. We propose that features other than a distinct pattern of regulatory disulfide bonds determine the loose redox regulation of Ero1β relative to Ero1α. Our findings indicate that the regulatory disulfide bonds are conserved in the human oxidases Ero1α and Ero1β. We therefore propose that features other than a distinct pattern of disulfide bonds determine the previously established difference in regulation of Ero1α and Ero1β activity.
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391
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Kim T, Do MHT, Lawson MA. Translational control of gene expression in the gonadotrope. Mol Cell Endocrinol 2014; 385:78-87. [PMID: 24035865 PMCID: PMC4009948 DOI: 10.1016/j.mce.2013.09.007] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/04/2013] [Revised: 08/30/2013] [Accepted: 09/03/2013] [Indexed: 12/15/2022]
Abstract
The study of gene expression in gonadotropes has largely focused on the variety of mechanisms regulating transcription of the gonadotropin genes and ancillary factors that contribute to the overall phenotype and function of these cells in reproduction. However, there are aspects of the response to GNRH signaling that are not readily explained by changes at the level of transcription. As our understanding of regulation at the level of mRNA translation has increased, it has become evident that GNRH receptor signaling engages multiple aspects of translational regulation. This includes activation of cap-dependent translation initiation, translational pausing caused by the unfolded protein response and RNA binding protein interaction. Gonadotropin mRNAs and the mRNAs of other factors that control the transcriptional and signaling responses to GNRH have been identified as targets of regulation at the level of translation. In this review we examine the impact of translational control of the expression of gonadotropin genes and other genes relevant to GNRH-mediated control of gonadotrope function.
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Affiliation(s)
- Taeshin Kim
- Department of Reproductive Medicine, University of California, San Diego, La Jolla, CA 92093, United States
| | - Minh-Ha T Do
- Department of Reproductive Medicine, University of California, San Diego, La Jolla, CA 92093, United States
| | - Mark A Lawson
- Department of Reproductive Medicine, University of California, San Diego, La Jolla, CA 92093, United States.
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392
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Kim EJ, Lee YJ, Kang S, Lim YB. Ionizing radiation activates PERK/eIF2α/ATF4 signaling via ER stress-independent pathway in human vascular endothelial cells. Int J Radiat Biol 2014; 90:306-12. [PMID: 24456547 DOI: 10.3109/09553002.2014.886793] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
PURPOSE Perturbations in protein folding induce endoplasmic reticulum (ER) stress, which elicits coordinated response, namely the unfolded protein response (UPR), to cope with the accumulation of misfolded proteins in ER. In this study, we characterized mechanisms underlying ionizing radiation (IR)-induced UPR signaling pathways. MATERIALS AND METHODS We analyzed alterations in UPR signaling pathways in human umbilical vein endothelial cells (HUVEC) and human coronary artery endothelial cells (HCAEC) irradiated with 15 Gy IR. RESULTS IR selectively activated the eIF2α/ATF4 branch of the UPR signaling pathway, with no alterations in the IRE1 and ATF6 branches in HUVEC and HCAEC. Phosphorylation of PERK was enhanced in response to IR, and the IR-induced activation of the eIF2α/ATF4 signaling pathway was completely inhibited by PERK knockdown with siRNA. Surprisingly, chemical chaperones, which inhibit the formation of misfolded proteins and sequential protein aggregates to reduce ER stress, failed to prevent the IR-induced phosphorylation of PERK and the subsequent activation of the eIF2α/ATF4 signaling pathway. CONCLUSIONS PERK mediates the IR-induced selective activation of the eIF2α/ATF4 signaling pathway, and the IR-induced activation of PERK/eIF2α/ATF4 signaling in human vascular endothelial cells is independent of alterations in protein-folding homeostasis in the ER.
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Affiliation(s)
- Eun Ju Kim
- Division of Radiation Effects, Korea Institute of Radiological and Medical Sciences , Seoul
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393
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Wu L, Chou M, Zhu S. Unfolded Protein Response and Cancer. Discoveries (Craiova) 2014; 2:e10. [PMID: 32309542 PMCID: PMC6941583 DOI: 10.15190/d.2014.2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2014] [Revised: 03/13/2014] [Accepted: 03/13/2014] [Indexed: 11/22/2022] Open
Abstract
Physiological stresses, such as hypoxia and oxidative stress, induce protein misfolding in the endoplasmic reticulum (ER). If proteasome degradation fails to remove the misfolded proteins, these proteins accumulate in the ER, triggering the unfolded protein response (UPR). UPR involves a series of responses, such as the suppression of global protein synthesis and the select expression of a set of proteins to reduce ER stress and restore the homeostasis of ER. In different stages of tumor development, hypoxia occurs and UPR is initiated. The roles of UPR in cancer development are complex, involving angiogenesis, cell survival and proliferation. The current knowledge of the molecular mechanisms involved in UPR, particularly its role in the development of cancer, is discussed.
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Affiliation(s)
- Lihua Wu
- School of Life Sciences, State Key Laboratory of Medical Genetics, Central South University, Changsha, China
| | - Mary Chou
- Advanced Orthomolecular Research Inc., Calgary, Canada
| | - Shudong Zhu
- School of Life Sciences, State Key Laboratory of Medical Genetics, Central South University, Changsha, China
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394
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Hetz C, Mollereau B. Disturbance of endoplasmic reticulum proteostasis in neurodegenerative diseases. Nat Rev Neurosci 2014; 15:233-49. [PMID: 24619348 DOI: 10.1038/nrn3689] [Citation(s) in RCA: 513] [Impact Index Per Article: 51.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The unfolded protein response (UPR) is a homeostatic mechanism by which cells regulate levels of misfolded proteins in the endoplasmic reticulum (ER). Although it is well characterized in non-neuronal cells, a proliferation of papers over the past few years has revealed a key role for the UPR in normal neuronal function and as an important driver of neurodegenerative diseases. A complex scenario is emerging in which distinct UPR signalling modules have specific and even opposite effects on neurodegeneration depending on the disease context. Here, we provide an overview of the most recent findings addressing the biological relevance of ER stress in the nervous system.
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Affiliation(s)
- Claudio Hetz
- 1] Biomedical Neuroscience Institute, Faculty of Medicine, University of Chile, Santiago, Chile. [2] Institute of Biomedical Sciences, Center for Molecular Studies of the Cell, Program of Cellular and Molecular Biology, University of Chile, Santiago, Chile. [3] Neurounion Biomedical Foundation, Santiago, Chile. [4] Department of Immunology and Infectious Diseases, Harvard School of Public Health, Boston, Massachusetts 02115, USA
| | - Bertrand Mollereau
- Laboratory of Molecular Biology of the Cell, CNRS UMR5239, Ecole Normale Supérieure de Lyon, UMS3444 Biosciences Lyon Gerland, University of Lyon, Lyon 69364, France
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395
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Eletto D, Eletto D, Dersh D, Gidalevitz T, Argon Y. Protein disulfide isomerase A6 controls the decay of IRE1α signaling via disulfide-dependent association. Mol Cell 2014; 53:562-576. [PMID: 24508390 DOI: 10.1016/j.molcel.2014.01.004] [Citation(s) in RCA: 171] [Impact Index Per Article: 17.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2013] [Revised: 11/25/2013] [Accepted: 01/03/2014] [Indexed: 11/29/2022]
Abstract
The response to endoplasmic reticulum (ER) stress relies on activation of unfolded protein response (UPR) sensors, and the outcome of the UPR depends on the duration and strength of signal. Here, we demonstrate a mechanism that attenuates the activity of the UPR sensor inositol-requiring enzyme 1α (IRE1α). A resident ER protein disulfide isomerase, PDIA6, limits the duration of IRE1α activity by direct binding to cysteine 148 in the lumenal domain of the sensor, which is oxidized when IRE1 is activated. PDIA6-deficient cells hyperrespond to ER stress with sustained autophosphorylation of IRE1α and splicing of XBP1 mRNA, resulting in exaggerated upregulation of UPR target genes and increased apoptosis. In vivo, PDIA6-deficient C. elegans exhibits constitutive UPR and fails to complete larval development, a program that normally requires the UPR. Thus, PDIA6 activity provides a mechanism that limits UPR signaling and maintains it within a physiologically appropriate range.
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Affiliation(s)
- Davide Eletto
- Department of Pathology and Laboratory Medicine, The Children's Hospital of Philadelphia and The University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Daniela Eletto
- Department of Pathology and Laboratory Medicine, The Children's Hospital of Philadelphia and The University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Devin Dersh
- Department of Pathology and Laboratory Medicine, The Children's Hospital of Philadelphia and The University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Tali Gidalevitz
- Department of Biology, Drexel University, Philadelphia, PA 19104, USA
| | - Yair Argon
- Department of Pathology and Laboratory Medicine, The Children's Hospital of Philadelphia and The University of Pennsylvania, Philadelphia, PA 19104, USA
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396
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Mass spectrometry-based quantification of the cellular response to methyl methanesulfonate treatment in human cells. DNA Repair (Amst) 2014; 15:29-38. [PMID: 24461736 DOI: 10.1016/j.dnarep.2013.12.007] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2013] [Revised: 10/21/2013] [Accepted: 12/29/2013] [Indexed: 11/23/2022]
Abstract
Faithful transmission of genetic material is essential for cell viability and organism health. The occurrence of DNA damage, due to either spontaneous events or environmental agents, threatens the integrity of the genome. The consequences of these insults, if allowed to perpetuate and accumulate over time, are mutations that can lead to the development of diseases such as cancer. Alkylation is a relevant DNA lesion produced endogenously as well as by exogenous agents including certain chemotherapeutics. We sought to better understand the cellular response to this form of DNA damage using mass spectrometry-based proteomics. For this purpose, we performed sub-cellular fractionation to monitor the effect of methyl methanesulfonate (MMS) treatment on protein localization to chromatin. The levels of over 500 proteins were increased in the chromatin-enriched nuclear lysate including histone chaperones. Levels of ubiquitin and subunits of the proteasome were also increased within this fraction, suggesting that ubiquitin-mediated degradation by the proteasome has an important role in the chromatin response to MMS treatment. Finally, the levels of some proteins were decreased within the chromatin-enriched lysate including components of the nuclear pore complex. Our spatial proteomics data demonstrate that many proteins that influence chromatin organization are regulated in response to MMS treatment, presumably to open the DNA to allow access by other DNA damage response proteins. To gain further insight into the cellular response to MMS-induced DNA damage, we also performed phosphorylation enrichment on total cell lysates to identify proteins regulated via post-translational modification. Phosphoproteomic analysis demonstrated that many nuclear phosphorylation events were decreased in response to MMS treatment. This reflected changes in protein kinase and/or phosphatase activity in response to DNA damage rather than changes in total protein abundance. Using these two mass spectrometry-based approaches, we have identified a novel set of MMS-responsive proteins that will expand our understanding of DNA damage signaling.
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397
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Osorio F, Tavernier SJ, Hoffmann E, Saeys Y, Martens L, Vetters J, Delrue I, De Rycke R, Parthoens E, Pouliot P, Iwawaki T, Janssens S, Lambrecht BN. The unfolded-protein-response sensor IRE-1α regulates the function of CD8α+ dendritic cells. Nat Immunol 2014; 15:248-57. [DOI: 10.1038/ni.2808] [Citation(s) in RCA: 180] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2013] [Accepted: 12/09/2013] [Indexed: 12/14/2022]
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398
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Rainbolt TK, Atanassova N, Genereux JC, Wiseman RL. Stress-regulated translational attenuation adapts mitochondrial protein import through Tim17A degradation. Cell Metab 2013; 18:908-19. [PMID: 24315374 PMCID: PMC3904643 DOI: 10.1016/j.cmet.2013.11.006] [Citation(s) in RCA: 141] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/31/2013] [Revised: 08/08/2013] [Accepted: 11/06/2013] [Indexed: 12/28/2022]
Abstract
Stress-regulated signaling pathways protect mitochondrial proteostasis and function from pathologic insults. Despite the importance of stress-regulated signaling pathways in mitochondrial proteome maintenance, the molecular mechanisms by which these pathways maintain mitochondrial proteostasis remain largely unknown. We identify Tim17A as a stress-regulated subunit of the translocase of the inner membrane 23 (TIM23) mitochondrial protein import complex. We show that Tim17A protein levels are decreased downstream of stress-regulated translational attenuation induced by eukaryotic initiation factor 2α (eIF2α) phosphorylation through a mechanism dependent on the mitochondrial protease YME1L. Furthermore, we demonstrate that decreasing Tim17A attenuates TIM23-dependent protein import, promotes the induction of mitochondrial unfolded protein response (UPR)-associated proteostasis genes, and confers stress resistance in C. elegans and mammalian cells. Thus, our results indicate that Tim17A degradation is a stress-responsive mechanism by which cells adapt mitochondrial protein import efficiency and promote mitochondrial proteostasis in response to the numerous pathologic insults that induce stress-regulated translation attenuation.
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Affiliation(s)
- T Kelly Rainbolt
- Department of Molecular & Experimental Medicine, Department of Chemical Physiology, The Scripps Research Institute, La Jolla, CA 92037, USA
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399
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Cornejo VH, Pihán P, Vidal RL, Hetz C. Role of the unfolded protein response in organ physiology: Lessons from mouse models. IUBMB Life 2013; 65:962-75. [DOI: 10.1002/iub.1224] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2013] [Accepted: 10/07/2013] [Indexed: 12/13/2022]
Affiliation(s)
- Víctor Hugo Cornejo
- Biomedical Neuroscience Institute; Faculty of Medicine, University of Chile; Santiago Chile
- Center for Molecular Studies of the Cell; Program of Cellular and Molecular Biology; Institute of Biomedical Sciences; University of Chile; Santiago Chile
| | - Philippe Pihán
- Biomedical Neuroscience Institute; Faculty of Medicine, University of Chile; Santiago Chile
- Center for Molecular Studies of the Cell; Program of Cellular and Molecular Biology; Institute of Biomedical Sciences; University of Chile; Santiago Chile
| | | | - Claudio Hetz
- Biomedical Neuroscience Institute; Faculty of Medicine, University of Chile; Santiago Chile
- Center for Molecular Studies of the Cell; Program of Cellular and Molecular Biology; Institute of Biomedical Sciences; University of Chile; Santiago Chile
- Neurounion Biomedical Foundation; Santiago Chile
- Department of Immunology and Infectious Diseases; Harvard School of Public Health; Boston MA USA
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400
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Hetz C, Chevet E, Harding HP. Targeting the unfolded protein response in disease. Nat Rev Drug Discov 2013; 12:703-19. [DOI: 10.1038/nrd3976] [Citation(s) in RCA: 683] [Impact Index Per Article: 62.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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