1
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Hanson FM, Ribeiro de Oliveira MI, Cross AK, Allen KE, Campbell SG. eIF2B localization and its regulation during the integrated stress response is cell-type specific. iScience 2024; 27:110851. [PMID: 39310746 PMCID: PMC11414691 DOI: 10.1016/j.isci.2024.110851] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2024] [Revised: 04/30/2024] [Accepted: 08/27/2024] [Indexed: 09/25/2024] Open
Abstract
Eukaryotic initiation factor 2B (eIF2B) controls translation initiation by recycling inactive eIF2-GDP to active eIF2-GTP. Under cellular stress, the integrated stress response (ISR) is activated inhibiting eIF2B activity resulting in the translation attenuation and reprogramming of gene expression to overcome the stress. The ISR can dictate cell fate wherein chronic activation has pathological outcomes. Vanishing white matter disease (VWMD) is a chronic ISR-related disorder with mutations in eIF2B targeting astrocyte and oligodendrocyte cells. Regulation of eIF2B localization (eIF2B bodies) has been implicated in the ISR. We present evidence that neuronal and glial cell types possess distinct patterns of eIF2B bodies which change in a manner correlating to acute and chronic ISR activation. We also demonstrate that while neural and glial cell types respond similarly to the acute induction of the ISR a chronic ISR exerts cell-type specific differences. These findings provide key insights into neural cell responses and adaptation to cellular stress.
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Affiliation(s)
- Filipe M. Hanson
- Biomolecular Sciences Research Centre, Industry and Innovation Research Institute (IRI), Sheffield Hallam University, Sheffield S1 1WB, UK
| | - Madalena I. Ribeiro de Oliveira
- Biomolecular Sciences Research Centre, Industry and Innovation Research Institute (IRI), Sheffield Hallam University, Sheffield S1 1WB, UK
| | - Alison K. Cross
- Biomolecular Sciences Research Centre, Industry and Innovation Research Institute (IRI), Sheffield Hallam University, Sheffield S1 1WB, UK
| | - K. Elizabeth Allen
- Biomolecular Sciences Research Centre, Industry and Innovation Research Institute (IRI), Sheffield Hallam University, Sheffield S1 1WB, UK
| | - Susan G. Campbell
- Biomolecular Sciences Research Centre, Industry and Innovation Research Institute (IRI), Sheffield Hallam University, Sheffield S1 1WB, UK
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2
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Zhang C, Xu H, Tang Q, Duan Y, Xia H, Huang H, Ye D, Bi F. CaMKII suppresses proteotoxicity by phosphorylating BAG3 in response to proteasomal dysfunction. EMBO Rep 2024:10.1038/s44319-024-00248-w. [PMID: 39261742 DOI: 10.1038/s44319-024-00248-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2024] [Revised: 08/09/2024] [Accepted: 08/23/2024] [Indexed: 09/13/2024] Open
Abstract
Protein quality control serves as the primary defense mechanism for cells against proteotoxicity induced by proteasome dysfunction. While cells can limit the build-up of ubiquitinated misfolded proteins during proteasome inhibition, the precise mechanism is unclear. Here, we find that protein kinase Ca2+/Calmodulin (CaM)-dependent protein kinase II (CaMKII) maintains proteostasis during proteasome inhibition. We show that proteasome inhibition activates CaMKII, which phosphorylates B-cell lymphoma 2 (Bcl-2)-associated athanogene 3 (BAG3) at residues S173, S377, and S386. Phosphorylated BAG3 activates the heme-regulated inhibitor (HRI)- eukaryotic initiation factor-2α (eIF2α) signaling pathway, suppressing protein synthesis and the production of aggregated ubiquitinated misfolded proteins, ultimately mitigating the proteotoxic crisis. Inhibition of CaMKII exacerbates the accumulation of aggregated misfolded proteins and paraptosis induced by proteasome inhibitors. Based on these findings, we validate that combined targeting of proteasome and CaMKII accelerates tumor cell death and enhances the efficacy of proteasome inhibitors in tumor treatment. Our data unveil a new proteasomal inhibition-induced misfolded protein quality control mechanism and propose a novel therapeutic intervention for proteasome inhibitor-mediated tumor treatment.
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Affiliation(s)
- Chenliang Zhang
- Division of Abdominal Tumor Multimodality Treatment, Department of Medical Oncology, Cancer Center and Laboratory of Molecular Targeted Therapy in Oncology, West China Hospital, Sichuan University, Chengdu, Sichuan Province, China
| | - Huanji Xu
- Division of Abdominal Tumor Multimodality Treatment, Department of Medical Oncology, Cancer Center, West China Hospital, Sichuan University, Chengdu, Sichuan Province, China
| | - Qiulin Tang
- Division of Abdominal Tumor Multimodality Treatment, Department of Medical Oncology, Cancer Center and Laboratory of Molecular Targeted Therapy in Oncology, West China Hospital, Sichuan University, Chengdu, Sichuan Province, China
| | - Yichun Duan
- Division of Abdominal Tumor Multimodality Treatment, Department of Medical Oncology, Cancer Center, West China Hospital, Sichuan University, Chengdu, Sichuan Province, China
| | - Hongwei Xia
- Division of Abdominal Tumor Multimodality Treatment, Department of Medical Oncology, Cancer Center and Laboratory of Molecular Targeted Therapy in Oncology, West China Hospital, Sichuan University, Chengdu, Sichuan Province, China
| | - Huixi Huang
- Division of Abdominal Tumor Multimodality Treatment, Department of Medical Oncology, Cancer Center and Laboratory of Molecular Targeted Therapy in Oncology, West China Hospital, Sichuan University, Chengdu, Sichuan Province, China
| | - Di Ye
- Division of Abdominal Tumor Multimodality Treatment, Department of Medical Oncology, Cancer Center, West China Hospital, Sichuan University, Chengdu, Sichuan Province, China
| | - Feng Bi
- Division of Abdominal Tumor Multimodality Treatment, Department of Medical Oncology, Cancer Center and Laboratory of Molecular Targeted Therapy in Oncology, West China Hospital, Sichuan University, Chengdu, Sichuan Province, China.
- Division of Abdominal Tumor Multimodality Treatment, Department of Medical Oncology, Cancer Center, West China Hospital, Sichuan University, Chengdu, Sichuan Province, China.
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3
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Haakonsen DL, Heider M, Ingersoll AJ, Vodehnal K, Witus SR, Uenaka T, Wernig M, Rapé M. Stress response silencing by an E3 ligase mutated in neurodegeneration. Nature 2024; 626:874-880. [PMID: 38297121 PMCID: PMC10881396 DOI: 10.1038/s41586-023-06985-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2023] [Accepted: 12/15/2023] [Indexed: 02/02/2024]
Abstract
Stress response pathways detect and alleviate adverse conditions to safeguard cell and tissue homeostasis, yet their prolonged activation induces apoptosis and disrupts organismal health1-3. How stress responses are turned off at the right time and place remains poorly understood. Here we report a ubiquitin-dependent mechanism that silences the cellular response to mitochondrial protein import stress. Crucial to this process is the silencing factor of the integrated stress response (SIFI), a large E3 ligase complex mutated in ataxia and in early-onset dementia that degrades both unimported mitochondrial precursors and stress response components. By recognizing bifunctional substrate motifs that equally encode protein localization and stability, the SIFI complex turns off a general stress response after a specific stress event has been resolved. Pharmacological stress response silencing sustains cell survival even if stress resolution failed, which underscores the importance of signal termination and provides a roadmap for treating neurodegenerative diseases caused by mitochondrial import defects.
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Affiliation(s)
- Diane L Haakonsen
- Department of Molecular and Cell Biology, University of California at Berkeley, Berkeley, CA, USA
- Howard Hughes Medical Institute, University of California at Berkeley, Berkeley, CA, USA
| | - Michael Heider
- Department of Molecular and Cell Biology, University of California at Berkeley, Berkeley, CA, USA
| | - Andrew J Ingersoll
- Department of Molecular and Cell Biology, University of California at Berkeley, Berkeley, CA, USA
| | - Kayla Vodehnal
- Institute for Stem Cell Biology and Regenerative Medicine, Stanford University School of Medicine, Stanford, CA, USA
- Department of Pathology, Stanford University School of Medicine, Stanford, CA, USA
| | - Samuel R Witus
- Department of Molecular and Cell Biology, University of California at Berkeley, Berkeley, CA, USA
- Howard Hughes Medical Institute, University of California at Berkeley, Berkeley, CA, USA
| | - Takeshi Uenaka
- Institute for Stem Cell Biology and Regenerative Medicine, Stanford University School of Medicine, Stanford, CA, USA
- Department of Pathology, Stanford University School of Medicine, Stanford, CA, USA
| | - Marius Wernig
- Institute for Stem Cell Biology and Regenerative Medicine, Stanford University School of Medicine, Stanford, CA, USA
- Department of Pathology, Stanford University School of Medicine, Stanford, CA, USA
| | - Michael Rapé
- Department of Molecular and Cell Biology, University of California at Berkeley, Berkeley, CA, USA.
- Howard Hughes Medical Institute, University of California at Berkeley, Berkeley, CA, USA.
- California Institute for Quantitative Biosciences (QB3), University of California at Berkeley, Berkeley, CA, USA.
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4
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Ziakova K, Kovalska M, Pilchova I, Dibdiakova K, Brodnanova M, Pokusa M, Kalenska D, Racay P. Involvement of Proteasomal and Endoplasmic Reticulum Stress in Neurodegeneration After Global Brain Ischemia. Mol Neurobiol 2023; 60:6316-6329. [PMID: 37452223 PMCID: PMC10533597 DOI: 10.1007/s12035-023-03479-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2023] [Accepted: 07/03/2023] [Indexed: 07/18/2023]
Abstract
A brief period of transient global brain ischemia leads to selective ischemic neurodegeneration associated with death of hippocampal CA1 pyramidal neurons days after reperfusion. The mechanism of such selective and delayed neurodegeneration is still uncertain. Our work aimed to study the involvement of proteasomal and endoplasmic reticulum (ER) stress in ischemic neurodegeneration. We have performed laser scanning confocal microscopy analysis of brain slices from control and experimental animals that underwent global brain ischemia for 15 min and varying times of reperfusion. We have focused on ubiquitin, PUMA, a proapoptotic protein of the Bcl-2 family overexpressed in response to both proteasomal and ER stress, and p53, which controls expression of PUMA. We have also examined the expression of HRD1, an E3 ubiquitin ligase that was shown to be overexpressed after ER stress. We have also examined potential crosstalk between proteasomal and ER stress using cellular models of both proteasomal and ER stress. We demonstrate that global brain ischemia is associated with an appearance of distinct immunoreactivity of ubiquitin, PUMA and p53 in pyramidal neurons of the CA1 layer of the hippocampus 72 h after ischemic insults. Such changes correlate with a delay and selectivity of ischemic neurodegeneration. Immunoreactivity of HRD1 observed in all investigated regions of rat brain was transiently absent in both CA1 and CA3 pyramidal neurones 24 h after ischemia in the hippocampus, which does not correlate with a delay and selectivity of ischemic neurodegeneration. We do not document significant crosstalk between proteasomal and ER stress. Our results favour dysfunction of the ubiquitin proteasome system and consequent p53-induced expression of PUMA as the main mechanisms responsible for selective and delayed degeneration of pyramidal neurons of the hippocampal CA1 layer in response to global brain ischemia.
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Affiliation(s)
- Katarina Ziakova
- Biomedical Center, Jessenius Faculty of Medicine in Martin, Comenius University in Bratislava, Martin, Slovakia
| | - Maria Kovalska
- Department of Histology and Embryology, Jessenius Faculty of Medicine in Martin, Comenius University in Bratislava, Martin, Slovakia
| | - Ivana Pilchova
- Biomedical Center, Jessenius Faculty of Medicine in Martin, Comenius University in Bratislava, Martin, Slovakia
| | - Katarina Dibdiakova
- Department of Medical Biochemistry, Jessenius Faculty of Medicine in Martin, Comenius University in Bratislava, Mala Hora 4D, SK-03601, Martin, Slovak Republic
| | - Maria Brodnanova
- Biomedical Center, Jessenius Faculty of Medicine in Martin, Comenius University in Bratislava, Martin, Slovakia
| | - Michal Pokusa
- Biomedical Center, Jessenius Faculty of Medicine in Martin, Comenius University in Bratislava, Martin, Slovakia
| | - Dagmar Kalenska
- Department of Anatomy, Jessenius Faculty of Medicine in Martin, Comenius University in Bratislava, Martin, Slovakia
| | - Peter Racay
- Department of Medical Biochemistry, Jessenius Faculty of Medicine in Martin, Comenius University in Bratislava, Mala Hora 4D, SK-03601, Martin, Slovak Republic.
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5
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Cagnetta R, Flanagan JG, Sonenberg N. Control of Selective mRNA Translation in Neuronal Subcellular Compartments in Health and Disease. J Neurosci 2023; 43:7247-7263. [PMID: 37914402 PMCID: PMC10621772 DOI: 10.1523/jneurosci.2240-22.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2022] [Revised: 04/28/2023] [Accepted: 05/02/2023] [Indexed: 11/03/2023] Open
Abstract
In multiple cell types, mRNAs are transported to subcellular compartments, where local translation enables rapid, spatially localized, and specific responses to external stimuli. Mounting evidence has uncovered important roles played by local translation in vivo in axon survival, axon regeneration, and neural wiring, as well as strong links between dysregulation of local translation and neurologic disorders. Omic studies have revealed that >1000 mRNAs are present and can be selectively locally translated in the presynaptic and postsynaptic compartments from development to adulthood in vivo A large proportion of the locally translated mRNAs is specifically upregulated or downregulated in response to distinct extracellular signals. Given that the local translatome is large, selectively translated, and cue-specifically remodeled, a fundamental question concerns how selective translation is achieved locally. Here, we review the emerging regulatory mechanisms of local selective translation in neuronal subcellular compartments, their mRNA targets, and their orchestration. We discuss mechanisms of local selective translation that remain unexplored. Finally, we describe clinical implications and potential therapeutic strategies in light of the latest advances in gene therapy.
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Affiliation(s)
- Roberta Cagnetta
- Department of Biochemistry and Goodman Cancer Institute, McGill University, Montreal, Quebec H3A 1A3, Canada
| | - John G Flanagan
- Department of Cell Biology and Program in Neuroscience, Harvard Medical School, Boston, Massachusetts 02115
| | - Nahum Sonenberg
- Department of Biochemistry and Goodman Cancer Institute, McGill University, Montreal, Quebec H3A 1A3, Canada
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6
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Hooshmandi M, Sharma V, Thörn Perez C, Sood R, Krimbacher K, Wong C, Lister KC, Ureña Guzmán A, Bartley TD, Rocha C, Maussion G, Nadler E, Roque PM, Gantois I, Popic J, Lévesque M, Kaufman RJ, Avoli M, Sanz E, Nader K, Hagerman RJ, Durcan TM, Costa-Mattioli M, Prager-Khoutorsky M, Lacaille JC, Martinez-Cerdeno V, Gibson JR, Huber KM, Sonenberg N, Gkogkas CG, Khoutorsky A. Excitatory neuron-specific suppression of the integrated stress response contributes to autism-related phenotypes in fragile X syndrome. Neuron 2023; 111:3028-3040.e6. [PMID: 37473758 PMCID: PMC10592416 DOI: 10.1016/j.neuron.2023.06.017] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2022] [Revised: 05/11/2023] [Accepted: 06/22/2023] [Indexed: 07/22/2023]
Abstract
Dysregulation of protein synthesis is one of the key mechanisms underlying autism spectrum disorder (ASD). However, the role of a major pathway controlling protein synthesis, the integrated stress response (ISR), in ASD remains poorly understood. Here, we demonstrate that the main arm of the ISR, eIF2α phosphorylation (p-eIF2α), is suppressed in excitatory, but not inhibitory, neurons in a mouse model of fragile X syndrome (FXS; Fmr1-/y). We further show that the decrease in p-eIF2α is mediated via activation of mTORC1. Genetic reduction of p-eIF2α only in excitatory neurons is sufficient to increase general protein synthesis and cause autism-like behavior. In Fmr1-/y mice, restoration of p-eIF2α solely in excitatory neurons reverses elevated protein synthesis and rescues autism-related phenotypes. Thus, we reveal a previously unknown causal relationship between excitatory neuron-specific translational control via the ISR pathway, general protein synthesis, and core phenotypes reminiscent of autism in a mouse model of FXS.
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Affiliation(s)
- Mehdi Hooshmandi
- Department of Anesthesia and Faculty of Dental Medicine and Oral Health Sciences, McGill University, Montréal, QC, Canada
| | - Vijendra Sharma
- Department of Biochemistry, McGill University, Montréal, QC, Canada
| | - Carolina Thörn Perez
- Department of Anesthesia and Faculty of Dental Medicine and Oral Health Sciences, McGill University, Montréal, QC, Canada
| | - Rapita Sood
- Department of Biochemistry, McGill University, Montréal, QC, Canada
| | - Konstanze Krimbacher
- Department of Pharmacology, Medical University Innsbruck, 6020 Innsbruck, Austria
| | - Calvin Wong
- Department of Anesthesia and Faculty of Dental Medicine and Oral Health Sciences, McGill University, Montréal, QC, Canada
| | - Kevin C Lister
- Department of Anesthesia and Faculty of Dental Medicine and Oral Health Sciences, McGill University, Montréal, QC, Canada
| | - Alba Ureña Guzmán
- Department of Anesthesia and Faculty of Dental Medicine and Oral Health Sciences, McGill University, Montréal, QC, Canada
| | - Trevor D Bartley
- Department of Pathology and Laboratory Medicine, UC Davis School of Medicine, Institute for Pediatric Regenerative Medicine and Shriners Hospitals for Children of Northern California, MIND Institute, UC Davis Medical Center, Sacramento, CA, USA
| | - Cecilia Rocha
- The Neuro's Early Drug Discovery Unit (EDDU), Department of Neurology and Neurosurgery, Montreal Neurological Institute-Hospital, McGill University, Montréal, QC, Canada
| | - Gilles Maussion
- The Neuro's Early Drug Discovery Unit (EDDU), Department of Neurology and Neurosurgery, Montreal Neurological Institute-Hospital, McGill University, Montréal, QC, Canada
| | - Emma Nadler
- Department of Anesthesia and Faculty of Dental Medicine and Oral Health Sciences, McGill University, Montréal, QC, Canada
| | - Patricia Margarita Roque
- Department of Anesthesia and Faculty of Dental Medicine and Oral Health Sciences, McGill University, Montréal, QC, Canada
| | - Ilse Gantois
- Department of Biochemistry, McGill University, Montréal, QC, Canada
| | - Jelena Popic
- Department of Biochemistry, McGill University, Montréal, QC, Canada
| | - Maxime Lévesque
- Montreal Neurological Institute-Hospital, Departments of Neurology & Neurosurgery and of Physiology, McGill University, Montréal, QC, Canada
| | - Randal J Kaufman
- Degenerative Diseases Program, Center for Genetic Disorders and Aging Research, Sanford-Burnham-Prebys Medical Discovery Institute, La Jolla, CA 92037, USA
| | - Massimo Avoli
- Montreal Neurological Institute-Hospital, Departments of Neurology & Neurosurgery and of Physiology, McGill University, Montréal, QC, Canada
| | - Elisenda Sanz
- Department of Cell Biology, Physiology and Immunology, and Neuroscience Institute, Universitat Autònoma de Barcelona, Bellaterra, Spain
| | - Karim Nader
- Department of Psychology, Faculty of Science, McGill University, Montréal, QC, Canada
| | - Randi Jenssen Hagerman
- MIND Institute and Department of Pediatrics, University of California at Davis Medical Center, Sacramento, CA, USA
| | - Thomas M Durcan
- The Neuro's Early Drug Discovery Unit (EDDU), Department of Neurology and Neurosurgery, Montreal Neurological Institute-Hospital, McGill University, Montréal, QC, Canada
| | | | | | - Jean-Claude Lacaille
- Department of Neurosciences, Center for Interdisciplinary Research on Brain and Learning, and Research Group on Neural Signaling and Circuitry, Université de Montréal, Montréal, QC, Canada
| | - Veronica Martinez-Cerdeno
- Department of Pathology and Laboratory Medicine, UC Davis School of Medicine, Institute for Pediatric Regenerative Medicine and Shriners Hospitals for Children of Northern California, MIND Institute, UC Davis Medical Center, Sacramento, CA, USA
| | - Jay R Gibson
- University of Texas Southwestern Medical Center at Dallas, Department of Neuroscience, Dallas, TX 75390-9111, USA
| | - Kimberly M Huber
- University of Texas Southwestern Medical Center at Dallas, Department of Neuroscience, Dallas, TX 75390-9111, USA
| | - Nahum Sonenberg
- Department of Biochemistry, McGill University, Montréal, QC, Canada.
| | - Christos G Gkogkas
- Biomedical Research Institute, Foundation for Research and Technology-Hellas, University Campus, 45110 Ioannina, Greece.
| | - Arkady Khoutorsky
- Department of Anesthesia and Faculty of Dental Medicine and Oral Health Sciences, McGill University, Montréal, QC, Canada; Alan Edwards Centre for Research on Pain, McGill University, Montréal, QC, Canada.
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7
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Chinchankar MN, Taylor WB, Ko SH, Apple EC, Rodriguez KA, Chen L, Fisher AL. A novel endoplasmic reticulum adaptation is critical for the long-lived Caenorhabditis elegans rpn-10 proteasomal mutant. BIOCHIMICA ET BIOPHYSICA ACTA. GENE REGULATORY MECHANISMS 2023; 1866:194957. [PMID: 37355092 PMCID: PMC10528105 DOI: 10.1016/j.bbagrm.2023.194957] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/16/2023] [Revised: 04/24/2023] [Accepted: 06/14/2023] [Indexed: 06/26/2023]
Abstract
The loss of proteostasis due to reduced efficiency of protein degradation pathways plays a key role in multiple age-related diseases and is a hallmark of the aging process. Paradoxically, we have previously reported that the Caenorhabditis elegans rpn-10(ok1865) mutant, which lacks the RPN-10/RPN10/PSMD4 subunit of the 19S regulatory particle of the 26S proteasome, exhibits enhanced cytosolic proteostasis, elevated stress resistance and extended lifespan, despite possessing reduced proteasome function. However, the response of this mutant against threats to endoplasmic reticulum (ER) homeostasis and proteostasis was unknown. Here, we find that the rpn-10 mutant is highly ER stress resistant compared to the wildtype. Under unstressed conditions, the ER unfolded protein response (UPR) is activated in the rpn-10 mutant as signified by increased xbp-1 splicing. This primed response appears to alter ER homeostasis through the upregulated expression of genes involved in ER protein quality control (ERQC), including those in the ER-associated protein degradation (ERAD) pathway. Pertinently, we find that ERQC is critical for the rpn-10 mutant longevity. These changes also alter ER proteostasis, as studied using the C. elegans alpha-1 antitrypsin (AAT) deficiency model, which comprises an intestinal ER-localised transgenic reporter of an aggregation-prone form of AAT called ATZ. The rpn-10 mutant shows a significant reduction in the accumulation of the ATZ reporter, thus indicating that its ER proteostasis is augmented. Via a genetic screen for suppressors of decreased ATZ aggregation in the rpn-10 mutant, we then identified ecps-2/H04D03.3, a novel ortholog of the proteasome-associated adaptor and scaffold protein ECM29/ECPAS. We further show that ecps-2 is required for improved ER proteostasis as well as lifespan extension of the rpn-10 mutant. Thus, we propose that ECPS-2-proteasome functional interactions, alongside additional putative molecular processes, contribute to a novel ERQC adaptation which underlies the superior proteostasis and longevity of the rpn-10 mutant.
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Affiliation(s)
- Meghna N Chinchankar
- Barshop Institute for Longevity and Aging Studies, UT Health San Antonio (UTHSCSA), SA, TX, United States of America; Department of Cell Systems and Anatomy, UTHSCSA, SA, TX, United States of America
| | - William B Taylor
- Division of Geriatrics, Gerontology, and Palliative Medicine, Department of Internal Medicine, University of Nebraska Medical Center, Omaha, NE, United States of America
| | - Su-Hyuk Ko
- Barshop Institute for Longevity and Aging Studies, UT Health San Antonio (UTHSCSA), SA, TX, United States of America; Department of Cell Systems and Anatomy, UTHSCSA, SA, TX, United States of America
| | - Ellen C Apple
- Barshop Institute for Longevity and Aging Studies, UT Health San Antonio (UTHSCSA), SA, TX, United States of America; Department of Cell Systems and Anatomy, UTHSCSA, SA, TX, United States of America
| | - Karl A Rodriguez
- Department of Cell Systems and Anatomy, UTHSCSA, SA, TX, United States of America
| | - Lizhen Chen
- Barshop Institute for Longevity and Aging Studies, UT Health San Antonio (UTHSCSA), SA, TX, United States of America; Department of Cell Systems and Anatomy, UTHSCSA, SA, TX, United States of America
| | - Alfred L Fisher
- Division of Geriatrics, Gerontology, and Palliative Medicine, Department of Internal Medicine, University of Nebraska Medical Center, Omaha, NE, United States of America.
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8
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Storkebaum E, Rosenblum K, Sonenberg N. Messenger RNA Translation Defects in Neurodegenerative Diseases. Reply. N Engl J Med 2023; 388:2110-2111. [PMID: 37256994 DOI: 10.1056/nejmc2304387] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Affiliation(s)
- Erik Storkebaum
- Donders Institute for Brain, Cognition, and Behavior, Nijmegen, the Netherlands
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9
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Kim H, Moore CM, Mestre-Fos S, Hanna DA, Williams LD, Reddi AR, Torres MP. Depletion assisted hemin affinity (DAsHA) proteomics reveals an expanded landscape of heme-binding proteins in the human proteome. Metallomics 2023; 15:6994529. [PMID: 36669767 PMCID: PMC10022665 DOI: 10.1093/mtomcs/mfad004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2022] [Accepted: 01/19/2023] [Indexed: 01/22/2023]
Abstract
Heme b (iron protoporphyrin IX) plays important roles in biology as a metallocofactor and signaling molecule. However, the targets of heme signaling and the network of proteins that mediate the exchange of heme from sites of synthesis or uptake to heme dependent or regulated proteins are poorly understood. Herein, we describe a quantitative mass spectrometry (MS)-based chemoproteomics strategy to identify exchange labile hemoproteins in human embryonic kidney HEK293 cells that may be relevant to heme signaling and trafficking. The strategy involves depleting endogenous heme with the heme biosynthetic inhibitor succinylacetone (SA), leaving putative heme-binding proteins in their apo-state, followed by the capture of those proteins using hemin-agarose resin, and finally elution and identification by MS. By identifying only those proteins that interact with high specificity to hemin-agarose relative to control beaded agarose in an SA-dependent manner, we have expanded the number of proteins and ontologies that may be involved in binding and buffering labile heme or are targets of heme signaling. Notably, these include proteins involved in chromatin remodeling, DNA damage response, RNA splicing, cytoskeletal organization, and vesicular trafficking, many of which have been associated with heme through complementary studies published recently. Taken together, these results provide support for the emerging role of heme in an expanded set of cellular processes from genome integrity to protein trafficking and beyond.
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Affiliation(s)
- Hyojung Kim
- School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, GA 30332, USA
| | - Courtney M Moore
- School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, GA 30332, USA
| | - Santi Mestre-Fos
- School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, GA 30332, USA
| | - David A Hanna
- School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, GA 30332, USA
| | - Loren Dean Williams
- School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, GA 30332, USA
| | - Amit R Reddi
- Correspondence: Amit R. Reddi, School of Chemistry and Biochemistry, Georgia Institute of Technology, 950 Atlantic Dr. Atlanta, GA 30033. E-mail:
| | - Matthew P Torres
- Correspondence: Matthew P. Torres, School of Biological Sciences, Georgia Institute of Technology, 950 Atlantic Dr. Atlanta, GA 30033. E-mail:
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10
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Louros SR, Seo SS, Maio B, Martinez-Gonzalez C, Gonzalez-Lozano MA, Muscas M, Verity NC, Wills JC, Li KW, Nolan MF, Osterweil EK. Excessive proteostasis contributes to pathology in fragile X syndrome. Neuron 2023; 111:508-525.e7. [PMID: 36495869 DOI: 10.1016/j.neuron.2022.11.012] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2021] [Revised: 09/06/2022] [Accepted: 11/16/2022] [Indexed: 12/13/2022]
Abstract
In fragile X syndrome (FX), the leading monogenic cause of autism, excessive neuronal protein synthesis is a core pathophysiology; however, an overall increase in protein expression is not observed. Here, we tested whether excessive protein synthesis drives a compensatory rise in protein degradation that is protective for FX mouse model (Fmr1-/y) neurons. Surprisingly, although we find a significant increase in protein degradation through ubiquitin proteasome system (UPS), this contributes to pathological changes. Normalizing proteasome activity with bortezomib corrects excessive hippocampal protein synthesis and hyperactivation of neurons in the inferior colliculus (IC) in response to auditory stimulation. Moreover, systemic administration of bortezomib significantly reduces the incidence and severity of audiogenic seizures (AGS) in the Fmr1-/y mouse, as does genetic reduction of proteasome, specifically in the IC. Together, these results identify excessive activation of the UPS pathway in Fmr1-/y neurons as a contributor to multiple phenotypes that can be targeted for therapeutic intervention.
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Affiliation(s)
- Susana R Louros
- Centre for Discovery Brain Sciences, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh EH8 9XD, UK; Simons Initiative for the Developing Brain, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh EH8 9XD, UK
| | - Sang S Seo
- Centre for Discovery Brain Sciences, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh EH8 9XD, UK; Simons Initiative for the Developing Brain, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh EH8 9XD, UK
| | - Beatriz Maio
- Centre for Discovery Brain Sciences, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh EH8 9XD, UK; Simons Initiative for the Developing Brain, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh EH8 9XD, UK
| | - Cristina Martinez-Gonzalez
- Centre for Discovery Brain Sciences, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh EH8 9XD, UK; Simons Initiative for the Developing Brain, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh EH8 9XD, UK
| | - Miguel A Gonzalez-Lozano
- Department of Molecular and Cellular Neurobiology, Centre for Neurogenomics and Cognitive Research, Vrije Universiteit Amsterdam, Amsterdam, the Netherlands
| | - Melania Muscas
- Centre for Discovery Brain Sciences, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh EH8 9XD, UK; Simons Initiative for the Developing Brain, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh EH8 9XD, UK
| | - Nick C Verity
- Centre for Discovery Brain Sciences, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh EH8 9XD, UK; Simons Initiative for the Developing Brain, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh EH8 9XD, UK
| | - Jimi C Wills
- CRUK Edinburgh Centre, Institute of Genetics and Cancer, University of Edinburgh, Edinburgh, UK
| | - Ka Wan Li
- Department of Molecular and Cellular Neurobiology, Centre for Neurogenomics and Cognitive Research, Vrije Universiteit Amsterdam, Amsterdam, the Netherlands
| | - Matthew F Nolan
- Centre for Discovery Brain Sciences, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh EH8 9XD, UK; Simons Initiative for the Developing Brain, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh EH8 9XD, UK
| | - Emily K Osterweil
- Centre for Discovery Brain Sciences, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh EH8 9XD, UK; Simons Initiative for the Developing Brain, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh EH8 9XD, UK.
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11
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Andrysik Z, Sullivan KD, Kieft JS, Espinosa JM. PPM1D suppresses p53-dependent transactivation and cell death by inhibiting the Integrated Stress Response. Nat Commun 2022; 13:7400. [PMID: 36456590 PMCID: PMC9715646 DOI: 10.1038/s41467-022-35089-5] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2022] [Accepted: 11/17/2022] [Indexed: 12/03/2022] Open
Abstract
The p53 transcription factor is a master regulator of cellular stress responses inhibited by repressors such as MDM2 and the phosphatase PPM1D. Activation of p53 with pharmacological inhibitors of its repressors is being tested in clinical trials for cancer therapy, but efficacy has been limited by poor induction of tumor cell death. We demonstrate that dual inhibition of MDM2 and PPM1D induces apoptosis in multiple cancer cell types via amplification of the p53 transcriptional program through the eIF2α-ATF4 pathway. PPM1D inhibition induces phosphorylation of eIF2α, ATF4 accumulation, and ATF4-dependent enhancement of p53-dependent transactivation upon MDM2 inhibition. Dual inhibition of p53 repressors depletes heme and induces HRI-dependent eIF2α phosphorylation. Pharmacological induction of eIF2α phosphorylation synergizes with MDM2 inhibition to induce cell death and halt tumor growth in mice. These results demonstrate that PPM1D inhibits both the p53 network and the integrated stress response controlled by eIF2α-ATF4, with clear therapeutic implications.
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Affiliation(s)
- Zdenek Andrysik
- Linda Crnic Institute for Down Syndrome, University of Colorado Anschutz Medical Campus, Aurora, CO, 80045, USA.
- Department of Pharmacology, University of Colorado Anschutz Medical Campus, Aurora, CO, 80045, USA.
| | - Kelly D Sullivan
- Linda Crnic Institute for Down Syndrome, University of Colorado Anschutz Medical Campus, Aurora, CO, 80045, USA
- Department of Pediatrics, Section of Developmental Biology, University of Colorado Anschutz Medical Campus, Aurora, CO, 80045, USA
| | - Jeffrey S Kieft
- Department of Biochemistry and Molecular Genetics and RNA Bioscience Initiative, University of Colorado Anschutz Medical Campus, Aurora, CO, 80045, USA
| | - Joaquin M Espinosa
- Linda Crnic Institute for Down Syndrome, University of Colorado Anschutz Medical Campus, Aurora, CO, 80045, USA.
- Department of Pharmacology, University of Colorado Anschutz Medical Campus, Aurora, CO, 80045, USA.
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12
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Marlin E, Viu-Idocin C, Arrasate M, Aragón T. The Role and Therapeutic Potential of the Integrated Stress Response in Amyotrophic Lateral Sclerosis. Int J Mol Sci 2022; 23:ijms23147823. [PMID: 35887167 PMCID: PMC9321386 DOI: 10.3390/ijms23147823] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2022] [Revised: 07/08/2022] [Accepted: 07/09/2022] [Indexed: 02/06/2023] Open
Abstract
In amyotrophic lateral sclerosis (ALS) patients, loss of cellular homeostasis within cortical and spinal cord motor neurons triggers the activation of the integrated stress response (ISR), an intracellular signaling pathway that remodels translation and promotes a gene expression program aimed at coping with stress. Beyond its neuroprotective role, under regimes of chronic or excessive stress, ISR can also promote cell/neuronal death. Given the two-edged sword nature of ISR, many experimental attempts have tried to establish the therapeutic potential of ISR enhancement or inhibition in ALS. This review discusses the complex interplay between ISR and disease progression in different models of ALS, as well as the opportunities and limitations of ISR modulation in the hard quest to find an effective therapy for ALS.
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Affiliation(s)
- Elías Marlin
- Neuroscience Program, Center for Applied Medical Research (CIMA), University of Navarra, 31008 Pamplona, Spain;
- Gene Therapy and Regulation of Gene Expression Program, Center for Applied Medical Research (CIMA), University of Navarra, 31008 Pamplona, Spain
- School of Medicine, University of Navarra, 31008 Pamplona, Spain
- Neuroscience Department, Navarra Institute for Health Research (IdiSNA), University of Navarra, 31008 Pamplona, Spain
| | | | - Montserrat Arrasate
- Neuroscience Program, Center for Applied Medical Research (CIMA), University of Navarra, 31008 Pamplona, Spain;
- School of Medicine, University of Navarra, 31008 Pamplona, Spain
- Neuroscience Department, Navarra Institute for Health Research (IdiSNA), University of Navarra, 31008 Pamplona, Spain
- Correspondence: (M.A.); (T.A.)
| | - Tomás Aragón
- Gene Therapy and Regulation of Gene Expression Program, Center for Applied Medical Research (CIMA), University of Navarra, 31008 Pamplona, Spain
- Neuroscience Department, Navarra Institute for Health Research (IdiSNA), University of Navarra, 31008 Pamplona, Spain
- Correspondence: (M.A.); (T.A.)
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13
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Wolzak K, Nölle A, Farina M, Abbink TE, van der Knaap MS, Verhage M, Scheper W. Neuron-specific translational control shift ensures proteostatic resilience during ER stress. EMBO J 2022; 41:e110501. [PMID: 35791631 PMCID: PMC9379547 DOI: 10.15252/embj.2021110501] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2021] [Revised: 06/06/2022] [Accepted: 06/09/2022] [Indexed: 11/30/2022] Open
Abstract
Proteostasis is essential for cellular survival and particularly important for highly specialised post‐mitotic cells such as neurons. Transient reduction in protein synthesis by protein kinase R‐like endoplasmic reticulum (ER) kinase (PERK)‐mediated phosphorylation of eukaryotic translation initiation factor 2α (p‐eIF2α) is a major proteostatic survival response during ER stress. Paradoxically, neurons are remarkably tolerant to PERK dysfunction, which suggests the existence of cell type‐specific mechanisms that secure proteostatic stress resilience. Here, we demonstrate that PERK‐deficient neurons, unlike other cell types, fully retain the capacity to control translation during ER stress. We observe rescaling of the ATF4 response, while the reduction in protein synthesis is fully retained. We identify two molecular pathways that jointly drive translational control in PERK‐deficient neurons. Haem‐regulated inhibitor (HRI) mediates p‐eIF2α and the ATF4 response and is complemented by the tRNA cleaving RNase angiogenin (ANG) to reduce protein synthesis. Overall, our study elucidates an intricate back‐up mechanism to ascertain translational control during ER stress in neurons that provides a mechanistic explanation for the thus far unresolved observation of neuronal resilience to proteostatic stress.
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Affiliation(s)
- Kimberly Wolzak
- Department of Functional Genomics, Faculty of Science, Center for Neurogenomics and Cognitive Research (CNCR), Vrije Universiteit (VU) Amsterdam, Amsterdam, The Netherlands.,Functional Genomics Section, Department of Human Genetics, Amsterdam University Medical Centers (UMC) Location Vrije Universiteit, Amsterdam, The Netherlands
| | - Anna Nölle
- Department of Pathology, Amsterdam University Medical Centers (UMC) Location Vrije Universiteit, Amsterdam, The Netherlands
| | - Margherita Farina
- Department of Functional Genomics, Faculty of Science, Center for Neurogenomics and Cognitive Research (CNCR), Vrije Universiteit (VU) Amsterdam, Amsterdam, The Netherlands
| | - Truus Em Abbink
- Department of Child Neurology, Amsterdam University Medical Centers (UMC) Location Vrije Universiteit, Amsterdam, The Netherlands
| | - Marjo S van der Knaap
- Department of Functional Genomics, Faculty of Science, Center for Neurogenomics and Cognitive Research (CNCR), Vrije Universiteit (VU) Amsterdam, Amsterdam, The Netherlands.,Department of Child Neurology, Amsterdam University Medical Centers (UMC) Location Vrije Universiteit, Amsterdam, The Netherlands
| | - Matthijs Verhage
- Department of Functional Genomics, Faculty of Science, Center for Neurogenomics and Cognitive Research (CNCR), Vrije Universiteit (VU) Amsterdam, Amsterdam, The Netherlands.,Functional Genomics Section, Department of Human Genetics, Amsterdam University Medical Centers (UMC) Location Vrije Universiteit, Amsterdam, The Netherlands
| | - Wiep Scheper
- Department of Functional Genomics, Faculty of Science, Center for Neurogenomics and Cognitive Research (CNCR), Vrije Universiteit (VU) Amsterdam, Amsterdam, The Netherlands.,Functional Genomics Section, Department of Human Genetics, Amsterdam University Medical Centers (UMC) Location Vrije Universiteit, Amsterdam, The Netherlands
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14
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Yerlikaya A. Heme-regulated inhibitor: an overlooked eIF2α kinase in cancer investigations. Med Oncol 2022; 39:73. [PMID: 35568791 DOI: 10.1007/s12032-022-01668-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2021] [Accepted: 01/24/2022] [Indexed: 10/18/2022]
Abstract
Heme-regulated inhibitor (HRI) kinase is a serine-threonine kinase, controlling the initiation of protein synthesis via phosphorylating α subunit of eIF2 on serine 51 residue, mainly in response to heme deprivation in erythroid cells. However, recent studies showed that HRI is also activated by several diverse signals, causing dysregulations in intracellular homeostatic mechanisms in non-erythroid cells. For instance, it was reported that the decrease in protein synthesis upon the 26S proteasomal inhibition by MG132 or bortezomib is mediated by increased eIF2α phosphorylation in an HRI-dependent manner in mouse embryonic fibroblast cells. The increase in eIF2α phosphorylation level through the activation of HRI upon 26S proteasomal inhibition is believed to protect cells against the buildup of misfolded and ubiquitinated proteins, having the potential to trigger the apoptotic response. In contrast, prolonged and sustained HRI-mediated eIF2α phosphorylation can induce cell death, which may involve ATF4 and CHOP expression. Altogether, these studies suggest that HRI-mediated eIF2α phosphorylation may be cytoprotective or cytotoxic depending on the cells, type, and duration of pharmacological agents used. It is thus hypothesized that both HRI activators, inducing eIF2α phosphorylation or HRI inhibitors causing disturbances in eIF2α phosphorylation, may be effective as novel strategies in cancer treatment if the balance in eIF2α phosphorylation is shifted in favor of autophagic or apoptotic response in cancer cells. It is here aimed to review the role of HRI in various biological mechanisms as well as the therapeutic potentials of recently developed HRI activators and inhibitors, targeting eIF2α phosphorylation in cancer cells.
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Affiliation(s)
- Azmi Yerlikaya
- Department of Medical Biology, Faculty of Medicine, Kutahya Health Sciences University, Kutahya, Turkey.
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15
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Oliveira MM, Klann E. eIF2-dependent translation initiation: Memory consolidation and disruption in Alzheimer's disease. Semin Cell Dev Biol 2022; 125:101-109. [PMID: 34304995 PMCID: PMC8782933 DOI: 10.1016/j.semcdb.2021.07.009] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2021] [Revised: 06/20/2021] [Accepted: 07/12/2021] [Indexed: 01/05/2023]
Abstract
Memory storage is a conserved survivability feature, present in virtually any complex species. During the last few decades, much effort has been devoted to understanding how memories are formed and which molecular switches define whether a memory should be stored for a short or a long period of time. Among these, de novo protein synthesis is known to be required for the conversion of short- to long-term memory. There are a number translational control pathways involved in synaptic plasticity and memory consolidation, including the phosphorylation of the eukaryotic initiation factor 2 alpha (eIF2α), which has emerged as a critical molecular switch for long-term memory consolidation. In this review, we discuss findings pertaining to the requirement of de novo protein synthesis to memory formation, how local dendritic and axonal translation is regulated in neurons, and how these can influence memory consolidation. We also highlight the importance of eIF2α-dependent translation initiation to synaptic plasticity and memory formation. Finally, we contextualize how aberrant phosphorylation of eIF2α contributes to Alzheimer's disease (AD) pathology and how preventing disruption of eIF2-dependent translation may be a therapeutic avenue for preventing and/or restoring memory loss in AD.
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Affiliation(s)
| | - Eric Klann
- Center for Neural Science, New York University, New York, NY, USA; NYU Neuroscience Institute, New York University Grossman School of Medicine, New York, NY, USA.
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16
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Zhou GX, Liu WB, Dai LM, Zhu HL, Xiong YW, Li DX, Xu DX, Wang H. Environmental cadmium impairs blood-testis barrier via activating HRI-responsive mitochondrial stress in mice. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 810:152247. [PMID: 34896485 DOI: 10.1016/j.scitotenv.2021.152247] [Citation(s) in RCA: 21] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/14/2021] [Revised: 11/13/2021] [Accepted: 12/04/2021] [Indexed: 06/14/2023]
Abstract
Cadmium (Cd) is a well-known testicular toxicant. Blood-testis barrier (BTB), a vital part of testes, which has been reported to be damaged upon Cd exposure. However, the detailed mechanism about Cd-mediated disruption of BTB remains unclear. This study aims to investigate the role of Heme-Regulated Inhibitor (HRI)-responsive mitochondrial stress in Cd-mediated disruption of BTB. Male mice are intraperitoneally injected (i.p.) with melatonin (Mel, a cellular stress antagonist, 5.0 mg/kg) before Cd treatment (i.p., 2.0 mg/kg) for 8 h, and then treated with Cd for 0-48 h. Mouse Sertoli cells are pretreated with Mel (10 μM) for 1 h, and then treated with Cd (10 μM) for 0-24 h. We find that Cd damages the BTB and reduces the Occludin protein, a crucial BTB-related protein via activating p38/matrix metalloproteinase-2 (p38/MMP2) pathway and Integrated Stress Response (ISR). Further experiments reveal that the Heme-Regulated Inhibitor (HRI)-responsive mitochondrial stress is triggered in Cd-treated Sertoli cells. Most importantly, Cd-activated p38 signaling and ISR are regulated by HRI-responsive mitochondrial stress in Sertoli cells. Unexpectedly, we find that melatonin rescues the Cd-mediated disruption of BTB through blocking HRI-responsive mitochondrial stress in testes. Overall, these data indicate that environmental cadmium exposure impairs the BTB through activating HRI-responsive mitochondrial stress in Sertoli cells.
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Affiliation(s)
- Guo-Xiang Zhou
- Department of Toxicology, School of Public Health, Anhui Medical University, China; Key Laboratory of Environmental Toxicology of Anhui Higher Education Institutes, China
| | - Wei-Bo Liu
- Department of Toxicology, School of Public Health, Anhui Medical University, China; Key Laboratory of Environmental Toxicology of Anhui Higher Education Institutes, China
| | - Li-Min Dai
- Department of Toxicology, School of Public Health, Anhui Medical University, China; Key Laboratory of Environmental Toxicology of Anhui Higher Education Institutes, China
| | - Hua-Long Zhu
- Department of Toxicology, School of Public Health, Anhui Medical University, China; Key Laboratory of Environmental Toxicology of Anhui Higher Education Institutes, China
| | - Yong-Wei Xiong
- Department of Toxicology, School of Public Health, Anhui Medical University, China; Key Laboratory of Environmental Toxicology of Anhui Higher Education Institutes, China
| | - Dai-Xin Li
- Department of Toxicology, School of Public Health, Anhui Medical University, China; Key Laboratory of Environmental Toxicology of Anhui Higher Education Institutes, China
| | - De-Xiang Xu
- Department of Toxicology, School of Public Health, Anhui Medical University, China; Key Laboratory of Environmental Toxicology of Anhui Higher Education Institutes, China
| | - Hua Wang
- Department of Toxicology, School of Public Health, Anhui Medical University, China; Key Laboratory of Environmental Toxicology of Anhui Higher Education Institutes, China.
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17
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Shrestha P, Klann E. Spatiotemporally resolved protein synthesis as a molecular framework for memory consolidation. Trends Neurosci 2022; 45:297-311. [PMID: 35184897 PMCID: PMC8930706 DOI: 10.1016/j.tins.2022.01.004] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2021] [Revised: 01/21/2022] [Accepted: 01/25/2022] [Indexed: 01/25/2023]
Abstract
De novo protein synthesis is required for long-term memory consolidation. Dynamic regulation of protein synthesis occurs via a complex interplay of translation factors and modulators. Many components of the protein synthesis machinery have been targeted either pharmacologically or genetically to establish its requirement for memory. The combination of ligand/light-gating and genetic strategies, that is, chemogenetics and optogenetics, has begun to reveal the spatiotemporal resolution of protein synthesis in specific cell types during memory consolidation. This review summarizes current knowledge of the macroscopic and microscopic neural substrates for protein synthesis in memory consolidation. In addition, we highlight future directions for determining the localization and timing of de novo protein synthesis for memory consolidation with tools that permit unprecedented spatiotemporal precision.
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Affiliation(s)
- Prerana Shrestha
- Department of Neurobiology and Behavior, Stony Brook University, Stony Brook, NY 11794, USA.
| | - Eric Klann
- Center for Neural Science, New York University, New York, NY 10012, USA; NYU Neuroscience Institute, New York University Langone Medical Center, New York, NY 10016, USA.
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18
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Koppers M, Holt CE. Receptor-Ribosome Coupling: A Link Between Extrinsic Signals and mRNA Translation in Neuronal Compartments. Annu Rev Neurosci 2022; 45:41-61. [DOI: 10.1146/annurev-neuro-083021-110015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Axons receive extracellular signals that help to guide growth and synapse formation during development and to maintain neuronal function and survival during maturity. These signals relay information via cell surface receptors that can initiate local intracellular signaling at the site of binding, including local messenger RNA (mRNA) translation. Direct coupling of translational machinery to receptors provides an attractive way to activate this local mRNA translation and change the local proteome with high spatiotemporal resolution. Here, we first discuss the increasing evidence that different external stimuli trigger translation of specific subsets of mRNAs in axons via receptors and thus play a prominent role in various processes in both developing and mature neurons. We then discuss the receptor-mediated molecular mechanisms that regulate local mRNA translational with a focus on direct receptor-ribosome coupling. We advance the idea that receptor-ribosome coupling provides several advantages over other translational regulation mechanisms and is a common mechanism in cell communication. Expected final online publication date for the Annual Review of Neuroscience, Volume 45 is July 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.
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Affiliation(s)
- Max Koppers
- Department of Biology, Division of Cell Biology, Neurobiology and Biophysics, Utrecht University, Utrecht, The Netherlands
| | - Christine E. Holt
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, United Kingdom
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19
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Abstract
To form synaptic connections and store information, neurons continuously remodel their proteomes. The impressive length of dendrites and axons imposes logistical challenges to maintain synaptic proteins at locations remote from the transcription source (the nucleus). The discovery of thousands of messenger RNAs (mRNAs) near synapses suggested that neurons overcome distance and gain autonomy by producing proteins locally. It is not generally known, however, if, how, and when localized mRNAs are translated into protein. To investigate the translational landscape in neuronal subregions, we performed simultaneous RNA sequencing (RNA-seq) and ribosome sequencing (Ribo-seq) from microdissected rodent brain slices to identify and quantify the transcriptome and translatome in cell bodies (somata) as well as dendrites and axons (neuropil). Thousands of transcripts were differentially translated between somatic and synaptic regions, with many scaffold and signaling molecules displaying increased translation levels in the neuropil. Most translational changes between compartments could be accounted for by differences in RNA abundance. Pervasive translational regulation was observed in both somata and neuropil influenced by specific mRNA features (e.g., untranslated region [UTR] length, RNA-binding protein [RBP] motifs, and upstream open reading frames [uORFs]). For over 800 mRNAs, the dominant source of translation was the neuropil. We constructed a searchable and interactive database for exploring mRNA transcripts and their translation levels in the somata and neuropil [MPI Brain Research, The mRNA translation landscape in the synaptic neuropil. https://public.brain.mpg.de/dashapps/localseq/ Accessed 5 October 2021]. Overall, our findings emphasize the substantial contribution of local translation to maintaining synaptic protein levels and indicate that on-site translational control is an important mechanism to control synaptic strength.
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20
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Fusco CM, Desch K, Dörrbaum AR, Wang M, Staab A, Chan ICW, Vail E, Villeri V, Langer JD, Schuman EM. Neuronal ribosomes exhibit dynamic and context-dependent exchange of ribosomal proteins. Nat Commun 2021; 12:6127. [PMID: 34675203 PMCID: PMC8531293 DOI: 10.1038/s41467-021-26365-x] [Citation(s) in RCA: 45] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2021] [Accepted: 09/29/2021] [Indexed: 12/11/2022] Open
Abstract
Owing to their morphological complexity and dense network connections, neurons modify their proteomes locally, using mRNAs and ribosomes present in the neuropil (tissue enriched for dendrites and axons). Although ribosome biogenesis largely takes place in the nucleus and perinuclear region, neuronal ribosomal protein (RP) mRNAs have been frequently detected remotely, in dendrites and axons. Here, using imaging and ribosome profiling, we directly detected the RP mRNAs and their translation in the neuropil. Combining brief metabolic labeling with mass spectrometry, we found that a group of RPs rapidly associated with translating ribosomes in the cytoplasm and that this incorporation was independent of canonical ribosome biogenesis. Moreover, the incorporation probability of some RPs was regulated by location (neurites vs. cell bodies) and changes in the cellular environment (following oxidative stress). Our results suggest new mechanisms for the local activation, repair and/or specialization of the translational machinery within neuronal processes, potentially allowing neuronal synapses a rapid means to regulate local protein synthesis.
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Affiliation(s)
- Claudia M. Fusco
- grid.419505.c0000 0004 0491 3878Max Planck Institute for Brain Research, Frankfurt, Germany
| | - Kristina Desch
- grid.419505.c0000 0004 0491 3878Max Planck Institute for Brain Research, Frankfurt, Germany
| | - Aline R. Dörrbaum
- grid.419505.c0000 0004 0491 3878Max Planck Institute for Brain Research, Frankfurt, Germany ,Present Address: MOS, Center for Mass Spectrometry and Optical Spectroscopy, Mannheim, Germany
| | - Mantian Wang
- grid.419505.c0000 0004 0491 3878Max Planck Institute for Brain Research, Frankfurt, Germany ,grid.508836.0Present Address: Institute of Molecular and Clinical Ophthalmology, Basel, Switzerland
| | - Anja Staab
- grid.419505.c0000 0004 0491 3878Max Planck Institute for Brain Research, Frankfurt, Germany
| | - Ivy C. W. Chan
- grid.419505.c0000 0004 0491 3878Max Planck Institute for Brain Research, Frankfurt, Germany ,grid.424247.30000 0004 0438 0426Present Address: German Center for Neurodegenerative Diseases, Bonn, Germany
| | - Eleanor Vail
- grid.419505.c0000 0004 0491 3878Max Planck Institute for Brain Research, Frankfurt, Germany
| | - Veronica Villeri
- grid.419505.c0000 0004 0491 3878Max Planck Institute for Brain Research, Frankfurt, Germany ,grid.412041.20000 0001 2106 639XPresent Address: Department of Neuroscience, University of Bordeaux, Bordeaux, France
| | - Julian D. Langer
- grid.419505.c0000 0004 0491 3878Max Planck Institute for Brain Research, Frankfurt, Germany ,grid.419494.50000 0001 1018 9466Max Planck Institute for Biophysics, Frankfurt, Germany
| | - Erin M. Schuman
- grid.419505.c0000 0004 0491 3878Max Planck Institute for Brain Research, Frankfurt, Germany
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21
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Verma K, Verma M, Chaphalkar A, Chakraborty K. Recent advances in understanding the role of proteostasis. Fac Rev 2021; 10:72. [PMID: 34632458 PMCID: PMC8483240 DOI: 10.12703/r/10-72] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Maintenance of a functional proteome is achieved through the mechanism of proteostasis that involves precise coordination between molecular machineries assisting a protein from its conception to demise. Although each organelle within a cell has its own set of proteostasis machinery, inter-organellar communication and cell non-autonomous signaling bring forth the multidimensional nature of the proteostasis network. Exposure to extrinsic and intrinsic stressors can challenge the proteostasis network, leading to the accumulation of aberrant proteins or a decline in the proteostasis components, as seen during aging and in several diseases. Here, we summarize recent advances in understanding the role of proteostasis and its regulation in aging and disease, including monogenetic and infectious diseases. We highlight some of the emerging as well as unresolved questions in proteostasis that need to be addressed to overcome pathologies associated with damaged proteins and to promote healthy aging.
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Affiliation(s)
- Kanika Verma
- CSIR-Institute of Genomics and Integrative Biology, Mathura Road, Delhi, India
- Academy of Scientific and Innovative Research, CSIR-HRDC, Ghaziabad, Uttar Pradesh, India
| | - Monika Verma
- CSIR-Institute of Genomics and Integrative Biology, Mathura Road, Delhi, India
- Academy of Scientific and Innovative Research, CSIR-HRDC, Ghaziabad, Uttar Pradesh, India
| | - Aseem Chaphalkar
- CSIR-Institute of Genomics and Integrative Biology, Mathura Road, Delhi, India
- Academy of Scientific and Innovative Research, CSIR-HRDC, Ghaziabad, Uttar Pradesh, India
| | - Kausik Chakraborty
- CSIR-Institute of Genomics and Integrative Biology, Mathura Road, Delhi, India
- Academy of Scientific and Innovative Research, CSIR-HRDC, Ghaziabad, Uttar Pradesh, India
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22
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Giandomenico SL, Alvarez-Castelao B, Schuman EM. Proteostatic regulation in neuronal compartments. Trends Neurosci 2021; 45:41-52. [PMID: 34489114 DOI: 10.1016/j.tins.2021.08.002] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2021] [Revised: 07/16/2021] [Accepted: 08/05/2021] [Indexed: 12/16/2022]
Abstract
Neurons continuously adapt to external cues and challenges, including stimulation, plasticity-inducing signals and aging. These adaptations are critical for neuronal physiology and extended survival. Proteostasis is the process by which cells adjust their protein content to achieve the specific protein repertoire necessary for cellular function. Due to their complex morphology and polarized nature, neurons possess unique proteostatic requirements. Proteostatic control in axons and dendrites must be implemented through regulation of protein synthesis and degradation in a decentralized fashion, but at the same time, it requires integration, at least in part, in the soma. Here, we discuss current understanding of neuronal proteostasis, as well as open questions and future directions requiring further exploration.
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Affiliation(s)
| | - Beatriz Alvarez-Castelao
- Department of Biochemistry and Molecular Biology, Veterinary School, Complutense University of Madrid, Madrid, Spain
| | - Erin M Schuman
- Max Planck Institute for Brain Research, Frankfurt am Main, Germany.
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23
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English AM, Green KM, Moon SL. A (dis)integrated stress response: Genetic diseases of eIF2α regulators. WILEY INTERDISCIPLINARY REVIEWS-RNA 2021; 13:e1689. [PMID: 34463036 DOI: 10.1002/wrna.1689] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/15/2021] [Revised: 08/03/2021] [Accepted: 08/04/2021] [Indexed: 01/28/2023]
Abstract
The integrated stress response (ISR) is a conserved mechanism by which eukaryotic cells remodel gene expression to adapt to intrinsic and extrinsic stressors rapidly and reversibly. The ISR is initiated when stress-activated protein kinases phosphorylate the major translation initiation factor eukaryotic translation initiation factor 2ɑ (eIF2ɑ), which globally suppresses translation initiation activity and permits the selective translation of stress-induced genes including important transcription factors such as activating transcription factor 4 (ATF4). Translationally repressed messenger RNAs (mRNAs) and noncoding RNAs assemble into cytoplasmic RNA-protein granules and polyadenylated RNAs are concomitantly stabilized. Thus, regulated changes in mRNA translation, stability, and localization to RNA-protein granules contribute to the reprogramming of gene expression that defines the ISR. We discuss fundamental mechanisms of RNA regulation during the ISR and provide an overview of a growing class of genetic disorders associated with mutant alleles of key translation factors in the ISR pathway. This article is categorized under: RNA Interactions with Proteins and Other Molecules > Protein-RNA Interactions: Functional Implications RNA in Disease and Development > RNA in Disease Translation > Translation Regulation RNA in Disease and Development > RNA in Development.
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Affiliation(s)
- Alyssa M English
- Department of Human Genetics, Center for RNA Biomedicine, University of Michigan, Ann Arbor, Michigan, USA
| | - Katelyn M Green
- Department of Chemistry, Department of Human Genetics, Center for RNA Biomedicine, University of Michigan, Ann Arbor, Michigan, USA
| | - Stephanie L Moon
- Department of Human Genetics, Center for RNA Biomedicine, University of Michigan, Ann Arbor, Michigan, USA
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24
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Perez JD, Fusco CM, Schuman EM. A Functional Dissection of the mRNA and Locally Synthesized Protein Population in Neuronal Dendrites and Axons. Annu Rev Genet 2021; 55:183-207. [PMID: 34460296 DOI: 10.1146/annurev-genet-030321-054851] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Neurons are characterized by a complex morphology that enables the generation of subcellular compartments with unique biochemical and biophysical properties, such as dendrites, axons, and synapses. To sustain these different compartments and carry a wide array of elaborate operations, neurons express a diverse repertoire of gene products. Extensive regulation at both the messenger RNA (mRNA) and protein levels allows for the differentiation of subcellular compartments as well as numerous forms of plasticity in response to variable stimuli. Among the multiple mechanisms that control cellular functions, mRNA translation is manipulated by neurons to regulate where and when a protein emerges. Interestingly, transcriptomic and translatomic profiles of both dendrites and axons have revealed that the mRNA population only partially predicts the local protein population and that this relation significantly varies between different gene groups. Here, we describe the space that local translation occupies within the large molecular and regulatory complexity of neurons, in contrast to other modes of regulation. We then discuss the specialized organization of mRNAs within different neuronal compartments, as revealed by profiles of the local transcriptome. Finally, we discuss the features and functional implications of both locally correlated-and anticorrelated-mRNA-protein relations both under baseline conditions and during synaptic plasticity. Expected final online publication date for the Annual Review of Genetics, Volume 55 is November 2021. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.
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Affiliation(s)
- Julio D Perez
- Max Planck Institute for Brain Research, 60438 Frankfurt, Germany;
| | - Claudia M Fusco
- Max Planck Institute for Brain Research, 60438 Frankfurt, Germany;
| | - Erin M Schuman
- Max Planck Institute for Brain Research, 60438 Frankfurt, Germany;
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25
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Koncha RR, Ramachandran G, Sepuri NBV, Ramaiah KVA. CCCP-induced mitochondrial dysfunction - characterization and analysis of integrated stress response to cellular signaling and homeostasis. FEBS J 2021; 288:5737-5754. [PMID: 33837631 DOI: 10.1111/febs.15868] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2020] [Revised: 02/26/2021] [Accepted: 04/07/2021] [Indexed: 12/11/2022]
Abstract
Mitochondrial dysfunction mediated by CCCP (carbonyl cyanide m-chlorophenyl hydrazone), an inhibitor of mitochondrial oxidative phosphorylation, evokes the integrated stress response (ISR), which is analyzed here by eIF2α phosphorylation and expression profiles of ATF4 and CHOP proteins. Our findings suggest that the CCCP-induced ISR pathway is mediated by activation of HRI kinase, but not by GCN2, PERK, or PKR. Also, CCCP activates AMPK, a cellular energy sensor, and AKT, a regulator implicated in cell survival, and suppresses phosphorylation of mTORC1 substrates eIF4E-BP1 and S6K. CCCP also downregulates translation and promotes autophagy, leading to noncaspase-mediated cell death in HepG2 cells. All these events are neutralized by NAC, an anti-ROS, suggesting that CCCP-induced mitochondrial dysfunction promotes oxidative stress. ISRIB, an inhibitor of the ISR pathway, mitigates CCCP-induced expression of ATF4 and CHOP, activation of AKT, and autophagy, similar to NAC. However, it fails to reverse CCCP-induced AMPK activation, suggesting that CCCP-induced autophagy is dependent on ISR and independent of AMPK activation. ISRIB restores partly, inhibition in eIF4E-BP1 phosphorylation, promotes eIF2α phosphorylation, albeit slowly, and mitigates suppression of translation accordingly, in CCCP-treated cells. These findings are consistent with the idea that CCCP-induced oxidative stress leading to eIF2α phosphorylation and ATF4 expression, which is known to stimulate genes involved in autophagy, play a pro-survival role together with AKT activation and regulate mTOR-mediated eIF4E-BP1 phosphorylation.
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Affiliation(s)
| | - Gayatri Ramachandran
- Department of Biochemistry, School of Life Sciences, University of Hyderabad, India
| | - Naresh Babu V Sepuri
- Department of Biochemistry, School of Life Sciences, University of Hyderabad, India
| | - Kolluru V A Ramaiah
- Department of Biochemistry, School of Life Sciences, University of Hyderabad, India
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26
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Perez JD, Dieck ST, Alvarez-Castelao B, Tushev G, Chan IC, Schuman EM. Subcellular sequencing of single neurons reveals the dendritic transcriptome of GABAergic interneurons. eLife 2021; 10:63092. [PMID: 33404500 PMCID: PMC7819707 DOI: 10.7554/elife.63092] [Citation(s) in RCA: 39] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2020] [Accepted: 01/05/2021] [Indexed: 12/23/2022] Open
Abstract
Although mRNAs are localized in the processes of excitatory neurons, it is still unclear whether interneurons also localize a large population of mRNAs. In addition, the variability in the localized mRNA population within and between cell types is unknown. Here we describe the unbiased transcriptomic characterization of the subcellular compartments of hundreds of single neurons. We separately profiled the dendritic and somatic transcriptomes of individual rat hippocampal neurons and investigated mRNA abundances in the soma and dendrites of single glutamatergic and GABAergic neurons. We found that, like their excitatory counterparts, interneurons contain a rich repertoire of ~4000 mRNAs. We observed more cell type-specific features among somatic transcriptomes than their associated dendritic transcriptomes. Finally, using celltype-specific metabolic labeling of isolated neurites, we demonstrated that the processes of glutamatergic and, notably, GABAergic neurons were capable of local translation, suggesting mRNA localization and local translation are general properties of neurons.
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Affiliation(s)
- Julio D Perez
- Max Planck Institute for Brain Research, Frankfurt am Main, Germany
| | | | - Beatriz Alvarez-Castelao
- Department of Biochemistry and Molecular Biology, Veterinary School, Complutense University of Madrid, Madrid, Spain
| | - Georgi Tushev
- Max Planck Institute for Brain Research, Frankfurt am Main, Germany
| | - Ivy Cw Chan
- Department of Behavior and Brain Organization, Center of Advanced European Studies and Research, Bonn, Germany
| | - Erin M Schuman
- Max Planck Institute for Brain Research, Frankfurt am Main, Germany
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27
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Mukherjee T, Ramaglia V, Abdel-Nour M, Bianchi AA, Tsalikis J, Chau HN, Kalia SK, Kalia LV, Chen JJ, Arnoult D, Gommerman JL, Philpott DJ, Girardin SE. The eIF2α kinase HRI triggers the autophagic clearance of cytosolic protein aggregates. J Biol Chem 2021; 296:100050. [PMID: 33168630 PMCID: PMC7948985 DOI: 10.1074/jbc.ra120.014415] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2020] [Revised: 10/27/2020] [Accepted: 11/09/2020] [Indexed: 12/21/2022] Open
Abstract
Large cytosolic protein aggregates are removed by two main cellular processes, autophagy and the ubiquitin-proteasome system, and defective clearance of these protein aggregates results in proteotoxicity and cell death. Recently, we found that the eIF2α kinase heme-regulated inhibitory (HRI) induced a cytosolic unfolded protein response to prevent aggregation of innate immune signalosomes, but whether HRI acts as a general sensor of proteotoxicity in the cytosol remains unclear. Here we show that HRI controls autophagy to clear cytosolic protein aggregates when the ubiquitin-proteasome system is inhibited. We further report that silencing the expression of HRI resulted in decreased levels of BAG3 and HSPB8, two proteins involved in chaperone-assisted selective autophagy, suggesting that HRI may control proteostasis in the cytosol at least in part through chaperone-assisted selective autophagy. Moreover, knocking down the expression of HRI resulted in cytotoxic accumulation of overexpressed α-synuclein, a protein known to aggregate in Parkinson's disease, dementia with Lewy bodies, and multiple system atrophy. In agreement with these data, protein aggregate accumulation and microglia activation were observed in the spinal cord white matter of 7-month-old Hri-/- mice as compared with Hri+/+ littermates. Moreover, aged Hri-/- mice showed accumulation of misfolded α-synuclein in the lateral collateral pathway, a region of the sacral spinal cord horn that receives visceral sensory afferents from the bladder and distal colon, a pathological feature common to α-synucleinopathies in humans. Together, these results suggest that HRI contributes to a general cytosolic unfolded protein response that could be leveraged to bolster the clearance of cytotoxic protein aggregates.
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Affiliation(s)
- Tapas Mukherjee
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, Canada; Department of Immunology, University of Toronto, Toronto, Ontario, Canada
| | - Valeria Ramaglia
- Department of Immunology, University of Toronto, Toronto, Ontario, Canada
| | - Mena Abdel-Nour
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, Canada
| | - Athanasia A Bianchi
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, Canada
| | - Jessica Tsalikis
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, Canada
| | - Hien N Chau
- Krembil Research Institute, Toronto Western Hospital, University Health Network, Toronto, Canada
| | - Suneil K Kalia
- Krembil Research Institute, Toronto Western Hospital, University Health Network, Toronto, Canada
| | - Lorraine V Kalia
- Krembil Research Institute, Toronto Western Hospital, University Health Network, Toronto, Canada
| | - Jane-Jane Chen
- Institute of Medical Engineering & Science, MIT, Cambridge, Massachusetts, USA
| | - Damien Arnoult
- INSERM U1197, Hôpital Paul Brousse, Bâtiment Lavoisier, Villejuif Cedex, France; Université Paris-Saclay, Paris, France
| | | | - Dana J Philpott
- Department of Immunology, University of Toronto, Toronto, Ontario, Canada
| | - Stephen E Girardin
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, Canada; Department of Immunology, University of Toronto, Toronto, Ontario, Canada.
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28
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Ross AB, Langer JD, Jovanovic M. Proteome Turnover in the Spotlight: Approaches, Applications, and Perspectives. Mol Cell Proteomics 2020; 20:100016. [PMID: 33556866 PMCID: PMC7950106 DOI: 10.1074/mcp.r120.002190] [Citation(s) in RCA: 56] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2020] [Revised: 11/25/2020] [Accepted: 11/30/2020] [Indexed: 01/17/2023] Open
Abstract
In all cells, proteins are continuously synthesized and degraded to maintain protein homeostasis and modify gene expression levels in response to stimuli. Collectively, the processes of protein synthesis and degradation are referred to as protein turnover. At a steady state, protein turnover is constant to maintain protein homeostasis, but in dynamic responses, proteins change their rates of synthesis and degradation to adjust their proteomes to internal or external stimuli. Thus, probing the kinetics and dynamics of protein turnover lends insight into how cells regulate essential processes such as growth, differentiation, and stress response. Here, we outline historical and current approaches to measuring the kinetics of protein turnover on a proteome-wide scale in both steady-state and dynamic systems, with an emphasis on metabolic tracing using stable isotope-labeled amino acids. We highlight important considerations for designing proteome turnover experiments, key biological findings regarding the conserved principles of proteome turnover regulation, and future perspectives for both technological and biological investigation.
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Affiliation(s)
- Alison Barbara Ross
- Department of Biological Sciences, Columbia University, New York, New York, USA
| | - Julian David Langer
- Proteomics, Max Planck Institute of Biophysics, Frankfurt am Main, Germany; Proteomics, Max Planck Institute for Brain Research, Frankfurt am Main, Germany.
| | - Marko Jovanovic
- Department of Biological Sciences, Columbia University, New York, New York, USA.
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29
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Girardin SE, Cuziol C, Philpott DJ, Arnoult D. The eIF2α kinase HRI in innate immunity, proteostasis, and mitochondrial stress. FEBS J 2020; 288:3094-3107. [DOI: 10.1111/febs.15553] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2020] [Revised: 08/09/2020] [Accepted: 09/01/2020] [Indexed: 12/13/2022]
Affiliation(s)
- Stephen E. Girardin
- Department of Laboratory Medicine and Pathobiology University of Toronto ON Canada
| | - Camille Cuziol
- INSERM UMR_S 1197 Hôpital Paul Brousse Villejuif France
- Université Paris‐Saclay France
| | | | - Damien Arnoult
- INSERM UMR_S 1197 Hôpital Paul Brousse Villejuif France
- Université Paris‐Saclay France
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