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Wu S, Lin W. The physiological role of the unfolded protein response in the nervous system. Neural Regen Res 2024; 19:2411-2420. [PMID: 38526277 PMCID: PMC11090440 DOI: 10.4103/1673-5374.393105] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2023] [Accepted: 12/12/2023] [Indexed: 03/26/2024] Open
Abstract
The unfolded protein response (UPR) is a cellular stress response pathway activated when the endoplasmic reticulum, a crucial organelle for protein folding and modification, encounters an accumulation of unfolded or misfolded proteins. The UPR aims to restore endoplasmic reticulum homeostasis by enhancing protein folding capacity, reducing protein biosynthesis, and promoting protein degradation. It also plays a pivotal role in coordinating signaling cascades to determine cell fate and function in response to endoplasmic reticulum stress. Recent research has highlighted the significance of the UPR not only in maintaining endoplasmic reticulum homeostasis but also in influencing various physiological processes in the nervous system. Here, we provide an overview of recent findings that underscore the UPR's involvement in preserving the function and viability of neuronal and myelinating cells under physiological conditions, and highlight the critical role of the UPR in brain development, memory storage, retinal cone development, myelination, and maintenance of myelin thickness.
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Affiliation(s)
- Shuangchan Wu
- Department of Neuroscience, University of Minnesota, Minneapolis, MN, USA
- Institute for Translational Neuroscience, University of Minnesota, Minneapolis, MN, USA
| | - Wensheng Lin
- Department of Neuroscience, University of Minnesota, Minneapolis, MN, USA
- Institute for Translational Neuroscience, University of Minnesota, Minneapolis, MN, USA
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2
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Lockshin ER, Calakos N. The integrated stress response in brain diseases: A double-edged sword for proteostasis and synapses. Curr Opin Neurobiol 2024; 87:102886. [PMID: 38901329 DOI: 10.1016/j.conb.2024.102886] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2024] [Revised: 05/22/2024] [Accepted: 05/24/2024] [Indexed: 06/22/2024]
Abstract
The integrated stress response (ISR) is a highly conserved biochemical pathway that regulates protein synthesis. The ISR is activated in response to diverse stressors to restore cellular homeostasis. As such, the ISR is implicated in a wide range of diseases, including brain disorders. However, in the brain, the ISR also has potent influence on processes beyond proteostasis, namely synaptic plasticity, learning and memory. Thus, in the setting of brain diseases, ISR activity may have dual effects on proteostasis and synaptic function. In this review, we consider the ISR's contribution to brain disorders through the lens of its potential effects on synaptic plasticity. From these examples, we illustrate that at times ISR activity may be a "double-edged sword". We also highlight its potential as a therapeutic target to improve circuit function in brain diseases independent of its role in disease pathogenesis.
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Affiliation(s)
- Elana R Lockshin
- Department of Neurobiology, Duke University Medical Center, Durham, NC 27710, USA; Aligning Science Across Parkinson's (ASAP) Collaborative Research Network, Chevy Chase, MD 20815, USA
| | - Nicole Calakos
- Department of Neurobiology, Duke University Medical Center, Durham, NC 27710, USA; Aligning Science Across Parkinson's (ASAP) Collaborative Research Network, Chevy Chase, MD 20815, USA; Department of Neurology, Duke University Medical Center, Durham, NC 27710, USA; Department of Cell Biology, Duke University Medical Center, Durham, NC 27710, USA.
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3
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Fonda BD, Kato M, Li Y, Murray DT. Cryo-EM and Solid State NMR Together Provide a More Comprehensive Structural Investigation of Protein Fibrils. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.05.30.596698. [PMID: 38853912 PMCID: PMC11160737 DOI: 10.1101/2024.05.30.596698] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2024]
Abstract
The Tropomyosin 1 isoform I/C C-terminal domain (Tm1-LC) fibril structure is studied jointly with cryogenic electron microscopy (cryo-EM) and solid state nuclear magnetic resonance (NMR). This study demonstrates the complementary nature of these two structural biology techniques. Chemical shift assignments from solid state NMR are used to determine the secondary structure at the level of individual amino acids, which is faithfully seen in cryo-EM reconstructions. Additionally, solid state NMR demonstrates that the region not observed in the reconstructed cryo-EM density is primarily in a highly mobile random coil conformation rather than adopting multiple rigid conformations. Overall, this study illustrates the benefit of investigations combining cryo-EM and solid state NMR to investigate protein fibril structure.
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Affiliation(s)
- Blake D. Fonda
- Department of Chemistry, University of California, Davis, California, 95616, United States of America
| | - Masato Kato
- Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas, Texas, 75390, United States of America
| | - Yang Li
- Department of Biophysics, University of Texas Southwestern Medical Center, Dallas, Texas, 75390, United States of America
| | - Dylan T. Murray
- Department of Molecular and Cell Biology, University of Connecticut, Storrs, Connecticut, 06269, United States of America
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4
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Henis M, Rücker T, Scharrenberg R, Richter M, Baltussen L, Hong S, Meka DP, Schwanke B, Neelagandan N, Daaboul D, Murtaza N, Krisp C, Harder S, Schlüter H, Kneussel M, Hermans-Borgmeyer I, de Wit J, Singh KK, Duncan KE, de Anda FC. The autism susceptibility kinase, TAOK2, phosphorylates eEF2 and modulates translation. SCIENCE ADVANCES 2024; 10:eadf7001. [PMID: 38608030 PMCID: PMC11014455 DOI: 10.1126/sciadv.adf7001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/08/2022] [Accepted: 03/12/2024] [Indexed: 04/14/2024]
Abstract
Genes implicated in translation control have been associated with autism spectrum disorders (ASDs). However, some important genetic causes of autism, including the 16p11.2 microdeletion, bear no obvious connection to translation. Here, we use proteomics, genetics, and translation assays in cultured cells and mouse brain to reveal altered translation mediated by loss of the kinase TAOK2 in 16p11.2 deletion models. We show that TAOK2 associates with the translational machinery and functions as a translational brake by phosphorylating eukaryotic elongation factor 2 (eEF2). Previously, all signal-mediated regulation of translation elongation via eEF2 phosphorylation was believed to be mediated by a single kinase, eEF2K. However, we show that TAOK2 can directly phosphorylate eEF2 on the same regulatory site, but functions independently of eEF2K signaling. Collectively, our results reveal an eEF2K-independent signaling pathway for control of translation elongation and suggest altered translation as a molecular component in the etiology of some forms of ASD.
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Affiliation(s)
- Melad Henis
- Center for Molecular Neurobiology, University Medical Center Hamburg-Eppendorf, 20251 Hamburg, Germany
- Department of Anatomy and Embryology, Faculty of Veterinary Medicine, New Valley University, 72511 El-Kharga, Egypt
| | - Tabitha Rücker
- Center for Molecular Neurobiology, University Medical Center Hamburg-Eppendorf, 20251 Hamburg, Germany
| | - Robin Scharrenberg
- Center for Molecular Neurobiology, University Medical Center Hamburg-Eppendorf, 20251 Hamburg, Germany
| | - Melanie Richter
- Center for Molecular Neurobiology, University Medical Center Hamburg-Eppendorf, 20251 Hamburg, Germany
| | - Lucas Baltussen
- VIB Center for Brain & Disease Research, Herestraat 49, 3000 Leuven, Belgium
- KU Leuven Department of Neurosciences, Leuven Brain Institute, Herestraat 49, 3000 Leuven, Belgium
| | - Shuai Hong
- Center for Molecular Neurobiology, University Medical Center Hamburg-Eppendorf, 20251 Hamburg, Germany
| | - Durga Praveen Meka
- Center for Molecular Neurobiology, University Medical Center Hamburg-Eppendorf, 20251 Hamburg, Germany
| | - Birgit Schwanke
- Center for Molecular Neurobiology, University Medical Center Hamburg-Eppendorf, 20251 Hamburg, Germany
| | - Nagammal Neelagandan
- Neuronal Translational Control Group, Center for Molecular Neurobiology (ZMNH), University Medical Center Hamburg-Eppendorf (UKE), Falkenried 94, 20251 Hamburg, Germany
- Institute of Bioengineering (IBI), École Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| | - Danie Daaboul
- VIB Center for Brain & Disease Research, Herestraat 49, 3000 Leuven, Belgium
- KU Leuven Department of Neurosciences, Leuven Brain Institute, Herestraat 49, 3000 Leuven, Belgium
| | - Nadeem Murtaza
- Krembil Research Institute, Donald K. Johnson Eye Institute, University Health Network, 60 Leonard Ave, Toronto, Ontario M5T 0S8, Canada
- Department of Biochemistry and Biomedical Sciences, Faculty of Health Sciences, McMaster University, Hamilton, Ontario L8S 4A9, Canada
| | - Christoph Krisp
- Institute for Clinical Chemistry and Laboratory Medicine, Mass Spectrometric Proteomics Group, Campus Forschung, University Medical Center Hamburg-Eppendorf (UKE), 20246 Hamburg, Germany
| | - Sönke Harder
- Institute for Clinical Chemistry and Laboratory Medicine, Mass Spectrometric Proteomics Group, Campus Forschung, University Medical Center Hamburg-Eppendorf (UKE), 20246 Hamburg, Germany
| | - Hartmut Schlüter
- Institute for Clinical Chemistry and Laboratory Medicine, Mass Spectrometric Proteomics Group, Campus Forschung, University Medical Center Hamburg-Eppendorf (UKE), 20246 Hamburg, Germany
| | - Matthias Kneussel
- Institute of Neurogenetics, Center for Molecular Neurobiology, University Medical Center Hamburg-Eppendorf (UKE), 20251 Hamburg, Germany
| | - Irm Hermans-Borgmeyer
- Transgenic Service Group, Center for Molecular Neurobiology (ZMNH), University Medical Center Hamburg-Eppendorf (UKE), Falkenried 94, 20251 Hamburg, Germany
| | - Joris de Wit
- VIB Center for Brain & Disease Research, Herestraat 49, 3000 Leuven, Belgium
- KU Leuven Department of Neurosciences, Leuven Brain Institute, Herestraat 49, 3000 Leuven, Belgium
| | - Karun K. Singh
- Krembil Research Institute, Donald K. Johnson Eye Institute, University Health Network, 60 Leonard Ave, Toronto, Ontario M5T 0S8, Canada
- Faculty of Medicine, University of Toronto, Medical Sciences Building, 1 King's College Cir, Toronto, Ontario M5S 1 A8, Canada
| | - Kent E. Duncan
- Neuronal Translational Control Group, Center for Molecular Neurobiology (ZMNH), University Medical Center Hamburg-Eppendorf (UKE), Falkenried 94, 20251 Hamburg, Germany
- Evotec SE, Manfred Eigen Campus, Essener Bogen 7, 22419 Hamburg, Germany
| | - Froylan Calderón de Anda
- Center for Molecular Neurobiology, University Medical Center Hamburg-Eppendorf, 20251 Hamburg, Germany
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Calakos N, Caffall ZF. The integrated stress response pathway and neuromodulator signaling in the brain: lessons learned from dystonia. J Clin Invest 2024; 134:e177833. [PMID: 38557486 PMCID: PMC10977992 DOI: 10.1172/jci177833] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/04/2024] Open
Abstract
The integrated stress response (ISR) is a highly conserved biochemical pathway involved in maintaining proteostasis and cell health in the face of diverse stressors. In this Review, we discuss a relatively noncanonical role for the ISR in neuromodulatory neurons and its implications for synaptic plasticity, learning, and memory. Beyond its roles in stress response, the ISR has been extensively studied in the brain, where it potently influences learning and memory, and in the process of synaptic plasticity, which is a substrate for adaptive behavior. Recent findings demonstrate that some neuromodulatory neuron types engage the ISR in an "always-on" mode, rather than the more canonical "on-demand" response to transient perturbations. Atypical demand for the ISR in neuromodulatory neurons introduces an additional mechanism to consider when investigating ISR effects on synaptic plasticity, learning, and memory. This basic science discovery emerged from a consideration of how the ISR might be contributing to human disease. To highlight how, in scientific discovery, the route from starting point to outcomes can often be circuitous and full of surprise, we begin by describing our group's initial introduction to the ISR, which arose from a desire to understand causes for a rare movement disorder, dystonia. Ultimately, the unexpected connection led to a deeper understanding of its fundamental role in the biology of neuromodulatory neurons, learning, and memory.
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Affiliation(s)
- Nicole Calakos
- Department of Neurology
- Department of Neurobiology, and
- Department of Cell Biology, Duke University Medical Center, Durham, North Carolina, USA
- Aligning Science Across Parkinson’s (ASAP) Collaborative Research Network, Chevy Chase, Maryland, USA
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6
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Grosshans D, Thomas R, Zhang D, Cronkite C, Thomas R, Singh S, Bronk L, Morales R, Duman J. Subcellular functions of tau mediates repair response and synaptic homeostasis in injury. RESEARCH SQUARE 2024:rs.3.rs-3897741. [PMID: 38464175 PMCID: PMC10925419 DOI: 10.21203/rs.3.rs-3897741/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/12/2024]
Abstract
Injury responses in terminally differentiated cells such as neurons is tightly regulated by pathways aiding homeostatic maintenance. Cancer patients subjected to neuronal injury in brain radiation experience cognitive declines similar to those seen in primary neurodegenerative diseases. Numerous studies have investigated the effect of radiation in proliferating cells of the brain, yet the impact in differentiated, post-mitotic neurons, especially the structural and functional alterations remain largely elusive. We identified that microtubule-associated tau is a critical player in neuronal injury response via compartmentalized functions in both repair-centric and synaptic regulatory pathways. Ionizing radiation-induced injury acutely induces increase in phosphorylated tau in the nucleus and directly interacts with histone 2AX (H2AX), a DNA damage repair (DDR) marker. Loss of tau significantly reduced H2AX after irradiation, indicating that tau may play an important role in neuronal DDR response. We also observed that loss of tau increases eukaryotic elongation factor levels after irradiation, the latter being a positive regulator of protein translation. This cascades into a significant increase in synaptic proteins, resulting in disrupted homeostasis. Consequently, novel object recognition test showed decrease in learning and memory in tau-knockout mice after irradiation, and electroencephalographic activity showed increase in delta and theta band oscillations, often seen in dementia patients. Our findings demonstrate tau's previously undefined, multifunctional role in acute responses to injury, ranging from DDR response in the nucleus to synaptic function within a neuron. Such knowledge is vital to develop therapeutic strategies targeting neuronal injury in cognitive decline for at risk and vulnerable populations.
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Castillo Díaz F, Mottarlini F, Targa G, Rizzi B, Fumagalli F, Caffino L. Recency memory is altered in cocaine-withdrawn adolescent rats: Implication of cortical mTOR signaling. Prog Neuropsychopharmacol Biol Psychiatry 2023; 127:110822. [PMID: 37442333 DOI: 10.1016/j.pnpbp.2023.110822] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/12/2022] [Revised: 06/28/2023] [Accepted: 07/06/2023] [Indexed: 07/15/2023]
Abstract
In humans, cocaine abuse during adolescence poses a significant risk for developing cognitive deficits later in life. Among the regions responsible for cognitive processes, the medial prefrontal cortex (mPFC) modulates temporal order information via mechanisms involving the mammalian-target of rapamycin (mTOR)-mediated pathway and protein synthesis regulation. Accordingly, our goal was to study the effect of repeated cocaine exposure during both adolescence and adulthood on temporal memory by studying the mTOR pathway in the mPFC. Adolescent or adult rats underwent repeated cocaine injections for 15 days and, after two weeks of withdrawal, engaged in the temporal order object recognition (TOOR) test. We found that repeated cocaine exposure during adolescence impaired TOOR performance, while control or adult-treated animals showed no impairments. Moreover, activation of the mTOR-S6-eEF2 pathway following the TOOR test was diminished only in the adolescent cocaine-treated group. Notably, inhibition of the mTOR-mediated pathway by rapamycin injection impaired TOOR performance in naïve adolescent and adult animals, revealing this pathway to be a critical component in regulating recency memory. Our data indicate that withdrawal from cocaine exposure impairs recency memory via the dysregulation of protein translation mechanisms, but only when cocaine is administered during adolescence.
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Affiliation(s)
- Fernando Castillo Díaz
- Department of Pharmacological and Biomolecular Sciences 'Rodolfo Paoletti', Università degli Studi di Milano, Milan 20133, Italy; Department of Behavioural and Molecular Neurobiology, University of Regensburg, Regensburg 93053, Germany
| | - Francesca Mottarlini
- Department of Pharmacological and Biomolecular Sciences 'Rodolfo Paoletti', Università degli Studi di Milano, Milan 20133, Italy
| | - Giorgia Targa
- Department of Pharmacological and Biomolecular Sciences 'Rodolfo Paoletti', Università degli Studi di Milano, Milan 20133, Italy
| | - Beatrice Rizzi
- Department of Pharmacological and Biomolecular Sciences 'Rodolfo Paoletti', Università degli Studi di Milano, Milan 20133, Italy; Center for Neuroscience, University of Camerino, Camerino 62032, Italy
| | - Fabio Fumagalli
- Department of Pharmacological and Biomolecular Sciences 'Rodolfo Paoletti', Università degli Studi di Milano, Milan 20133, Italy.
| | - Lucia Caffino
- Department of Pharmacological and Biomolecular Sciences 'Rodolfo Paoletti', Università degli Studi di Milano, Milan 20133, Italy
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Sharma V, Oliveira MM, Sood R, Khlaifia A, Lou D, Hooshmandi M, Hung TY, Mahmood N, Reeves M, Ho-Tieng D, Cohen N, Cheng PC, Rahim MMA, Prager-Khoutorsky M, Kaufman RJ, Rosenblum K, Lacaille JC, Khoutorsky A, Klann E, Sonenberg N. mRNA translation in astrocytes controls hippocampal long-term synaptic plasticity and memory. Proc Natl Acad Sci U S A 2023; 120:e2308671120. [PMID: 38015848 PMCID: PMC10710058 DOI: 10.1073/pnas.2308671120] [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: 05/26/2023] [Accepted: 10/23/2023] [Indexed: 11/30/2023] Open
Abstract
Activation of neuronal protein synthesis upon learning is critical for the formation of long-term memory. Here, we report that learning in the contextual fear conditioning paradigm engenders a decrease in eIF2α (eukaryotic translation initiation factor 2) phosphorylation in astrocytes in the hippocampal CA1 region, which promotes protein synthesis. Genetic reduction of eIF2α phosphorylation in hippocampal astrocytes enhanced contextual and spatial memory and lowered the threshold for the induction of long-lasting plasticity by modulating synaptic transmission. Thus, learning-induced dephosphorylation of eIF2α in astrocytes bolsters hippocampal synaptic plasticity and consolidation of long-term memories.
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Affiliation(s)
- Vijendra Sharma
- Department of Biomedical Sciences, University of Windsor, Windsor, ONN9B3P4, Canada
| | | | - Rapita Sood
- Department of Biochemistry, McGill University, Montréal, QCH3G1Y6, Canada
- Rosalind and Morris Goodman Cancer Institute, McGill University, Montréal, QCH3A1A3, Canada
| | - Abdessattar Khlaifia
- Department of Neurosciences, Center for Interdisciplinary Research on Brain and Learning, Research Group on Neural Signaling and Circuitry, University of Montréal, Montréal, QCH3T1J4, Canada
- Department of Psychology, University of Toronto Scarborough, Toronto, ONM1C1A4, Canada
| | - Danning Lou
- Department of Biochemistry, McGill University, Montréal, QCH3G1Y6, Canada
- Rosalind and Morris Goodman Cancer Institute, McGill University, Montréal, QCH3A1A3, Canada
| | - Mehdi Hooshmandi
- Department of Anesthesia and Faculty of Dental Medicine and Oral Health Sciences, McGill University, Montréal, QCH4A3J1, Canada
| | - Tzu-Yu Hung
- Department of Biochemistry, McGill University, Montréal, QCH3G1Y6, Canada
- Rosalind and Morris Goodman Cancer Institute, McGill University, Montréal, QCH3A1A3, Canada
| | - Niaz Mahmood
- Department of Biochemistry, McGill University, Montréal, QCH3G1Y6, Canada
- Rosalind and Morris Goodman Cancer Institute, McGill University, Montréal, QCH3A1A3, Canada
| | - Maya Reeves
- Department of Biomedical Sciences, University of Windsor, Windsor, ONN9B3P4, Canada
| | - David Ho-Tieng
- Department of Anesthesia and Faculty of Dental Medicine and Oral Health Sciences, McGill University, Montréal, QCH4A3J1, Canada
| | - Noah Cohen
- Department of Biochemistry, McGill University, Montréal, QCH3G1Y6, Canada
- Rosalind and Morris Goodman Cancer Institute, McGill University, Montréal, QCH3A1A3, Canada
| | - Po-chieh Cheng
- Department of Biochemistry, McGill University, Montréal, QCH3G1Y6, Canada
- Rosalind and Morris Goodman Cancer Institute, McGill University, Montréal, QCH3A1A3, Canada
| | - Mir Munir A. Rahim
- Department of Biomedical Sciences, University of Windsor, Windsor, ONN9B3P4, Canada
| | | | - Randal J. Kaufman
- Degenerative Diseases Program Center for Genetic Disease and Aging Research Sanford-Burnham-Prebys Medical Discovery Institute, La Jolla, CA92037
| | - Kobi Rosenblum
- Sagol Department of Neurobiology, University of Haifa, Haifa3498838, Israel
- Center for Gene Manipulation in the Brain, University of Haifa, Haifa3498838, Israel
| | - Jean-Claude Lacaille
- Department of Neurosciences, Center for Interdisciplinary Research on Brain and Learning, Research Group on Neural Signaling and Circuitry, University of Montréal, Montréal, QCH3T1J4, Canada
| | - Arkady Khoutorsky
- Department of Anesthesia and Faculty of Dental Medicine and Oral Health Sciences, McGill University, Montréal, QCH4A3J1, Canada
- Alan Edwards Centre for Research on Pain, McGill University, Montréal, QCH3A2B4, Canada
| | - Eric Klann
- Center for Neural Science, New York University, New York, NY10003
| | - Nahum Sonenberg
- Department of Biochemistry, McGill University, Montréal, QCH3G1Y6, Canada
- Rosalind and Morris Goodman Cancer Institute, McGill University, Montréal, QCH3A1A3, Canada
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9
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Madhwani KR, Sayied S, Ogata CH, Hogan CA, Lentini JM, Mallik M, Dumouchel JL, Storkebaum E, Fu D, O’Connor-Giles KM. tRNA modification enzyme-dependent redox homeostasis regulates synapse formation and memory. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.11.14.566895. [PMID: 38014328 PMCID: PMC10680711 DOI: 10.1101/2023.11.14.566895] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2023]
Abstract
Post-transcriptional modification of RNA regulates gene expression at multiple levels. ALKBH8 is a tRNA modifying enzyme that methylates wobble uridines in specific tRNAs to modulate translation. Through methylation of tRNA-selenocysteine, ALKBH8 promotes selenoprotein synthesis and regulates redox homeostasis. Pathogenic variants in ALKBH8 have been linked to intellectual disability disorders in the human population, but the role of ALKBH8 in the nervous system is unknown. Through in vivo studies in Drosophila, we show that ALKBH8 controls oxidative stress in the brain to restrain synaptic growth and support learning and memory. ALKBH8 null animals lack wobble uridine methylation and exhibit a global reduction in protein synthesis, including a specific decrease in selenoprotein levels. Loss of ALKBH8 or independent disruption of selenoprotein synthesis results in ectopic synapse formation. Genetic expression of antioxidant enzymes fully suppresses synaptic overgrowth in ALKBH8 null animals, confirming oxidative stress as the underlying cause of dysregulation. ALKBH8 animals also exhibit associative learning and memory impairments that are reversed by pharmacological antioxidant treatment. Together, these findings demonstrate the critical role of tRNA modification in redox homeostasis in the nervous system and reveal antioxidants as a potential therapy for ALKBH8-associated intellectual disability.
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Affiliation(s)
| | - Shanzeh Sayied
- Department of Neuroscience, Brown University, Providence, RI, USA
| | | | - Caley A. Hogan
- Laboratory of Genetics, University of Wisconsin-Madison, Madison, WI, USA
| | - Jenna M. Lentini
- Department of Biology, Center for RNA Biology, University of Rochester, Rochester, NY, USA
| | - Moushami Mallik
- Molecular Neurobiology Laboratory, Donders Institute for Brain, Cognition, and Behaviour, Radboud University, Nijmegen, NL
| | | | - Erik Storkebaum
- Molecular Neurobiology Laboratory, Donders Institute for Brain, Cognition, and Behaviour, Radboud University, Nijmegen, NL
| | - Dragony Fu
- Department of Biology, Center for RNA Biology, University of Rochester, Rochester, NY, USA
| | - Kate M. O’Connor-Giles
- Department of Neuroscience, Brown University, Providence, RI, USA
- Carney Institute for Brain Sciences, Brown University, Providence, RI, USA
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10
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Xie L, Sheehy RN, Xiong Y, Muneer A, Wrobel JA, Park KS, Velez J, Liu J, Luo YJ, Li YD, Quintanilla L, Li Y, Xu C, Deshmukh M, Wen Z, Jin J, Song J, Chen X. Novel brain-penetrant inhibitor of G9a methylase blocks Alzheimer's disease proteopathology for precision medication. MEDRXIV : THE PREPRINT SERVER FOR HEALTH SCIENCES 2023:2023.10.25.23297491. [PMID: 37961307 PMCID: PMC10635198 DOI: 10.1101/2023.10.25.23297491] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2023]
Abstract
Current amyloid beta-targeting approaches for Alzheimer's disease (AD) therapeutics only slow cognitive decline for small numbers of patients. This limited efficacy exists because AD is a multifactorial disease whose pathological mechanism(s) and diagnostic biomarkers are largely unknown. Here we report a new mechanism of AD pathogenesis in which the histone methyltransferase G9a noncanonically regulates translation of a hippocampal proteome that defines the proteopathic nature of AD. Accordingly, we developed a novel brain-penetrant inhibitor of G9a, MS1262, across the blood-brain barrier to block this G9a-regulated, proteopathologic mechanism. Intermittent MS1262 treatment of multiple AD mouse models consistently restored both cognitive and noncognitive functions to healthy levels. Comparison of proteomic/phosphoproteomic analyses of MS1262-treated AD mice with human AD patient data identified multiple pathological brain pathways that elaborate amyloid beta and neurofibrillary tangles as well as blood coagulation, from which biomarkers of early stage of AD including SMOC1 were found to be affected by MS1262 treatment. Notably, these results indicated that MS1262 treatment may reduce or avoid the risk of blood clot burst for brain bleeding or a stroke. This mouse-to-human conservation of G9a-translated AD proteopathology suggests that the global, multifaceted effects of MS1262 in mice could extend to relieve all symptoms of AD patients with minimum side effect. In addition, our mechanistically derived biomarkers can be used for stage-specific AD diagnosis and companion diagnosis of individualized drug effects. One-Sentence Summary A brain-penetrant inhibitor of G9a methylase blocks G9a translational mechanism to reverse Alzheimer's disease related proteome for effective therapy.
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11
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Okreglak V, Ling R, Ingaramo M, Thayer NH, Millett-Sikking A, Gottschling DE. Cell cycle-linked vacuolar pH dynamics regulate amino acid homeostasis and cell growth. Nat Metab 2023; 5:1803-1819. [PMID: 37640943 PMCID: PMC10590757 DOI: 10.1038/s42255-023-00872-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/03/2022] [Accepted: 07/21/2023] [Indexed: 08/31/2023]
Abstract
Amino acid homeostasis is critical for many cellular processes. It is well established that amino acids are compartmentalized using pH gradients generated between organelles and the cytoplasm; however, the dynamics of this partitioning has not been explored. Here we develop a highly sensitive pH reporter and find that the major amino acid storage compartment in Saccharomyces cerevisiae, the lysosome-like vacuole, alkalinizes before cell division and re-acidifies as cells divide. The vacuolar pH dynamics require the uptake of extracellular amino acids and activity of TORC1, the v-ATPase and the cycling of the vacuolar specific lipid phosphatidylinositol 3,5-bisphosphate, which is regulated by the cyclin-dependent kinase Pho85 (CDK5 in mammals). Vacuolar pH regulation enables amino acid sequestration and mobilization from the organelle, which is important for mitochondrial function, ribosome homeostasis and cell size control. Collectively, our data provide a new paradigm for the use of dynamic pH-dependent amino acid compartmentalization during cell growth/division.
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Affiliation(s)
- Voytek Okreglak
- Calico Life Sciences, LLC, South San Francisco, CA, USA.
- Altos Labs, Redwood City, CA, USA.
| | - Rachel Ling
- Calico Life Sciences, LLC, South San Francisco, CA, USA
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de Diego-Garcia L, Brennan GP, Auer T, Menendez-Mendez A, Parras A, Martin-Gil A, Mitra M, Ollà I, Villalba-Benito L, Gil B, Alves M, Lau K, Delanty N, Beausang A, Cryan J, Brett FM, Farrell MA, O'Brien DF, Mendez R, Carracedo-Rodríguez G, Henshall DC, Lucas JJ, Engel T. CPEB4-CLOCK crosstalk during temporal lobe epilepsy. Epilepsia 2023; 64:2827-2840. [PMID: 37543852 DOI: 10.1111/epi.17736] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2023] [Revised: 08/02/2023] [Accepted: 08/03/2023] [Indexed: 08/07/2023]
Abstract
OBJECTIVE Posttranscriptional mechanisms are increasingly recognized as important contributors to the formation of hyperexcitable networks in epilepsy. Messenger RNA (mRNA) polyadenylation is a key regulatory mechanism governing protein expression by enhancing mRNA stability and translation. Previous studies have shown large-scale changes in mRNA polyadenylation in the hippocampus of mice during epilepsy development. The cytoplasmic polyadenylation element-binding protein CPEB4 was found to drive epilepsy-induced poly(A) tail changes, and mice lacking CPEB4 develop a more severe seizure and epilepsy phenotype. The mechanisms controlling CPEB4 function and the downstream pathways that influence the recurrence of spontaneous seizures in epilepsy remain poorly understood. METHODS Status epilepticus was induced in wild-type and CPEB4-deficient male mice via an intra-amygdala microinjection of kainic acid. CLOCK binding to the CPEB4 promoter was analyzed via chromatin immunoprecipitation assay and melatonin levels via high-performance liquid chromatography in plasma. RESULTS Here, we show increased binding of CLOCK to recognition sites in the CPEB4 promoter region during status epilepticus in mice and increased Cpeb4 mRNA levels in N2A cells overexpressing CLOCK. Bioinformatic analysis of CPEB4-dependent genes undergoing changes in their poly(A) tail during epilepsy found that genes involved in the regulation of circadian rhythms are particularly enriched. Clock transcripts displayed a longer poly(A) tail length in the hippocampus of mice post-status epilepticus and during epilepsy. Moreover, CLOCK expression was increased in the hippocampus in mice post-status epilepticus and during epilepsy, and in resected hippocampus and cortex of patients with drug-resistant temporal lobe epilepsy. Furthermore, CPEB4 is required for CLOCK expression after status epilepticus, with lower levels in CPEB4-deficient compared to wild-type mice. Last, CPEB4-deficient mice showed altered circadian function, including altered melatonin blood levels and altered clustering of spontaneous seizures during the day. SIGNIFICANCE Our results reveal a new positive transcriptional-translational feedback loop involving CPEB4 and CLOCK, which may contribute to the regulation of the sleep-wake cycle during epilepsy.
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Affiliation(s)
- Laura de Diego-Garcia
- Department of Physiology and Medical Physics, Royal College of Surgeons in Ireland, University of Medicine and Health Sciences, Dublin, Ireland, RCSI University of Medicine and Health Sciences, Dublin, Ireland
- Ocupharm Group Research, Faculty of Optics and Optometry, University Complutense of Madrid, Madrid, Spain
| | - Gary P Brennan
- School of Biomolecular and Biomedical Science, UCD Conway Institute, University College Dublin, Dublin, Ireland
- FutureNeuro, Science Foundation Ireland Research Centre for Chronic and Rare Neurological Diseases, Royal College of Surgeons in Ireland, University of Medicine and Health Sciences, Dublin, Ireland
| | - Theresa Auer
- School of Biomolecular and Biomedical Science, UCD Conway Institute, University College Dublin, Dublin, Ireland
| | - Aida Menendez-Mendez
- Department of Physiology and Medical Physics, Royal College of Surgeons in Ireland, University of Medicine and Health Sciences, Dublin, Ireland, RCSI University of Medicine and Health Sciences, Dublin, Ireland
| | - Alberto Parras
- Department of Physiology and Medical Physics, Royal College of Surgeons in Ireland, University of Medicine and Health Sciences, Dublin, Ireland, RCSI University of Medicine and Health Sciences, Dublin, Ireland
- Center for Molecular Biology "Severo Ochoa," Spanish National Research Council/Autonomous University of Madrid, Madrid, Spain, Centro de Biología Molecular Severo Ochoa, CSIC/UAM, Madrid, Spain
| | - Alba Martin-Gil
- Ocupharm Group Research, Faculty of Optics and Optometry, University Complutense of Madrid, Madrid, Spain
| | - Meghma Mitra
- Department of Physiology and Medical Physics, Royal College of Surgeons in Ireland, University of Medicine and Health Sciences, Dublin, Ireland, RCSI University of Medicine and Health Sciences, Dublin, Ireland
| | - Ivana Ollà
- Center for Molecular Biology "Severo Ochoa," Spanish National Research Council/Autonomous University of Madrid, Madrid, Spain, Centro de Biología Molecular Severo Ochoa, CSIC/UAM, Madrid, Spain
- Networking Research Center on Neurodegenerative Diseases, Instituto de Salud Carlos III, Madrid, Spain
| | - Leticia Villalba-Benito
- School of Biomolecular and Biomedical Science, UCD Conway Institute, University College Dublin, Dublin, Ireland
- FutureNeuro, Science Foundation Ireland Research Centre for Chronic and Rare Neurological Diseases, Royal College of Surgeons in Ireland, University of Medicine and Health Sciences, Dublin, Ireland
| | - Beatriz Gil
- Department of Physiology and Medical Physics, Royal College of Surgeons in Ireland, University of Medicine and Health Sciences, Dublin, Ireland, RCSI University of Medicine and Health Sciences, Dublin, Ireland
| | - Mariana Alves
- Department of Physiology and Medical Physics, Royal College of Surgeons in Ireland, University of Medicine and Health Sciences, Dublin, Ireland, RCSI University of Medicine and Health Sciences, Dublin, Ireland
| | - Kelvin Lau
- Department of Physiology and Medical Physics, Royal College of Surgeons in Ireland, University of Medicine and Health Sciences, Dublin, Ireland, RCSI University of Medicine and Health Sciences, Dublin, Ireland
- FutureNeuro, Science Foundation Ireland Research Centre for Chronic and Rare Neurological Diseases, Royal College of Surgeons in Ireland, University of Medicine and Health Sciences, Dublin, Ireland
| | - Norman Delanty
- FutureNeuro, Science Foundation Ireland Research Centre for Chronic and Rare Neurological Diseases, Royal College of Surgeons in Ireland, University of Medicine and Health Sciences, Dublin, Ireland
- School of Pharmacy and Biomolecular Sciences, Royal College of Surgeons in Ireland, University of Medicine and Health Sciences, Dublin, Ireland
- Beaumont Hospital, Dublin, Ireland
| | | | | | | | | | | | - Raúl Mendez
- Institute for Research in Biomedicine, Barcelona Institute of Science and Technology, Barcelona, Spain
- Institució Catalana de Recerca i Estudis Avançats, Barcelona, Spain
| | | | - David C Henshall
- Department of Physiology and Medical Physics, Royal College of Surgeons in Ireland, University of Medicine and Health Sciences, Dublin, Ireland, RCSI University of Medicine and Health Sciences, Dublin, Ireland
- FutureNeuro, Science Foundation Ireland Research Centre for Chronic and Rare Neurological Diseases, Royal College of Surgeons in Ireland, University of Medicine and Health Sciences, Dublin, Ireland
| | - José J Lucas
- Center for Molecular Biology "Severo Ochoa," Spanish National Research Council/Autonomous University of Madrid, Madrid, Spain, Centro de Biología Molecular Severo Ochoa, CSIC/UAM, Madrid, Spain
- Networking Research Center on Neurodegenerative Diseases, Instituto de Salud Carlos III, Madrid, Spain
| | - Tobias Engel
- Department of Physiology and Medical Physics, Royal College of Surgeons in Ireland, University of Medicine and Health Sciences, Dublin, Ireland, RCSI University of Medicine and Health Sciences, Dublin, Ireland
- FutureNeuro, Science Foundation Ireland Research Centre for Chronic and Rare Neurological Diseases, Royal College of Surgeons in Ireland, University of Medicine and Health Sciences, Dublin, Ireland
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Harrer P, Škorvánek M, Kittke V, Dzinovic I, Borngräber F, Thomsen M, Mandel V, Svorenova T, Ostrozovicova M, Kulcsarova K, Berutti R, Busch H, Ott F, Kopajtich R, Prokisch H, Kumar KR, Mencacci NE, Kurian MA, Di Fonzo A, Boesch S, Kühn AA, Blümlein U, Lohmann K, Haslinger B, Weise D, Jech R, Winkelmann J, Zech M. Dystonia Linked to EIF4A2 Haploinsufficiency: A Disorder of Protein Translation Dysfunction. Mov Disord 2023; 38:1914-1924. [PMID: 37485550 DOI: 10.1002/mds.29562] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2023] [Revised: 06/06/2023] [Accepted: 07/05/2023] [Indexed: 07/25/2023] Open
Abstract
BACKGROUND Protein synthesis is a tightly controlled process, involving a host of translation-initiation factors and microRNA-associated repressors. Variants in the translational regulator EIF2AK2 were first linked to neurodevelopmental-delay phenotypes, followed by their implication in dystonia. Recently, de novo variants in EIF4A2, encoding eukaryotic translation initiation factor 4A isoform 2 (eIF4A2), have been described in pediatric cases with developmental delay and intellectual disability. OBJECTIVE We sought to characterize the role of EIF4A2 variants in dystonic conditions. METHODS We undertook an unbiased search for likely deleterious variants in mutation-constrained genes among 1100 families studied with dystonia. Independent cohorts were screened for EIF4A2 variants. Western blotting and immunocytochemical studies were performed in patient-derived fibroblasts. RESULTS We report the discovery of a novel heterozygous EIF4A2 frameshift deletion (c.896_897del) in seven patients from two unrelated families. The disease was characterized by adolescence- to adulthood-onset dystonia with tremor. In patient-derived fibroblasts, eIF4A2 production amounted to only 50% of the normal quantity. Reduction of eIF4A2 was associated with abnormally increased levels of IMP1, a target of Ccr4-Not, the complex that interacts with eIF4A2 to mediate microRNA-dependent translational repression. By complementing the analyses with fibroblasts bearing EIF4A2 biallelic mutations, we established a correlation between IMP1 expression alterations and eIF4A2 functional dosage. Moreover, eIF4A2 and Ccr4-Not displayed significantly diminished colocalization in dystonia patient cells. Review of international databases identified EIF4A2 deletion variants (c.470_472del, c.1144_1145del) in another two dystonia-affected pedigrees. CONCLUSIONS Our findings demonstrate that EIF4A2 haploinsufficiency underlies a previously unrecognized dominant dystonia-tremor syndrome. The data imply that translational deregulation is more broadly linked to both early neurodevelopmental phenotypes and later-onset dystonic conditions. © 2023 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.
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Affiliation(s)
- Philip Harrer
- Institute of Neurogenomics, Helmholtz Zentrum München, Munich, Germany
- Institute of Human Genetics, School of Medicine, Technical University of Munich, Munich, Germany
| | - Matej Škorvánek
- Department of Neurology, P.J. Safarik University, Kosice, Slovak Republic
- Department of Neurology, University Hospital of L. Pasteur, Kosice, Slovak Republic
| | - Volker Kittke
- Institute of Neurogenomics, Helmholtz Zentrum München, Munich, Germany
- Institute of Human Genetics, School of Medicine, Technical University of Munich, Munich, Germany
| | - Ivana Dzinovic
- Institute of Neurogenomics, Helmholtz Zentrum München, Munich, Germany
- Institute of Human Genetics, School of Medicine, Technical University of Munich, Munich, Germany
| | - Friederike Borngräber
- Movement Disorder and Neuromodulation Unit, Department of Neurology, Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Mirja Thomsen
- Institute of Neurogenetics, University of Lübeck, Lübeck, Germany
| | - Vanessa Mandel
- Institute of Neurogenomics, Helmholtz Zentrum München, Munich, Germany
| | - Tatiana Svorenova
- Department of Neurology, P.J. Safarik University, Kosice, Slovak Republic
- Department of Neurology, University Hospital of L. Pasteur, Kosice, Slovak Republic
| | - Miriam Ostrozovicova
- Department of Neurology, P.J. Safarik University, Kosice, Slovak Republic
- Department of Neurology, University Hospital of L. Pasteur, Kosice, Slovak Republic
| | - Kristina Kulcsarova
- Department of Neurology, P.J. Safarik University, Kosice, Slovak Republic
- Department of Neurology, University Hospital of L. Pasteur, Kosice, Slovak Republic
| | - Riccardo Berutti
- Institute of Neurogenomics, Helmholtz Zentrum München, Munich, Germany
- Institute of Human Genetics, School of Medicine, Technical University of Munich, Munich, Germany
| | - Hauke Busch
- Institute of Experimental Dermatology and Institute of Cardiogenetics, University of Lübeck, Lübeck, Germany
| | - Fabian Ott
- Institute of Experimental Dermatology and Institute of Cardiogenetics, University of Lübeck, Lübeck, Germany
| | - Robert Kopajtich
- Institute of Neurogenomics, Helmholtz Zentrum München, Munich, Germany
- Institute of Human Genetics, School of Medicine, Technical University of Munich, Munich, Germany
| | - Holger Prokisch
- Institute of Neurogenomics, Helmholtz Zentrum München, Munich, Germany
- Institute of Human Genetics, School of Medicine, Technical University of Munich, Munich, Germany
| | - Kishore R Kumar
- Translational Neurogenomics Group, Molecular Medicine Laboratory and Neurology Department, Concord Clinical School, Concord Repatriation General Hospital, The University of Sydney, Sydney, New South Wales, Australia
- Garvan Institute of Medical Research, Darlinghurst, New South Wales, Australia
| | - Niccolo E Mencacci
- Ken and Ruth Davee Department of Neurology, Simpson Querrey Center for Neurogenetics, Northwestern University, Feinberg School of Medicine, Chicago, Illinois, USA
| | - Manju A Kurian
- Department of Developmental Neurosciences, UCL Great Ormond Street Institute of Child Health, London, UK
- Department of Neurology, Great Ormond Street Hospital, London, UK
| | - Alessio Di Fonzo
- Foundation IRCCS Ca' Granda Ospedale Maggiore Policlinico, Neurology Unit, Milan, Italy
| | - Sylvia Boesch
- Department of Neurology, Medical University of Innsbruck, Innsbruck, Austria
| | - Andrea A Kühn
- Movement Disorder and Neuromodulation Unit, Department of Neurology, Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Ulrike Blümlein
- Department of Pediatrics, Carl-Thiem-Klinikum Cottbus, Cottbus, Germany
| | - Katja Lohmann
- Institute of Neurogenetics, University of Lübeck, Lübeck, Germany
| | - Bernhard Haslinger
- Department of Neurology, Klinikum rechts der Isar, Technical University of Munich, School of Medicine, Munich, Germany
| | - David Weise
- Department of Neurology, Asklepios Fachklinikum Stadtroda, Stadtroda, Germany
- Department of Neurology, University of Leipzig, Leipzig, Germany
| | - Robert Jech
- Department of Neurology, Charles University in Prague, 1st Faculty of Medicine and General University Hospital in Prague, Prague, Czech Republic
| | - Juliane Winkelmann
- Institute of Neurogenomics, Helmholtz Zentrum München, Munich, Germany
- Institute of Human Genetics, School of Medicine, Technical University of Munich, Munich, Germany
- Lehrstuhl für Neurogenetik, Technische Universität München, Munich, Germany
- Munich Cluster for Systems Neurology, SyNergy, Munich, Germany
| | - Michael Zech
- Institute of Neurogenomics, Helmholtz Zentrum München, Munich, Germany
- Institute of Human Genetics, School of Medicine, Technical University of Munich, Munich, Germany
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14
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Santos JL, Petsidou E, Saraogi P, Bartsch U, Gerber AP, Seibt J. Effect of Acute Enriched Environment Exposure on Brain Oscillations and Activation of the Translation Initiation Factor 4E-BPs at Synapses across Wakefulness and Sleep in Rats. Cells 2023; 12:2320. [PMID: 37759542 PMCID: PMC10528220 DOI: 10.3390/cells12182320] [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: 07/31/2023] [Revised: 09/15/2023] [Accepted: 09/18/2023] [Indexed: 09/29/2023] Open
Abstract
Brain plasticity is induced by learning during wakefulness and is consolidated during sleep. But the molecular mechanisms involved are poorly understood and their relation to experience-dependent changes in brain activity remains to be clarified. Localised mRNA translation is important for the structural changes at synapses supporting brain plasticity consolidation. The translation mTOR pathway, via phosphorylation of 4E-BPs, is known to be activate during sleep and contributes to brain plasticity, but whether this activation is specific to synapses is not known. We investigated this question using acute exposure of rats to an enriched environment (EE). We measured brain activity with EEGs and 4E-BP phosphorylation at cortical and cerebellar synapses with Western blot analyses. Sleep significantly increased the conversion of 4E-BPs to their hyperphosphorylated forms at synapses, especially after EE exposure. EE exposure increased oscillations in the alpha band during active exploration and in the theta-to-beta (4-30 Hz) range, as well as spindle density, during NREM sleep. Theta activity during exploration and NREM spindle frequency predicted changes in 4E-BP hyperphosphorylation at synapses. Hence, our results suggest a functional link between EEG and molecular markers of plasticity across wakefulness and sleep.
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Affiliation(s)
- José Lucas Santos
- Surrey Sleep Research Centre, School of Biosciences, Faculty of Health and Medical Sciences, University of Surrey, Guildford GU2 7XP, UK; (J.L.S.); (U.B.)
- Department of Microbial Sciences, School of Biosciences, Faculty of Health and Medical Sciences, University of Surrey, Guildford GU2 7XH, UK;
- Department of Physiology, Development and Neuroscience, University of Cambridge, Physiological Laboratory, Downing Street, Cambridge CB2 3EG, UK
| | - Evlalia Petsidou
- Undergraduate Programme in Biological Science, University of Surrey, Guildford GU2 7XH, UK
- Postgraduate Programme in Neuroscience (MSc), Cyprus Institute of Neurology and Genetics, Iroon Avenue 6, Egkomi 2371, Cyprus
| | - Pallavi Saraogi
- Undergraduate Programme in Biological Science, University of Surrey, Guildford GU2 7XH, UK
| | - Ullrich Bartsch
- Surrey Sleep Research Centre, School of Biosciences, Faculty of Health and Medical Sciences, University of Surrey, Guildford GU2 7XP, UK; (J.L.S.); (U.B.)
- UK Dementia Research Institute, Care Research & Technology Centre at Imperial College London and University of Surrey, Guildford GU2 7XH, UK
| | - André P. Gerber
- Department of Microbial Sciences, School of Biosciences, Faculty of Health and Medical Sciences, University of Surrey, Guildford GU2 7XH, UK;
| | - Julie Seibt
- Surrey Sleep Research Centre, School of Biosciences, Faculty of Health and Medical Sciences, University of Surrey, Guildford GU2 7XP, UK; (J.L.S.); (U.B.)
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15
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Gebert M, Sławski J, Kalinowski L, Collawn JF, Bartoszewski R. The Unfolded Protein Response: A Double-Edged Sword for Brain Health. Antioxidants (Basel) 2023; 12:1648. [PMID: 37627643 PMCID: PMC10451475 DOI: 10.3390/antiox12081648] [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: 07/26/2023] [Revised: 08/14/2023] [Accepted: 08/19/2023] [Indexed: 08/27/2023] Open
Abstract
Efficient brain function requires as much as 20% of the total oxygen intake to support normal neuronal cell function. This level of oxygen usage, however, leads to the generation of free radicals, and thus can lead to oxidative stress and potentially to age-related cognitive decay and even neurodegenerative diseases. The regulation of this system requires a complex monitoring network to maintain proper oxygen homeostasis. Furthermore, the high content of mitochondria in the brain has elevated glucose demands, and thus requires a normal redox balance. Maintaining this is mediated by adaptive stress response pathways that permit cells to survive oxidative stress and to minimize cellular damage. These stress pathways rely on the proper function of the endoplasmic reticulum (ER) and the activation of the unfolded protein response (UPR), a cellular pathway responsible for normal ER function and cell survival. Interestingly, the UPR has two opposing signaling pathways, one that promotes cell survival and one that induces apoptosis. In this narrative review, we discuss the opposing roles of the UPR signaling pathways and how a better understanding of these stress pathways could potentially allow for the development of effective strategies to prevent age-related cognitive decay as well as treat neurodegenerative diseases.
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Affiliation(s)
- Magdalena Gebert
- Department of Medical Laboratory Diagnostics—Fahrenheit Biobank BBMRI.pl, Medical University of Gdansk, 80-134 Gdansk, Poland
| | - Jakub Sławski
- Department of Biophysics, Faculty of Biotechnology, University of Wroclaw, F. Joliot-Curie 14a Street, 50-383 Wroclaw, Poland
| | - Leszek Kalinowski
- Department of Medical Laboratory Diagnostics—Fahrenheit Biobank BBMRI.pl, Medical University of Gdansk, 80-134 Gdansk, Poland
- BioTechMed Centre, Department of Mechanics of Materials and Structures, Gdansk University of Technology, 11/12 Narutowicza Street, 80-233 Gdansk, Poland
| | - James F. Collawn
- Department of Cell, Developmental, and Integrative Biology, University of Alabama at Birmingham, Birmingham, AL 35233, USA
| | - Rafal Bartoszewski
- Department of Biophysics, Faculty of Biotechnology, University of Wroclaw, F. Joliot-Curie 14a Street, 50-383 Wroclaw, Poland
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Ament SA, Poulopoulos A. The brain's dark transcriptome: Sequencing RNA in distal compartments of neurons and glia. Curr Opin Neurobiol 2023; 81:102725. [PMID: 37196598 PMCID: PMC10524153 DOI: 10.1016/j.conb.2023.102725] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2022] [Revised: 03/22/2023] [Accepted: 04/02/2023] [Indexed: 05/19/2023]
Abstract
Transcriptomic approaches are powerful strategies to map the molecular diversity of cells in the brain. Single-cell genomic atlases have now been compiled for entire mammalian brains. However, complementary techniques are only just beginning to map the subcellular transcriptomes from distal cellular compartments. We review single-cell datasets alongside subtranscriptome data from the mammalian brain to explore the development of cellular and subcellular diversity. We discuss how single-cell RNA-seq misses transcripts localized away from cell bodies, which form the 'dark transcriptome' of the brain: a collection of subtranscriptomes in dendrites, axons, growth cones, synapses, and endfeet with important roles in brain development and function. Recent advances in subcellular transcriptome sequencing are beginning to reveal these elusive pools of RNA. We outline the success stories to date in uncovering the constituent subtranscriptomes of neurons and glia, as well as present the emerging toolkit that is accelerating the pace of subtranscriptome discovery.
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Affiliation(s)
- Seth A Ament
- Department of Psychiatry, UM-MIND, and Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Alexandros Poulopoulos
- Department of Pharmacology and UM-MIND, University of Maryland School of Medicine, Baltimore, MD, USA.
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17
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Varesi A, Campagnoli LIM, Barbieri A, Rossi L, Ricevuti G, Esposito C, Chirumbolo S, Marchesi N, Pascale A. RNA binding proteins in senescence: A potential common linker for age-related diseases? Ageing Res Rev 2023; 88:101958. [PMID: 37211318 DOI: 10.1016/j.arr.2023.101958] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2023] [Revised: 05/09/2023] [Accepted: 05/18/2023] [Indexed: 05/23/2023]
Abstract
Aging represents the major risk factor for the onset and/or progression of various disorders including neurodegenerative diseases, metabolic disorders, and bone-related defects. As the average age of the population is predicted to exponentially increase in the coming years, understanding the molecular mechanisms underlying the development of aging-related diseases and the discovery of new therapeutic approaches remain pivotal. Well-reported hallmarks of aging are cellular senescence, genome instability, autophagy impairment, mitochondria dysfunction, dysbiosis, telomere attrition, metabolic dysregulation, epigenetic alterations, low-grade chronic inflammation, stem cell exhaustion, altered cell-to-cell communication and impaired proteostasis. With few exceptions, however, many of the molecular players implicated within these processes as well as their role in disease development remain largely unknown. RNA binding proteins (RBPs) are known to regulate gene expression by dictating at post-transcriptional level the fate of nascent transcripts. Their activity ranges from directing primary mRNA maturation and trafficking to modulation of transcript stability and/or translation. Accumulating evidence has shown that RBPs are emerging as key regulators of aging and aging-related diseases, with the potential to become new diagnostic and therapeutic tools to prevent or delay aging processes. In this review, we summarize the role of RBPs in promoting cellular senescence and we highlight their dysregulation in the pathogenesis and progression of the main aging-related diseases, with the aim of encouraging further investigations that will help to better disclose this novel and captivating molecular scenario.
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Affiliation(s)
- Angelica Varesi
- Department of Biology and Biotechnology, University of Pavia, Pavia, Italy.
| | | | - Annalisa Barbieri
- Department of Drug Sciences, Section of Pharmacology, University of Pavia, Pavia, Italy
| | - Lorenzo Rossi
- Institute of Molecular Biology and Biophysics, ETH Zurich, Zurich, Switzerland
| | | | - Ciro Esposito
- Department of Internal Medicine and Therapeutics, University of Pavia, Italy; Nephrology and dialysis unit, ICS S. Maugeri SPA SB Hospital, Pavia, Italy; High School in Geriatrics, University of Pavia, Italy
| | | | - Nicoletta Marchesi
- Department of Drug Sciences, Section of Pharmacology, University of Pavia, Pavia, Italy
| | - Alessia Pascale
- Department of Drug Sciences, Section of Pharmacology, University of Pavia, Pavia, Italy.
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18
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Piserchio A, Long K, Browning L, Bohanon A, Isiorho E, Dalby K, Ghose R. ADP enhances the allosteric activation of eukaryotic elongation factor 2 kinase by calmodulin. Proc Natl Acad Sci U S A 2023; 120:e2300902120. [PMID: 37068230 PMCID: PMC10151598 DOI: 10.1073/pnas.2300902120] [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: 01/16/2023] [Accepted: 03/06/2023] [Indexed: 04/19/2023] Open
Abstract
Protein translation, one of the most energy-consumptive processes in a eukaryotic cell, requires robust regulation, especially under energy-deprived conditions. A critical component of this regulation is the suppression of translational elongation through reduced ribosome association of the GTPase eukaryotic elongation factor 2 (eEF-2) resulting from its specific phosphorylation by the calmodulin (CaM)-activated α-kinase eEF-2 kinase (eEF-2K). It has been suggested that the eEF-2K response to reduced cellular energy levels is indirect and mediated by the universal energy sensor AMP-activated protein kinase (AMPK) through direct stimulatory phosphorylation and/or downregulation of the eEF-2K-inhibitory nutrient-sensing mTOR pathway. Here, we provide structural, biochemical, and cell-biological evidence of a direct energy-sensing role of eEF-2K through its stimulation by ADP. A crystal structure of the nucleotide-bound complex between CaM and the functional core of eEF-2K phosphorylated at its primary stimulatory site (T348) reveals ADP bound at a unique pocket located on the face opposite that housing the kinase active site. Within this basic pocket (BP), created at the CaM/eEF-2K interface upon complex formation, ADP is stabilized through numerous interactions with both interacting partners. Biochemical analyses using wild-type eEF-2K and specific BP mutants indicate that ADP stabilizes CaM within the active complex, increasing the sensitivity of the kinase to CaM. Induction of energy stress through glycolysis inhibition results in significantly reduced enhancement of phosphorylated eEF-2 levels in cells expressing ADP-binding compromised BP mutants compared to cells expressing wild-type eEF-2K. These results suggest a direct energy-sensing role for eEF-2K through its cooperative interaction with CaM and ADP.
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Affiliation(s)
- Andrea Piserchio
- Department of Chemistry and Biochemistry, The City College of New York, New York, NY10031
| | - Kimberly J. Long
- Division of Chemical Biology and Medicinal Chemistry, the University of Texas, Austin, TX78712
| | - Luke S. Browning
- Interdisciplinary Life Sciences Graduate Program, the University of Texas, Austin, TX78712
| | - Amanda L. Bohanon
- Interdisciplinary Life Sciences Graduate Program, the University of Texas, Austin, TX78712
| | - Eta A. Isiorho
- Macromolecular Crystallization Facility CUNY Advanced Science Research Center, New York, NY10031
| | - Kevin N. Dalby
- Division of Chemical Biology and Medicinal Chemistry, the University of Texas, Austin, TX78712
- Interdisciplinary Life Sciences Graduate Program, the University of Texas, Austin, TX78712
| | - Ranajeet Ghose
- Department of Chemistry and Biochemistry, The City College of New York, New York, NY10031
- PhD Program in Biochemistry, The Graduate Center of CUNY, New York, NY10016
- PhD Program in Chemistry, The Graduate Center of CUNY, New York, NY10016
- PhD Program in Physics, The Graduate Center of CUNY, New York, NY10016
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19
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Villalobos-Cantor S, Barrett RM, Condon AF, Arreola-Bustos A, Rodriguez KM, Cohen MS, Martin I. Rapid cell type-specific nascent proteome labeling in Drosophila. eLife 2023; 12:83545. [PMID: 37092974 PMCID: PMC10125018 DOI: 10.7554/elife.83545] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2022] [Accepted: 04/09/2023] [Indexed: 04/25/2023] Open
Abstract
Controlled protein synthesis is required to regulate gene expression and is often carried out in a cell type-specific manner. Protein synthesis is commonly measured by labeling the nascent proteome with amino acid analogs or isotope-containing amino acids. These methods have been difficult to implement in vivo as they require lengthy amino acid replacement procedures. O-propargyl-puromycin (OPP) is a puromycin analog that incorporates into nascent polypeptide chains. Through its terminal alkyne, OPP can be conjugated to a fluorophore-azide for directly visualizing nascent protein synthesis, or to a biotin-azide for capture and identification of newly-synthesized proteins. To achieve cell type-specific OPP incorporation, we developed phenylacetyl-OPP (PhAc-OPP), a puromycin analog harboring an enzyme-labile blocking group that can be removed by penicillin G acylase (PGA). Here, we show that cell type-specific PGA expression in Drosophila can be used to achieve OPP labeling of newly-synthesized proteins in targeted cell populations within the brain. Following a brief 2 hr incubation of intact brains with PhAc-OPP, we observe robust imaging and affinity purification of OPP-labeled nascent proteins in PGA-targeted cell populations. We apply this method to show a pronounced age-related decline in neuronal protein synthesis in the fly brain, demonstrating the capability of PhAc-OPP to quantitatively capture in vivo protein synthesis states. This method, which we call POPPi (PGA-dependent OPP incorporation), should be applicable for rapidly visualizing protein synthesis and identifying nascent proteins synthesized under diverse physiological and pathological conditions with cellular specificity in vivo.
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Affiliation(s)
- Stefanny Villalobos-Cantor
- Jungers Center for Neurosciences, Department of Neurology, Oregon Health and Science University, Portland, United States
| | - Ruth M Barrett
- Jungers Center for Neurosciences, Department of Neurology, Oregon Health and Science University, Portland, United States
| | - Alec F Condon
- Jungers Center for Neurosciences, Department of Neurology, Oregon Health and Science University, Portland, United States
| | - Alicia Arreola-Bustos
- Jungers Center for Neurosciences, Department of Neurology, Oregon Health and Science University, Portland, United States
| | - Kelsie M Rodriguez
- Department of Chemical Physiology and Biochemistry, Oregon Health and Science University, Portland, United States
| | - Michael S Cohen
- Department of Chemical Physiology and Biochemistry, Oregon Health and Science University, Portland, United States
| | - Ian Martin
- Jungers Center for Neurosciences, Department of Neurology, Oregon Health and Science University, Portland, United States
- Department of Chemical Physiology and Biochemistry, Oregon Health and Science University, Portland, United States
- Parkinson Center of Oregon, Oregon Health and Science University, Portland, United States
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20
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Anadolu MN, Sun J, Kailasam S, Chalkiadaki K, Krimbacher K, Li JTY, Markova T, Jafarnejad SM, Lefebvre F, Ortega J, Gkogkas CG, Sossin WS. Ribosomes in RNA Granules Are Stalled on mRNA Sequences That Are Consensus Sites for FMRP Association. J Neurosci 2023; 43:2440-2459. [PMID: 36849416 PMCID: PMC10082463 DOI: 10.1523/jneurosci.1002-22.2023] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2022] [Revised: 02/07/2023] [Accepted: 02/13/2023] [Indexed: 03/01/2023] Open
Abstract
Local translation in neurons is partly mediated by the reactivation of stalled polysomes. Stalled polysomes may be enriched within the granule fraction, defined as the pellet of sucrose gradients used to separate polysomes from monosomes. The mechanism of how elongating ribosomes are reversibly stalled and unstalled on mRNAs is still unclear. In the present study, we characterize the ribosomes in the granule fraction using immunoblotting, cryogenic electron microscopy (cryo-EM), and ribosome profiling. We find that this fraction, isolated from 5-d-old rat brains of both sexes, is enriched in proteins implicated in stalled polysome function, such as the fragile X mental retardation protein (FMRP) and Up-frameshift mutation 1 homologue. Cryo-EM analysis of ribosomes in this fraction indicates they are stalled, mainly in the hybrid state. Ribosome profiling of this fraction reveals (1) an enrichment for footprint reads of mRNAs that interact with FMRPs and are associated with stalled polysomes, (2) an abundance of footprint reads derived from mRNAs of cytoskeletal proteins implicated in neuronal development, and (3) increased ribosome occupancy on mRNAs encoding RNA binding proteins. Compared with those usually found in ribosome profiling studies, the footprint reads were longer and were mapped to reproducible peaks in the mRNAs. These peaks were enriched in motifs previously associated with mRNAs cross-linked to FMRP in vivo, independently linking the ribosomes in the granule fraction to the ribosomes associated with FMRP in the cell. The data supports a model in which specific sequences in mRNAs act to stall ribosomes during translation elongation in neurons.SIGNIFICANCE STATEMENT Neurons send mRNAs to synapses in RNA granules, where they are not translated until an appropriate stimulus is given. Here, we characterize a granule fraction obtained from sucrose gradients and show that polysomes in this fraction are stalled on consensus sequences in a specific state of translational arrest with extended ribosome-protected fragments. This finding greatly increases our understanding of how neurons use specialized mechanisms to regulate translation and suggests that many studies on neuronal translation may need to be re-evaluated to include the large fraction of neuronal polysomes found in the pellet of sucrose gradients used to isolate polysomes.
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Affiliation(s)
- Mina N Anadolu
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, Quebec H3A 2B4, Canada
| | - Jingyu Sun
- Department of Anatomy and Cell Biology, McGill University, Montreal, Quebec H3A 0C7, Canada
- Centre for Structural Biology, McGill University, Montreal, Quebec H3G 0B1, Canada
| | - Senthilkumar Kailasam
- Canadian Centre for Computational Genomics, McGill University, Montreal, Quebec H3A 0G1, Canada
| | - Kleanthi Chalkiadaki
- Biomedical Research Institute, Foundation for Research and Technology-Hellas, 45110 Ioannina, Greece
| | - Konstanze Krimbacher
- Department of Pharmacology, Medical University of Innsbruck, Innsbruck Austria Division of Biomedical Research, A-6020 Innsbruck, Austria
| | - Jewel T-Y Li
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, Quebec H3A 2B4, Canada
| | - Teodora Markova
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, Quebec H3A 2B4, Canada
| | - Seyed M Jafarnejad
- Patrick G, Johnston Centre for Cancer Research, Queen's University Belfast, Belfast, Northern Ireland BT9 7AE, United Kingdom
| | - Francois Lefebvre
- Canadian Centre for Computational Genomics, McGill University, Montreal, Quebec H3A 0G1, Canada
| | - Joaquin Ortega
- Department of Anatomy and Cell Biology, McGill University, Montreal, Quebec H3A 0C7, Canada
- Centre for Structural Biology, McGill University, Montreal, Quebec H3G 0B1, Canada
| | - Christos G Gkogkas
- Biomedical Research Institute, Foundation for Research and Technology-Hellas, 45110 Ioannina, Greece
| | - Wayne S Sossin
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, Quebec H3A 2B4, Canada
- Department of Anatomy and Cell Biology, McGill University, Montreal, Quebec H3A 0C7, Canada
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21
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Tajima Y, Ito K, Yuan Y, Frank MO, Saito Y, Darnell RB. NOVA1 acts on Impact to regulate hypothalamic function and translation in inhibitory neurons. Cell Rep 2023; 42:112050. [PMID: 36716149 PMCID: PMC10382602 DOI: 10.1016/j.celrep.2023.112050] [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: 09/13/2022] [Revised: 11/12/2022] [Accepted: 01/15/2023] [Indexed: 01/30/2023] Open
Abstract
We describe a patient haploinsufficient for the neuronal RNA binding protein NOVA1 who developed a behavioral motor hyperactivity disorder, suggesting a role of NOVA1 in postnatal motor inhibition. To investigate Nova1's action in adult Gad2+ inhibitory neurons, we generated a conditional Nova1-null mouse (Nova1-cKOGad2-cre). Strikingly, the phenotypes of these mice show many similarities to the NOVA1 haploinsufficient patient and identify a function of Nova1 in the hypothalamus. Molecularly, Nova1 loss in Gad2-positive neurons alters downstream expression of Impact mRNA, along with a subset of RNAs encoding electron transport chain-related factors and ribosomal proteins. NOVA1 stabilizes Impact mRNA by binding its 3' UTR, antagonizing the actions of miR-138 and miR-124. Together, these studies demonstrate actions of NOVA1 in adult hypothalamic neurons, mechanisms by which it functions in translation and metabolism, including through direct binding to Impact mRNA, and illuminate its role in human neurologic disease.
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Affiliation(s)
- Yoko Tajima
- Laboratory of Molecular Neuro-oncology, The Rockefeller University, 1230 York Avenue, New York, NY 10065, USA
| | - Keiichi Ito
- Laboratory of Biochemistry and Molecular Biology, The Rockefeller University, 1230 York Avenue, New York, NY 10065, USA
| | - Yuan Yuan
- Laboratory of Molecular Neuro-oncology, The Rockefeller University, 1230 York Avenue, New York, NY 10065, USA
| | - Mayu O Frank
- Laboratory of Molecular Neuro-oncology, The Rockefeller University, 1230 York Avenue, New York, NY 10065, USA
| | - Yuhki Saito
- Laboratory of Molecular Neuro-oncology, The Rockefeller University, 1230 York Avenue, New York, NY 10065, USA
| | - Robert B Darnell
- Laboratory of Molecular Neuro-oncology, The Rockefeller University, 1230 York Avenue, New York, NY 10065, USA; Howard Hughes Medical Institute, The Rockefeller University, New York, NY, USA.
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22
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Zhou X, Yang W, Wang X, Ma T. Isoform-specific effects of neuronal repression of the AMPK catalytic subunit on cognitive function in aged mice. Aging (Albany NY) 2023; 15:932-946. [PMID: 36842095 PMCID: PMC10008489 DOI: 10.18632/aging.204554] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2022] [Accepted: 02/20/2023] [Indexed: 02/27/2023]
Abstract
AMP-activated protein kinase (AMPK) functions as a molecular sensor that plays a critical role in maintaining cellular energy homeostasis. Dysregulation of the AMPK signaling has been linked to synaptic failure and cognitive impairments. Our recent study demonstrates abnormally increased AMPK activity in the hippocampus of aged mice. The kinase catalytic subunit of AMPK exists in two isoforms α1 and α2, and their specific roles in aging-related cognitive deficits are unknown. Taking advantage of the unique transgenic mice (AMPKα1/α2 cKO) recently developed by our group, we investigated how isoform-specific suppression of the neuronal AMPKα may contribute to the regulation of cognitive and synaptic function associated with aging. We found that aging-related impairment of long-term object recognition memory was improved with suppression of AMPKα1 but not AMPKα2 isoform. Moreover, aging-related spatial memory deficits were unaltered with suppression of either AMPKα isoform. Biochemical experiments showed that the phosphorylation levels of the eukaryotic initiation factor 2 α subunit (eIF2α) were specifically decreased in the hippocampus of the AMPKα1 cKO mice. We further performed large-scale unbiased proteomics analysis and revealed identities of proteins whose expression is differentially regulated with AMPKα isoform suppression. These novel findings may provide insights into the roles of AMPK signaling pathway in cognitive aging.
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Affiliation(s)
- Xueyan Zhou
- Department of Internal Medicine-Gerontology and Geriatric Medicine, Wake Forest University School of Medicine, Winston-Salem, NC 27157, USA
| | - Wenzhong Yang
- Department of Internal Medicine-Gerontology and Geriatric Medicine, Wake Forest University School of Medicine, Winston-Salem, NC 27157, USA
| | - Xin Wang
- Department of Internal Medicine-Gerontology and Geriatric Medicine, Wake Forest University School of Medicine, Winston-Salem, NC 27157, USA
| | - Tao Ma
- Department of Internal Medicine-Gerontology and Geriatric Medicine, Wake Forest University School of Medicine, Winston-Salem, NC 27157, USA.,Department of Physiology and Pharmacology, Wake Forest University School of Medicine, Winston-Salem, NC 27157, USA.,Department of Neurobiology and Anatomy, Wake Forest University School of Medicine, Winston-Salem, NC 27157, USA
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23
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Fusée L, Salomao N, Ponnuswamy A, Wang L, López I, Chen S, Gu X, Polyzoidis S, Vadivel Gnanasundram S, Fahraeus R. The p53 endoplasmic reticulum stress-response pathway evolved in humans but not in mice via PERK-regulated p53 mRNA structures. Cell Death Differ 2023; 30:1072-1081. [PMID: 36813920 PMCID: PMC10070458 DOI: 10.1038/s41418-023-01127-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2022] [Revised: 01/27/2023] [Accepted: 02/01/2023] [Indexed: 02/24/2023] Open
Abstract
Cellular stress conditions activate p53-dependent pathways to counteract the inflicted damage. To achieve the required functional diversity, p53 is subjected to numerous post-translational modifications and the expression of isoforms. Little is yet known how p53 has evolved to respond to different stress pathways. The p53 isoform p53/47 (p47 or ΔNp53) is linked to aging and neural degeneration and is expressed in human cells via an alternative cap-independent translation initiation from the 2nd in-frame AUG at codon 40 (+118) during endoplasmic reticulum (ER) stress. Despite an AUG codon in the same location, the mouse p53 mRNA does not express the corresponding isoform in either human or mouse-derived cells. High-throughput in-cell RNA structure probing shows that p47 expression is attributed to PERK kinase-dependent structural alterations in the human p53 mRNA, independently of eIF2α. These structural changes do not take place in murine p53 mRNA. Surprisingly, PERK response elements required for the p47 expression are located downstream of the 2nd AUG. The data show that the human p53 mRNA has evolved to respond to PERK-mediated regulation of mRNA structures in order to control p47 expression. The findings highlight how p53 mRNA co-evolved with the function of the encoded protein to specify p53-activities under different cellular conditions.
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Affiliation(s)
- Leila Fusée
- Inserm U1131, 27 Rue Juliette Dodu, 75010, Paris, France
| | - Norman Salomao
- Inserm U1131, 27 Rue Juliette Dodu, 75010, Paris, France
| | | | - Lixiao Wang
- Department of Medical Biosciences, Umea University, 90185, Umea, Sweden
| | - Ignacio López
- Biochemistry-Molecular Biology, Faculty of Science, Universidad de la República, Iguá 4225, 11400, Montevideo, Uruguay
| | - Sa Chen
- Department of Medical Biosciences, Umea University, 90185, Umea, Sweden
| | - Xiaolian Gu
- Department of Medical Biosciences, Umea University, 90185, Umea, Sweden
| | - Stavros Polyzoidis
- Department of Neurosurgery, AHEPA Hospital, Aristotle University of Thessaloniki, Thessaloniki, Greece
| | | | - Robin Fahraeus
- Inserm U1131, 27 Rue Juliette Dodu, 75010, Paris, France. .,Department of Medical Biosciences, Umea University, 90185, Umea, Sweden. .,RECAMO, Masaryk Memorial Cancer Institute, Zluty kopec 7, 65653, Brno, Czech Republic.
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24
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Wang X, Zhou X, Lee J, Furdui CM, Ma T. In-Depth Proteomic Analysis of De Novo Proteome in a Mouse Model of Alzheimer's Disease. J Alzheimers Dis 2023; 91:1471-1482. [PMID: 36641677 PMCID: PMC10016629 DOI: 10.3233/jad-221044] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
BACKGROUND Alzheimer's disease (AD) is the most common dementia syndrome in the elderly characterized by synaptic failure and unique brain pathology. De novo protein synthesis is required for the maintenance of memory and synaptic plasticity. Mounting evidence links impaired neuronal protein synthesis capacity and overall protein synthesis deficits to AD pathogenesis. Meanwhile, identities of AD-associated dysregulation of "newly synthesized proteome" remain elusive. OBJECTIVE To investigate de novo proteome alterations in the hippocampus of aged Tg19959 AD model mice. METHODS In this study, we combined the bioorthogonal noncanonical amino acid tagging (BONCAT) method with the unbiased large-scale proteomic analysis in acute living brain slices (we name it "BONSPEC") to investigate de novo proteome alterations in the hippocampus of Tg19959 AD model mice. We further applied multiple bioinformatics methods to analyze in-depth the proteomics data. RESULTS In total, 1,742 proteins were detected across the 10 samples with the BONSPEC method. After exclusion of those only detected in less than half of the samples in both groups, 1,362 proteins were kept for further analysis. 37 proteins were differentially expressed (based on statistical analysis) between the WT and Tg19959 groups. Among them, 19 proteins were significantly decreased while 18 proteins were significantly increased in the hippocampi of Tg19959 mice compared to WT mice. The results suggest that proteins involved in synaptic function were enriched in de novo proteome of AD mice. CONCLUSION Our study could provide insights into the future investigation into the molecular signaling mechanisms underlying AD and related dementias (ADRDs).
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Affiliation(s)
- Xin Wang
- Department of Internal Medicine, Gerontology and Geriatric Medicine, Wake Forest School of Medicine, Winston-Salem, NC, USA
| | - Xueyan Zhou
- Department of Internal Medicine, Gerontology and Geriatric Medicine, Wake Forest School of Medicine, Winston-Salem, NC, USA
| | - Jingyun Lee
- Department of Internal Medicine-Section on Molecular Medicine, Wake Forest University School of Medicine, Winston-Salem, NC, USA
| | - Cristina M Furdui
- Department of Internal Medicine-Section on Molecular Medicine, Wake Forest University School of Medicine, Winston-Salem, NC, USA
| | - Tao Ma
- Department of Internal Medicine, Gerontology and Geriatric Medicine, Wake Forest School of Medicine, Winston-Salem, NC, USA.,Department of Physiology and Pharmacology, Wake Forest School of Medicine, Winston-Salem, NC, USA.,Department of Neurobiology and Anatomy, Wake Forest School of Medicine, Winston-Salem, NC, USA
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25
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Zha C, Sossin WS. The molecular diversity of plasticity mechanisms underlying memory: An evolutionary perspective. J Neurochem 2022; 163:444-460. [PMID: 36326567 DOI: 10.1111/jnc.15717] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2022] [Revised: 08/29/2022] [Accepted: 10/17/2022] [Indexed: 11/06/2022]
Abstract
Experience triggers molecular cascades in organisms (learning) that lead to alterations (memory) to allow the organism to change its behavior based on experience. Understanding the molecular mechanisms underlying memory, particularly in the nervous system of animals, has been an exciting scientific challenge for neuroscience. We review what is known about forms of neuronal plasticity that underlie memory highlighting important issues in the field: (1) the importance of being able to measure how neurons are activated during learning to identify the form of plasticity that underlies memory, (2) the many distinct forms of plasticity important for memories that naturally decay both within and between organisms, and (3) unifying principles underlying the formation and maintenance of long-term memories. Overall, the diversity of molecular mechanisms underlying memories that naturally decay contrasts with more unified molecular mechanisms implicated in long-lasting changes. Despite many advances, important questions remain as to which mechanisms of neuronal plasticity underlie memory.
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Affiliation(s)
- Congyao Zha
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, Quebec, Canada
| | - Wayne S Sossin
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, Quebec, Canada
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26
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Ma X, Li L, Li Z, Huang Z, Yang Y, Liu P, Guo D, Li Y, Wu T, Luo R, Xu J, Ye W, Jiang B, Shi L. eEF2 in the prefrontal cortex promotes excitatory synaptic transmission and social novelty behavior. EMBO Rep 2022; 23:e54543. [PMID: 35993189 PMCID: PMC9535807 DOI: 10.15252/embr.202154543] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2021] [Revised: 07/22/2022] [Accepted: 08/03/2022] [Indexed: 08/24/2023] Open
Abstract
Regulation of mRNA translation is essential for brain development and function. Translation elongation factor eEF2 acts as a molecular hub orchestrating various synaptic signals to protein synthesis control and participates in hippocampus-dependent cognitive functions. However, whether eEF2 regulates other behaviors in different brain regions has been unknown. Here, we construct a line of Eef2 heterozygous (HET) mice, which show a reduction in eEF2 and protein synthesis mainly in excitatory neurons of the prefrontal cortex. The mice also show lower spine density, reduced excitability, and AMPAR-mediated synaptic transmission in pyramidal neurons of the medial prefrontal cortex (mPFC). While HET mice exhibit normal learning and memory, they show defective social behavior and elevated anxiety. Knockdown of Eef2 in excitatory neurons of the mPFC specifically is sufficient to impair social novelty preference. Either chemogenetic activation of excitatory neurons in the mPFC or mPFC local infusion of the AMPAR potentiator PF-4778574 corrects the social novelty deficit of HET mice. Collectively, we identify a novel role for eEF2 in promoting prefrontal AMPAR-mediated synaptic transmission underlying social novelty behavior.
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Affiliation(s)
- Xuanyue Ma
- JNU‐HKUST Joint Laboratory for Neuroscience and Innovative Drug Research, College of PharmacyJinan UniversityGuangzhouChina
| | - Liuren Li
- JNU‐HKUST Joint Laboratory for Neuroscience and Innovative Drug Research, College of PharmacyJinan UniversityGuangzhouChina
| | - Ziming Li
- Guangdong Province Key Laboratory of Brain Function and Disease, Zhongshan School of MedicineSun Yat‐sen UniversityGuangzhouChina
| | - Zhengyi Huang
- JNU‐HKUST Joint Laboratory for Neuroscience and Innovative Drug Research, College of PharmacyJinan UniversityGuangzhouChina
| | - Yaorong Yang
- JNU‐HKUST Joint Laboratory for Neuroscience and Innovative Drug Research, College of PharmacyJinan UniversityGuangzhouChina
| | - Peng Liu
- JNU‐HKUST Joint Laboratory for Neuroscience and Innovative Drug Research, College of PharmacyJinan UniversityGuangzhouChina
| | - Daji Guo
- JNU‐HKUST Joint Laboratory for Neuroscience and Innovative Drug Research, College of PharmacyJinan UniversityGuangzhouChina
- Clinical Neuroscience InstituteThe First Affiliated Hospital of Jinan UniversityGuangzhouChina
| | - Yueyao Li
- JNU‐HKUST Joint Laboratory for Neuroscience and Innovative Drug Research, College of PharmacyJinan UniversityGuangzhouChina
| | - Tianying Wu
- JNU‐HKUST Joint Laboratory for Neuroscience and Innovative Drug Research, College of PharmacyJinan UniversityGuangzhouChina
| | - Ruixiang Luo
- JNU‐HKUST Joint Laboratory for Neuroscience and Innovative Drug Research, College of PharmacyJinan UniversityGuangzhouChina
| | - Junyu Xu
- Department of Neurobiology and Department of Rehabilitation of the Children's HospitalZhejiang University School of MedicineHangzhouChina
| | - Wen‐Cai Ye
- JNU‐HKUST Joint Laboratory for Neuroscience and Innovative Drug Research, College of PharmacyJinan UniversityGuangzhouChina
- Center for Bioactive Natural Molecules and Innovative Drugs Research, College of PharmacyJinan UniversityGuangzhouChina
- Guangdong Province Key Laboratory of Pharmacodynamic Constituents of TCM and New Drugs Research, College of PharmacyJinan UniversityGuangzhouChina
| | - Bin Jiang
- Guangdong Province Key Laboratory of Brain Function and Disease, Zhongshan School of MedicineSun Yat‐sen UniversityGuangzhouChina
| | - Lei Shi
- JNU‐HKUST Joint Laboratory for Neuroscience and Innovative Drug Research, College of PharmacyJinan UniversityGuangzhouChina
- Center for Bioactive Natural Molecules and Innovative Drugs Research, College of PharmacyJinan UniversityGuangzhouChina
- Guangdong Province Key Laboratory of Pharmacodynamic Constituents of TCM and New Drugs Research, College of PharmacyJinan UniversityGuangzhouChina
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27
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Di Domenico F, Lanzillotta C. The disturbance of protein synthesis/degradation homeostasis is a common trait of age-related neurodegenerative disorders. ADVANCES IN PROTEIN CHEMISTRY AND STRUCTURAL BIOLOGY 2022; 132:49-87. [PMID: 36088079 DOI: 10.1016/bs.apcsb.2022.05.008] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Protein homeostasis or "proteostasis" represent the process that regulates the balance of the intracellular functional and "healthy" proteins. Proteostasis is fundamental to preserve physiological metabolic processes in the cell and it allow to respond to any given stimulus as the expression of components of the proteostasis network is customized according to the proteomic demands of different cellular environments. In conditions that promote unfolding/misfolding of proteins chaperones act as signaling molecules inducing extreme measures to either fix the problem or destroy unfolded proteins. When the chaperone machinery fails under pathological insults unfolded proteins induce the endoplasmic reticulum (ER) stress activating the unfolded protein response (UPR) machinery. The activation of the UPR restores ER proteostasis primarily through the transcriptional remodeling of ER protein folding, trafficking, and degradation pathways, such as the ubiquitin proteasome system (UPS). If these mechanisms do not manage to clear the aberrant proteins, proteasome overload and become defective, and misfolded proteins may form aggregates thus extending the UPR mechanism. These aggregates are then attempted to be cleared by macroautophagy. Impaired proteostasis promote the accumulation of misfolded proteins that exacerbate the damage to chaperones, surveillance systems and/or degradative activities. Remarkably, the removal of toxic misfolded proteins is critical for all cells, but it is especially significant in neurons since these cannot be readily replaced. In neurons, the maintenance of efficient proteostasis is essential to healthy aging since the dysregulation of the proteostasis network can lead to neurodegenerative disease. Each of these brain pathologies is characterized by the repeated misfolding of one of more peculiar proteins, which evade both the protein folding machinery and cellular degradation mechanisms and begins to form aggregates that nucleate out into large fibrillar aggregates. In this chapter we describe the mechanisms, associated with faulty proteostasis, that promote the formation of protein aggregates, amyloid fibrils, intracellular, and extracellular inclusions in the most common nondegenerative disorders also referred to as protein misfolding disorders.
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Affiliation(s)
- Fabio Di Domenico
- Department of Biochemical Sciences "A. Rossi Fanelli", Sapienza University of Rome, Rome, Italy.
| | - Chiara Lanzillotta
- Department of Biochemical Sciences "A. Rossi Fanelli", Sapienza University of Rome, Rome, Italy
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28
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Drongitis D, Caterino M, Verrillo L, Santonicola P, Costanzo M, Poeta L, Attianese B, Barra A, Terrone G, Lioi MB, Paladino S, Di Schiavi E, Costa V, Ruoppolo M, Miano MG. Deregulation of microtubule organization and RNA metabolism in Arx models for lissencephaly and developmental epileptic encephalopathy. Hum Mol Genet 2022; 31:1884-1908. [PMID: 35094084 PMCID: PMC9169459 DOI: 10.1093/hmg/ddac028] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2021] [Revised: 01/10/2022] [Accepted: 01/26/2022] [Indexed: 11/18/2022] Open
Abstract
X-linked lissencephaly with abnormal genitalia (XLAG) and developmental epileptic encephalopathy-1 (DEE1) are caused by mutations in the Aristaless-related homeobox (ARX) gene, which encodes a transcription factor responsible for brain development. It has been unknown whether the phenotypically diverse XLAG and DEE1 phenotypes may converge on shared pathways. To address this question, a label-free quantitative proteomic approach was applied to the neonatal brain of Arx knockout (ArxKO/Y) and knock-in polyalanine (Arx(GCG)7/Y) mice that are respectively models for XLAG and DEE1. Gene ontology and protein-protein interaction analysis revealed that cytoskeleton, protein synthesis and splicing control are deregulated in an allelic-dependent manner. Decreased α-tubulin content was observed both in Arx mice and Arx/alr-1(KO) Caenorhabditis elegans ,and a disorganized neurite network in murine primary neurons was consistent with an allelic-dependent secondary tubulinopathy. As distinct features of Arx(GCG)7/Y mice, we detected eIF4A2 overexpression and translational suppression in cortex and primary neurons. Allelic-dependent differences were also established in alternative splicing (AS) regulated by PUF60 and SAM68. Abnormal AS repertoires in Neurexin-1, a gene encoding multiple pre-synaptic organizers implicated in synaptic remodelling, were detected in Arx/alr-1(KO) animals and in Arx(GCG)7/Y epileptogenic brain areas and depolarized cortical neurons. Consistent with a conserved role of ARX in modulating AS, we propose that the allelic-dependent secondary synaptopathy results from an aberrant Neurexin-1 repertoire. Overall, our data reveal alterations mirroring the overlapping and variant effects caused by null and polyalanine expanded mutations in ARX. The identification of these effects can aid in the design of pathway-guided therapy for ARX endophenotypes and NDDs with overlapping comorbidities.
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Affiliation(s)
- Denise Drongitis
- Institute of Genetics and Biophysics ``Adriano Buzzati-Traverso'', National Research Council of Italy, 80131, Naples, Italy
| | - Marianna Caterino
- Department of Molecular Medicine and Medical Biotechnology, University of Naples “Federico II”, 80131 Naples, Italy
- CEINGE - Biotecnologie Avanzate s.c.a.r.l., 80145 Naples, Italy
| | - Lucia Verrillo
- Institute of Genetics and Biophysics ``Adriano Buzzati-Traverso'', National Research Council of Italy, 80131, Naples, Italy
| | - Pamela Santonicola
- Institute of Biosciences and BioResources, National Research Council of Italy, 80131, Naples, Italy
| | - Michele Costanzo
- Department of Molecular Medicine and Medical Biotechnology, University of Naples “Federico II”, 80131 Naples, Italy
- CEINGE - Biotecnologie Avanzate s.c.a.r.l., 80145 Naples, Italy
| | - Loredana Poeta
- Institute of Genetics and Biophysics ``Adriano Buzzati-Traverso'', National Research Council of Italy, 80131, Naples, Italy
- Department of Science, University of Basilicata, 85100 Potenza, Italy
| | - Benedetta Attianese
- Institute of Genetics and Biophysics ``Adriano Buzzati-Traverso'', National Research Council of Italy, 80131, Naples, Italy
| | - Adriano Barra
- Institute of Genetics and Biophysics ``Adriano Buzzati-Traverso'', National Research Council of Italy, 80131, Naples, Italy
| | - Gaetano Terrone
- Department of Translational Medicine, Child Neurology Unit, University of Naples “Federico II”, 80131 Naples, Italy
| | | | - Simona Paladino
- Department of Molecular Medicine and Medical Biotechnology, University of Naples “Federico II”, 80131 Naples, Italy
| | - Elia Di Schiavi
- Institute of Biosciences and BioResources, National Research Council of Italy, 80131, Naples, Italy
| | - Valerio Costa
- Institute of Genetics and Biophysics ``Adriano Buzzati-Traverso'', National Research Council of Italy, 80131, Naples, Italy
| | - Margherita Ruoppolo
- Department of Molecular Medicine and Medical Biotechnology, University of Naples “Federico II”, 80131 Naples, Italy
- CEINGE - Biotecnologie Avanzate s.c.a.r.l., 80145 Naples, Italy
| | - Maria Giuseppina Miano
- Institute of Genetics and Biophysics ``Adriano Buzzati-Traverso'', National Research Council of Italy, 80131, Naples, Italy
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29
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Emerging roles of endoplasmic reticulum proteostasis in brain development. Cells Dev 2022; 170:203781. [DOI: 10.1016/j.cdev.2022.203781] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2021] [Revised: 04/12/2022] [Accepted: 04/20/2022] [Indexed: 11/21/2022]
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30
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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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31
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Altas B, Romanowski AJ, Bunce GW, Poulopoulos A. Neuronal mTOR Outposts: Implications for Translation, Signaling, and Plasticity. Front Cell Neurosci 2022; 16:853634. [PMID: 35465614 PMCID: PMC9021820 DOI: 10.3389/fncel.2022.853634] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2022] [Accepted: 03/04/2022] [Indexed: 11/13/2022] Open
Abstract
The kinase mTOR is a signaling hub for pathways that regulate cellular growth. In neurons, the subcellular localization of mTOR takes on increased significance. Here, we review findings on the localization of mTOR in axons and offer a perspective on how these may impact our understanding of nervous system development, function, and disease. We propose a model where mTOR accumulates in local foci we term mTOR outposts, which can be found in processes distant from a neuron’s cell body. In this model, pathways that funnel through mTOR are gated by local outposts to spatially select and amplify local signaling. The presence or absence of mTOR outposts in a segment of axon or dendrite may determine whether regional mTOR-dependent signals, such as nutrient and growth factor signaling, register toward neuron-wide responses. In this perspective, we present the emerging evidence for mTOR outposts in neurons, their putative roles as spatial gatekeepers of signaling inputs, and the implications of the mTOR outpost model for neuronal protein synthesis, signal transduction, and synaptic plasticity.
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32
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Inhibition of the ISR abrogates mGluR5-dependent long-term depression and spatial memory deficits in a rat model of Alzheimer's disease. Transl Psychiatry 2022; 12:96. [PMID: 35260557 PMCID: PMC8904583 DOI: 10.1038/s41398-022-01862-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/05/2021] [Revised: 02/18/2022] [Accepted: 02/18/2022] [Indexed: 12/13/2022] Open
Abstract
Soluble amyloid-β-protein (Aβ) oligomers, a major hallmark of AD, trigger the integrated stress response (ISR) via multiple pathologies including neuronal hyperactivation, microvascular hypoxia, and neuroinflammation. Increasing eIF2α phosphorylation, the core event of ISR, facilitates metabotropic glutamate receptor (mGluR)-dependent long-term depression (LTD), and suppressing its phosphorylation has the opposite effect. Having found the facilitation of mGluR5-LTD by Aβ in live rats, we wondered if suppressing eIF2α phosphorylation cascade would protect against the synaptic plasticity and cognitive disrupting effects of Aβ. We demonstrate here that the facilitation of mGluR5-LTD in a delayed rat model by single i.c.v. injection of synthetic Aβ1-42. Systemic administration of the small-molecule inhibitor of the ISR called ISRIB (trans-isomer) prevents Aβ-facilitated LTD and abrogates spatial learning and memory deficits in the hippocampus in exogenous synthetic Aβ-injected rats. Moreover, ex vivo evidence indicates that ISRIB normalizes protein synthesis in the hippocampus. Targeting the ISR by suppressing the eIF2α phosphorylation cascade with the eIF2B activator ISRIB may provide protective effects against the synaptic and cognitive disruptive effects of Aβ which likely mediate the early stage of sporadic AD.
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33
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A critical period of translational control during brain development at codon resolution. Nat Struct Mol Biol 2022; 29:1277-1290. [PMID: 36482253 PMCID: PMC9758057 DOI: 10.1038/s41594-022-00882-9] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2021] [Accepted: 10/19/2022] [Indexed: 12/13/2022]
Abstract
Translation modulates the timing and amplification of gene expression after transcription. Brain development requires uniquely complex gene expression patterns, but large-scale measurements of translation directly in the prenatal brain are lacking. We measure the reactants, synthesis and products of mRNA translation spanning mouse neocortex neurogenesis, and discover a transient window of dynamic regulation at mid-gestation. Timed translation upregulation of chromatin-binding proteins like Satb2, which is essential for neuronal subtype differentiation, restricts protein expression in neuronal lineages despite broad transcriptional priming in progenitors. In contrast, translation downregulation of ribosomal proteins sharply decreases ribosome biogenesis, coinciding with a major shift in protein synthesis dynamics at mid-gestation. Changing activity of eIF4EBP1, a direct inhibitor of ribosome biogenesis, is concurrent with ribosome downregulation and affects neurogenesis of the Satb2 lineage. Thus, the molecular logic of brain development includes the refinement of transcriptional programs by translation. Modeling of the developmental neocortex translatome is provided as an open-source searchable resource at https://shiny.mdc-berlin.de/cortexomics .
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34
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Wang DO. Epitranscriptomic regulation of cognitive development and decline. Semin Cell Dev Biol 2021; 129:3-13. [PMID: 34857470 DOI: 10.1016/j.semcdb.2021.11.019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2021] [Revised: 11/16/2021] [Accepted: 11/19/2021] [Indexed: 11/24/2022]
Abstract
Functional genomics and systems biology have opened new doors to previously inaccessible genomic information and holistic approaches to study complex networks of genes and proteins in the central nervous system. The advances are revolutionizing our understanding of the genetic underpinning of cognitive development and decline by facilitating identifications of novel molecular regulators and physiological pathways underlying brain function, and by associating polymorphism and mutations to cognitive dysfunction and neurological diseases. However, our current understanding of these complex gene regulatory mechanisms has yet lacked sufficient mechanistic resolution for further translational breakthroughs. Here we review recent findings from the burgeoning field of epitranscriptomics in association of cognitive functions with a special focus on the epitranscritomic regulation in subcellular locations such as chromosome, synapse, and mitochondria. Although there are important gaps in knowledge, current evidence is suggesting that this layer of RNA regulation may be of particular interest for the spatiotemporally coordinated regulation of gene networks in developing and maintaining brain function that underlie cognitive changes.
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Affiliation(s)
- Dan Ohtan Wang
- Center for Biosystems Dynamics Research, RIKEN, 2-2-3 Minatojima-minamimachi, Chuo-ku, Kobe, Hyogo 650-0047, Japan; Graduate School of Biostudies, Kyoto University, Yoshida Hon-machi, Kyoto 606-8501, Japan.
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35
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Ma T. Roles of eukaryotic elongation factor 2 kinase (eEF2K) in neuronal plasticity, cognition, and Alzheimer disease. J Neurochem 2021. [PMID: 34796967 DOI: 10.1111/jnc.15541] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2021] [Revised: 10/19/2021] [Accepted: 11/15/2021] [Indexed: 01/04/2023]
Abstract
Understanding the molecular signaling mechanisms underlying cognition and neuronal plasticity would provide insights into the pathogenesis of neuronal disorders characterized by cognitive syndromes such as Alzheimer disease (AD). Phosphorylation of the mRNA translational factor eukaryotic elongation factor 2 (eEF2) by its specific kinase eEF2K is critically involved in protein synthesis regulation. In this review, we discussed recent studies on the roles of eEF2K/eEF2 signaling in the context of regulation/dysregulation of cognitive function and synaptic plasticity. We specifically focus on the discussion of recent evidence indicating suppression of eEF2K signaling as a potential novel therapeutic avenue for AD and related dementias (ADRDs).
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Affiliation(s)
- Tao Ma
- Department of Internal Medicine-Gerontology and Geriatric Medicine, Wake Forest University School of Medicine, Winston-Salem, North Carolina, USA.,Department of Physiology and Pharmacology, Wake Forest University School of Medicine, Winston-Salem, North Carolina, USA.,Department of Neurobiology and Anatomy, Wake Forest University School of Medicine, Winston-Salem, North Carolina, USA
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36
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Conde-Dusman MJ, Dey PN, Elía-Zudaire Ó, Rabaneda LG, García-Lira C, Grand T, Briz V, Velasco ER, Andero R, Niñerola S, Barco A, Paoletti P, Wesseling JF, Gardoni F, Tavalin SJ, Perez-Otaño I. Control of protein synthesis and memory by GluN3A-NMDA receptors through inhibition of GIT1/mTORC1 assembly. eLife 2021; 10:e71575. [PMID: 34787081 PMCID: PMC8598234 DOI: 10.7554/elife.71575] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2021] [Accepted: 10/13/2021] [Indexed: 12/03/2022] Open
Abstract
De novo protein synthesis is required for synapse modifications underlying stable memory encoding. Yet neurons are highly compartmentalized cells and how protein synthesis can be regulated at the synapse level is unknown. Here, we characterize neuronal signaling complexes formed by the postsynaptic scaffold GIT1, the mechanistic target of rapamycin (mTOR) kinase, and Raptor that couple synaptic stimuli to mTOR-dependent protein synthesis; and identify NMDA receptors containing GluN3A subunits as key negative regulators of GIT1 binding to mTOR. Disruption of GIT1/mTOR complexes by enhancing GluN3A expression or silencing GIT1 inhibits synaptic mTOR activation and restricts the mTOR-dependent translation of specific activity-regulated mRNAs. Conversely, GluN3A removal enables complex formation, potentiates mTOR-dependent protein synthesis, and facilitates the consolidation of associative and spatial memories in mice. The memory enhancement becomes evident with light or spaced training, can be achieved by selectively deleting GluN3A from excitatory neurons during adulthood, and does not compromise other aspects of cognition such as memory flexibility or extinction. Our findings provide mechanistic insight into synaptic translational control and reveal a potentially selective target for cognitive enhancement.
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Affiliation(s)
- María J Conde-Dusman
- lnstituto de Neurociencias (UMH-CSIC)AlicanteSpain
- Centro de Investigación Médica Aplicada (CIMA), University of NavarraPamplonaSpain
- Centre for Developmental Neurobiology, Institute of Psychiatry, King’s College LondonLondonUnited Kingdom
| | - Partha N Dey
- Centro de Investigación Médica Aplicada (CIMA), University of NavarraPamplonaSpain
- National Eye Institute, National Institutes of HealthBethesdaUnited States
| | | | - Luis G Rabaneda
- lnstituto de Neurociencias (UMH-CSIC)AlicanteSpain
- Centro de Investigación Médica Aplicada (CIMA), University of NavarraPamplonaSpain
- Institute of Science and Technology AustriaKlosterneuburgAustria
| | | | - Teddy Grand
- Institut de Biologie de l’Ecole Normale Supérieure/CNRS/INSERMParisFrance
| | - Victor Briz
- Centro de Biología Molecular Severo Ochoa (UAM-CSIC)MadridSpain
| | - Eric R Velasco
- Institut de Neurociències, Universitat Autònoma de BarcelonaBellaterraSpain
| | - Raül Andero
- Institut de Neurociències, Departament de Psicobiologia i de Metodologia de les Ciències de la Salut, Unitat de Neurociència Traslacional, Parc Taulí Hospital Universitari, Institut d’Investigació i Innovació Parc Taulí (I3PT), Universitat Autònoma de BarcelonaBellaterraSpain
- Centro de Investigación Biomédica en Red de Salud Mental (CIBERSAM), Instituto de Salud Carlos IIIMadridSpain
- ICREABarcelonaSpain
| | | | - Angel Barco
- lnstituto de Neurociencias (UMH-CSIC)AlicanteSpain
| | - Pierre Paoletti
- Institut de Biologie de l’Ecole Normale Supérieure/CNRS/INSERMParisFrance
| | | | - Fabrizio Gardoni
- Department of Pharmacological and Biomolecular Sciences, University of MilanMilanItaly
| | - Steven J Tavalin
- Department of Pharmacology, Addiction Science, and Toxicology, University of Tennessee Health Science CenterMemphisUnited States
| | - Isabel Perez-Otaño
- lnstituto de Neurociencias (UMH-CSIC)AlicanteSpain
- Centro de Investigación Médica Aplicada (CIMA), University of NavarraPamplonaSpain
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37
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Comparative ribosome profiling reveals distinct translational landscapes of salt-sensitive and -tolerant rice. BMC Genomics 2021; 22:612. [PMID: 34384368 PMCID: PMC8359061 DOI: 10.1186/s12864-021-07922-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2020] [Accepted: 08/03/2021] [Indexed: 01/27/2023] Open
Abstract
BACKGROUND Soil salinization represents a serious threat to global rice production. Although significant research has been conducted to understand salt stress at the genomic, transcriptomic and proteomic levels, few studies have focused on the translatomic responses to this stress. Recent studies have suggested that transcriptional and translational responses to salt stress can often operate independently. RESULTS We sequenced RNA and ribosome-protected fragments (RPFs) from the salt-sensitive rice (O. sativa L.) cultivar 'Nipponbare' (NB) and the salt-tolerant cultivar 'Sea Rice 86' (SR86) under normal and salt stress conditions. A large discordance between salt-induced transcriptomic and translatomic alterations was found in both cultivars, with more translationally regulated genes being observed in SR86 in comparison to NB. A biased ribosome occupancy, wherein RPF depth gradually increased from the 5' ends to the 3' ends of coding regions, was revealed in NB and SR86. This pattern was strengthened by salt stress, particularly in SR86. On the contrary, the strength of ribosome stalling was accelerated in salt-stressed NB but decreased in SR86. CONCLUSIONS This study revealed that translational reprogramming represents an important layer of salt stress responses in rice, and the salt-tolerant cultivar SR86 adopts a more flexible translationally adaptive strategy to cope with salt stress compared to the salt susceptible cultivar NB. The differences in translational dynamics between NB and SR86 may derive from their differing levels of ribosome stalling under salt stress.
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38
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Mendoza MB, Gutierrez S, Ortiz R, Moreno DF, Dermit M, Dodel M, Rebollo E, Bosch M, Mardakheh FK, Gallego C. The elongation factor eEF1A2 controls translation and actin dynamics in dendritic spines. Sci Signal 2021; 14:14/691/eabf5594. [PMID: 34257105 DOI: 10.1126/scisignal.abf5594] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Synaptic plasticity involves structural modifications in dendritic spines that are modulated by local protein synthesis and actin remodeling. Here, we investigated the molecular mechanisms that connect synaptic stimulation to these processes. We found that the phosphorylation of isoform-specific sites in eEF1A2-an essential translation elongation factor in neurons-is a key modulator of structural plasticity in dendritic spines. Expression of a nonphosphorylatable eEF1A2 mutant stimulated mRNA translation but reduced actin dynamics and spine density. By contrast, a phosphomimetic eEF1A2 mutant exhibited decreased association with F-actin and was inactive as a translation elongation factor. Activation of metabotropic glutamate receptor signaling triggered transient dissociation of eEF1A2 from its regulatory guanine exchange factor (GEF) protein in dendritic spines in a phosphorylation-dependent manner. We propose that eEF1A2 establishes a cross-talk mechanism that coordinates translation and actin dynamics during spine remodeling.
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Affiliation(s)
- Mònica B Mendoza
- Molecular Biology Institute of Barcelona (IBMB), CSIC, Catalonia 08028, Spain
| | - Sara Gutierrez
- Molecular Biology Institute of Barcelona (IBMB), CSIC, Catalonia 08028, Spain
| | - Raúl Ortiz
- Molecular Biology Institute of Barcelona (IBMB), CSIC, Catalonia 08028, Spain
| | - David F Moreno
- Molecular Biology Institute of Barcelona (IBMB), CSIC, Catalonia 08028, Spain
| | - Maria Dermit
- Centre for Cancer Cell and Molecular Biology, Barts Cancer Institute, Queen Mary University of London, Charterhouse square, London EC1M 6BQ, UK
| | - Martin Dodel
- Centre for Cancer Cell and Molecular Biology, Barts Cancer Institute, Queen Mary University of London, Charterhouse square, London EC1M 6BQ, UK
| | - Elena Rebollo
- Molecular Biology Institute of Barcelona (IBMB), CSIC, Catalonia 08028, Spain
| | - Miquel Bosch
- Department of Basic Sciences, Universitat Internacional de Catalunya (UIC-Barcelona), Sant Cugat del Vallès 08195, Spain.,Institute for Bioengineering of Catalonia (IBEC), The Barcelona Institute of Science and Technology (BIST), Barcelona 08028, Spain
| | - Faraz K Mardakheh
- Centre for Cancer Cell and Molecular Biology, Barts Cancer Institute, Queen Mary University of London, Charterhouse square, London EC1M 6BQ, UK
| | - Carme Gallego
- Molecular Biology Institute of Barcelona (IBMB), CSIC, Catalonia 08028, Spain.
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Pandey K, Yu XW, Steinmetz A, Alberini CM. Autophagy coupled to translation is required for long-term memory. Autophagy 2021; 17:1614-1635. [PMID: 32501746 PMCID: PMC8354608 DOI: 10.1080/15548627.2020.1775393] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2019] [Revised: 05/12/2020] [Accepted: 05/22/2020] [Indexed: 02/07/2023] Open
Abstract
An increase in protein synthesis following learning is a fundamental and evolutionarily conserved mechanism of long-term memory. To maintain homeostasis, this protein synthesis must be counterbalanced by mechanisms such as protein degradation. Recent studies reported that macroautophagy/autophagy, a major protein degradation mechanism, is required for long-term memory formation. However, how learning regulates autophagy and recruits it into long-term memory formation remains to be established. Here, we show that inhibitory avoidance in rats significantly increases the levels of autophagy and lysosomal degradation proteins, including BECN1/beclin 1, LC3-II, SQSTM1/p62 and LAMP1, as well as autophagic flux in the hippocampus. Moreover, pharmacological inhibition or targeted molecular disruption of the learning-induced autophagy impairs long-term memory, leaving short-term memory intact. The increase in autophagy proteins results from active translation of their mRNA and not from changes in their total mRNA levels. Additionally, the induction of autophagy requires the immediate early gene Arc/Arg3.1. Finally, in contrast to classical regulation of autophagy in other systems, we found that the increase in autophagy upon learning is dispensable for the increase in protein synthesis. We conclude that coupling between learning-induced translation and autophagy, rather than translation per se, is an essential mechanism of long-term memory.Abbreviations: AAV: adeno-associated virus; ARC/ARG3.1: activity regulated cytoskeletal-associated protein; ATG: autophagy related; DG: dentate gyrus; GFP: green fluorescent protein; IA: inhibitory avoidance; LAMP1: lysosomal-associated membrane protein 1; MAP1LC3B/LC3B: microtubule-associated protein 1 light chain 3 beta; ODN: oligodeoxynucleotide; qPCR: quantitative polymerase chain reaction; SBI: SBI0206965; SQSTM1/p62: sequestosome 1; SUnSET: surface sensing of translation; TRAP: translating ribosome affinity purification; ULK1: unc-51 like kinase 1.
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Affiliation(s)
- Kiran Pandey
- Center for Neural Science, New York University, New York, NY, USA
| | - Xiao-Wen Yu
- Center for Neural Science, New York University, New York, NY, USA
| | - Adam Steinmetz
- Center for Neural Science, New York University, New York, NY, USA
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40
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Reconsolidation of a post-ingestive nutrient memory requires mTOR in the central amygdala. Mol Psychiatry 2021; 26:2820-2836. [PMID: 32873898 DOI: 10.1038/s41380-020-00874-5] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/10/2020] [Revised: 08/04/2020] [Accepted: 08/21/2020] [Indexed: 01/22/2023]
Abstract
The central control of feeding behavior and metabolic homeostasis has been proposed to involve a form of post-ingestive nutrient learning independent of the gustatory value of food. However, after such learning, it is unknown which brain regions or circuits are activated to retrieve the stored memory and whether this memory undergoes reconsolidation that depends on protein synthesis after its reactivation through retrieval. In the present study, using a conditioned-flavor-preference paradigm by associating flavors with intra-gastric infusion of glucose to minimize the evaluation of the taste of food, we show that retrieval of the post-ingestive nutrient-conditioned flavor memory stimulates multiple brain regions in mice, including the central nucleus of the amygdala (CeA). Moreover, memory retrieval activated the mammalian target of rapamycin complex 1 (mTORC1) in the CeA, while site-specific or systemic inhibition of mTORC1 immediately after retrieval prevented the subsequent expression of the post-ingestive nutrient-associated flavor memory, leading to a long-lasting suppression of reinstatement. Taken together, our findings suggest that the reconsolidation process of a post-ingestive nutrient memory modulates food preferences.
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41
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Lee S, Kang H, Jung H, Kim E, Lee E. Gene Dosage- and Age-Dependent Differential Transcriptomic Changes in the Prefrontal Cortex of Shank2-Mutant Mice. Front Mol Neurosci 2021; 14:683196. [PMID: 34177464 PMCID: PMC8226033 DOI: 10.3389/fnmol.2021.683196] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2021] [Accepted: 05/18/2021] [Indexed: 11/20/2022] Open
Abstract
Shank2 is an abundant postsynaptic scaffolding protein that is known to regulate excitatory synapse assembly and synaptic transmission and has been implicated in various neurodevelopmental disorders, including autism spectrum disorders (ASD). Previous studies on Shank2-mutant mice provided mechanistic insights into their autistic-like phenotypes, but it remains unclear how transcriptomic patterns are changed in brain regions of the mutant mice in age- and gene dosage-dependent manners. To this end, we performed RNA-Seq analyses of the transcripts from the prefrontal cortex (PFC) of heterozygous and homozygous Shank2-mutant mice lacking exons 6 and 7 at juvenile (week 3) and adult (week 12) stages. Juvenile heterozygous Shank2-mutant mice showed upregulation of glutamate synapse-related genes, downregulation of ribosomal and mitochondrial genes, and transcriptomic changes that are opposite to those observed in ASD (anti-ASD) such as upregulation of ASD_down (downregulated in ASD), GABA neuron-related, and oligodendrocyte-related genes. Juvenile homozygous Shank2 mice showed upregulation of chromatin-related genes and transcriptomic changes that are in line with those occurring in ASD (pro-ASD) such as downregulation of ASD_down, GABA neuron-related, and oligodendrocyte-related genes. Adult heterozygous and homozygous Shank2-mutant mice both exhibited downregulation of ribosomal and mitochondrial genes and pro-ASD transcriptomic changes. Therefore, the gene dosage- and age-dependent effects of Shank2 deletions in mice include differential transcriptomic changes across distinct functional contexts, including synapses, chromatin, ribosomes, mitochondria, GABA neurons, and oligodendrocytes.
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Affiliation(s)
- Seungjoon Lee
- Department of Biological Sciences, Korea Advanced Institute for Science and Technology (KAIST), Daejeon, South Korea
| | - Hyojin Kang
- Division of National Supercomputing, KISTI, Daejeon, South Korea
| | - Hwajin Jung
- Center for Synaptic Brain Dysfunctions, Institute for Basic Science (IBS), Daejeon, South Korea
| | - Eunjoon Kim
- Department of Biological Sciences, Korea Advanced Institute for Science and Technology (KAIST), Daejeon, South Korea.,Center for Synaptic Brain Dysfunctions, Institute for Basic Science (IBS), Daejeon, South Korea
| | - Eunee Lee
- Center for Synaptic Brain Dysfunctions, Institute for Basic Science (IBS), Daejeon, South Korea.,Department of Anatomy, School of Medicine, Yonsei University, Seoul, South Korea
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42
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Sossin WS, Anadolu MN, Langille JJ. Neuroscience: A New Pathway to Make Us Smarter and Happier. Curr Biol 2021; 30:R1051-R1054. [PMID: 32961162 DOI: 10.1016/j.cub.2020.07.018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Treatments that improve cognition and decrease depression converge on decreasing phosphorylation of eukaryotic elongation factor 2 (eEF2). This decrease is sufficient to lead to altered levels of proteins that cause an increase in new neurons, improved cognition and less depression.
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Affiliation(s)
- Wayne S Sossin
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, QC H3A 2B4, Canada.
| | - Mina N Anadolu
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, QC H3A 2B4, Canada
| | - Jesse J Langille
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, QC H3A 2B4, Canada
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4E-BP2-dependent translation in parvalbumin neurons controls epileptic seizure threshold. Proc Natl Acad Sci U S A 2021; 118:2025522118. [PMID: 33876772 DOI: 10.1073/pnas.2025522118] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The mechanistic/mammalian target of rapamycin complex 1 (mTORC1) integrates multiple signals to regulate critical cellular processes such as mRNA translation, lipid biogenesis, and autophagy. Germline and somatic mutations in mTOR and genes upstream of mTORC1, such as PTEN, TSC1/2, AKT3, PIK3CA, and components of GATOR1 and KICSTOR complexes, are associated with various epileptic disorders. Increased mTORC1 activity is linked to the pathophysiology of epilepsy in both humans and animal models, and mTORC1 inhibition suppresses epileptogenesis in humans with tuberous sclerosis and animal models with elevated mTORC1 activity. However, the role of mTORC1-dependent translation and the neuronal cell types mediating the effect of enhanced mTORC1 activity in seizures remain unknown. The eukaryotic translation initiation factor 4E-binding protein 1 (4E-BP1) and 2 (4E-BP2) are translational repressors downstream of mTORC1. Here we show that the ablation of 4E-BP2, but not 4E-BP1, in mice increases the sensitivity to pentylenetetrazole (PTZ)- and kainic acid (KA)-induced seizures. We demonstrate that the deletion of 4E-BP2 in inhibitory, but not excitatory neurons, causes an increase in the susceptibility to PTZ-induced seizures. Moreover, mice lacking 4E-BP2 in parvalbumin, but not somatostatin or VIP inhibitory neurons exhibit a lowered threshold for seizure induction and reduced number of parvalbumin neurons. A mouse model harboring a human PIK3CA mutation that enhances the activity of the PI3K-AKT pathway (Pik3ca H1047R-Pvalb ) selectively in parvalbumin neurons shows susceptibility to PTZ-induced seizures. Our data identify 4E-BP2 as a regulator of epileptogenesis and highlight the central role of increased mTORC1-dependent translation in parvalbumin neurons in the pathophysiology of epilepsy.
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Hetz C. Adapting the proteostasis capacity to sustain brain healthspan. Cell 2021; 184:1545-1560. [PMID: 33691137 DOI: 10.1016/j.cell.2021.02.007] [Citation(s) in RCA: 61] [Impact Index Per Article: 20.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2020] [Revised: 01/20/2021] [Accepted: 02/01/2021] [Indexed: 12/13/2022]
Abstract
Sustaining neuronal proteostasis during the course of our life is a central aspect required for brain function. The dynamic nature of synaptic composition and abundance is a requisite to drive cognitive and motor processes involving a tight control of many aspects of protein biosynthesis and degradation. Through the concerted action of specialized stress sensors, the proteostasis network monitors and limits the accumulation of damaged, misfolded, or aggregated proteins. These stress pathways signal to the cytosol and nucleus to reprogram gene expression, enabling adaptive programs to recover cell function. During aging, the activity of the proteostasis network declines, which may increase the risk of accumulating abnormal protein aggregates, a hallmark of most neurodegenerative diseases. Here, I discuss emerging concepts illustrating the functional significance of adaptive signaling pathways to normal brain physiology and their contribution to age-related disorders. Pharmacological and gene therapy strategies to intervene and boost proteostasis are expected to extend brain healthspan and ameliorate disease states.
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Affiliation(s)
- Claudio Hetz
- Biomedical Neuroscience Institute, Faculty of Medicine, University of Chile, Santiago, Chile; Center for Geroscience, Brain Health and Metabolism, Santiago, Chile; Program of Cellular and Molecular Biology, Institute of Biomedical Sciences, University of Chile, Santiago, Chile; Buck Institute for Research on Aging, Novato, CA, USA.
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Houston R, Sekine S, Sekine Y. The coupling of translational control and stress responses. J Biochem 2021; 168:93-102. [PMID: 32484875 DOI: 10.1093/jb/mvaa061] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2020] [Accepted: 05/25/2020] [Indexed: 12/16/2022] Open
Abstract
The translation of messenger RNA (mRNA) into protein is a multistep process by which genetic information transcribed into an mRNA is decoded to produce a specific polypeptide chain of amino acids. Ribosomes play a central role in translation by coordinately working with various translation regulatory factors and aminoacyl-transfer RNAs. Various stresses attenuate the ribosomal synthesis in the nucleolus as well as the translation rate in the cytosol. To efficiently reallocate cellular energy and resources, mammalian cells are endowed with mechanisms that directly link the suppression of translation-related processes to the activation of stress adaptation programmes. This review focuses on the integrated stress response (ISR) and the nucleolar stress response (NSR) both of which are activated by various stressors and selectively upregulate stress-responsive transcription factors. Emerging findings have delineated the detailed molecular mechanisms of the ISR and NSR and expanded their physiological and pathological significances.
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Affiliation(s)
- Ryan Houston
- Aging Institute, Department of Medicine, University of Pittsburgh, 100 Technology Drive, Pittsburgh, PA, 15219 USA
| | - Shiori Sekine
- Aging Institute, Department of Medicine, University of Pittsburgh, 100 Technology Drive, Pittsburgh, PA, 15219 USA.,Division of Cardiology, Department of Medicine, University of Pittsburgh, 3550 Terrace Street, Pittsburgh, PA 15261, USA
| | - Yusuke Sekine
- Aging Institute, Department of Medicine, University of Pittsburgh, 100 Technology Drive, Pittsburgh, PA, 15219 USA.,Division of Endocrinology and Metabolism, Department of Medicine, University of Pittsburgh, 3550 Terrace Street, Pittsburgh, PA 15261, USA
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Li W, Ali T, Zheng C, Liu Z, He K, Shah FA, Ren Q, Rahman SU, Li N, Yu ZJ, Li S. Fluoxetine regulates eEF2 activity (phosphorylation) via HDAC1 inhibitory mechanism in an LPS-induced mouse model of depression. J Neuroinflammation 2021; 18:38. [PMID: 33526073 PMCID: PMC7852137 DOI: 10.1186/s12974-021-02091-5] [Citation(s) in RCA: 53] [Impact Index Per Article: 17.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2020] [Accepted: 01/19/2021] [Indexed: 02/12/2023] Open
Abstract
BACKGROUND Selective serotonin reuptaker inhibitors, including fluoxetine, are widely studied and prescribed antidepressants, while their exact molecular and cellular mechanism are yet to be defined. We investigated the involvement of HDAC1 and eEF2 in the antidepressant mechanisms of fluoxetine using a lipopolysaccharide (LPS)-induced depression-like behavior model. METHODS For in vivo analysis, mice were treated with LPS (2 mg/kg BW), fluoxetine (20 mg/kg BW), HDAC1 activator (Exifone: 54 mg/kg BW) and NH125 (1 mg/kg BW). Depressive-like behaviors were confirmed via behavior tests including OFT, FST, SPT, and TST. Cytokines were measured by ELISA while Iba-1 and GFAP expression were determined by immunofluorescence. Further, the desired gene expression was measured by immunoblotting. For in vitro analysis, BV2 cell lines were cultured; treated with LPS, exifone, and fluoxetine; collected; and analyzed. RESULTS Mice treated with LPS displayed depression-like behaviors, pronounced neuroinflammation, increased HDAC1 expression, and reduced eEF2 activity, as accompanied by altered synaptogenic factors including BDNF, SNAP25, and PSD95. Fluoxetine treatment exhibited antidepressant effects and ameliorated the molecular changes induced by LPS. Exifone, a selective HDAC1 activator, reversed the antidepressant and anti-inflammatory effects of fluoxetine both in vivo and in vitro, supporting a causing role of HDAC1 in neuroinflammation allied depression. Further molecular mechanisms underlying HDAC1 were explored with NH125, an eEF2K inhibitor, whose treatment reduced immobility time, altered pro-inflammatory cytokines, and NLRP3 expression. Moreover, NH125 treatment enhanced eEF2 and GSK3β activities, BDNF, SNAP25, and PSD95 expression, but had no effects on HDAC1. CONCLUSIONS Our results showed that the antidepressant effects of fluoxetine may involve HDAC1-eEF2 related neuroinflammation and synaptogenesis.
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Affiliation(s)
- Weifen Li
- State Key Laboratory of Oncogenomics, School of Chemical Biology and Biotechnology, Peking University Shenzhen Graduate School, Shenzhen, 518055 China
| | - Tahir Ali
- State Key Laboratory of Oncogenomics, School of Chemical Biology and Biotechnology, Peking University Shenzhen Graduate School, Shenzhen, 518055 China
| | - Chengyou Zheng
- State Key Laboratory of Oncogenomics, School of Chemical Biology and Biotechnology, Peking University Shenzhen Graduate School, Shenzhen, 518055 China
| | - Zizhen Liu
- State Key Laboratory of Oncogenomics, School of Chemical Biology and Biotechnology, Peking University Shenzhen Graduate School, Shenzhen, 518055 China
| | - Kaiwu He
- State Key Laboratory of Oncogenomics, School of Chemical Biology and Biotechnology, Peking University Shenzhen Graduate School, Shenzhen, 518055 China
| | - Fawad Ali Shah
- State Key Laboratory of Oncogenomics, School of Chemical Biology and Biotechnology, Peking University Shenzhen Graduate School, Shenzhen, 518055 China
- Riphah Institute of Pharmaceutical Sciences, Riphah International University Islamabad, Islamabad, Pakistan
| | - Qingguo Ren
- Department of Neurology, Affiliated ZhongDa Hospital, School of Medicine, Southeast University, Nanjing, China
| | - Shafiq Ur Rahman
- State Key Laboratory of Oncogenomics, School of Chemical Biology and Biotechnology, Peking University Shenzhen Graduate School, Shenzhen, 518055 China
- Department of Pharmacy, Shaheed Benazir Bhutto University, Sheringal, Dir, 18000, Pakistan
| | - Ningning Li
- Tomas Lindahl Nobel Laureate Laboratory, Precision Medicine Research Centre, The Seventh Affiliated Hospital of Sun Yat-sen University, Shenzhen, 518107 China
| | - Zhi-Jian Yu
- Department of Infectious Diseases and Shenzhen Key Laboratory for Endogenous Infections, The 6th Affiliated Hospital of Shenzhen University Health Science Center, No 89, Taoyuan Road, Nanshan District, Shenzhen, 518052 China
| | - Shupeng Li
- State Key Laboratory of Oncogenomics, School of Chemical Biology and Biotechnology, Peking University Shenzhen Graduate School, Shenzhen, 518055 China
- Campbell Research Institute, Centre for Addiction and Mental Health, Toronto, Ontario Canada
- Department of Psychiatry, University of Toronto, Toronto, Ontario Canada
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Zhang S, Chen Y, Wang Y, Zhang P, Chen G, Zhou Y. Insights Into Translatomics in the Nervous System. Front Genet 2021; 11:599548. [PMID: 33408739 PMCID: PMC7779767 DOI: 10.3389/fgene.2020.599548] [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] [Received: 08/29/2020] [Accepted: 11/30/2020] [Indexed: 12/11/2022] Open
Abstract
Most neurological disorders are caused by abnormal gene translation. Generally, dysregulation of elements involved in the translational process disrupts homeostasis in neurons and neuroglia. Better understanding of how the gene translation process occurs requires detailed analysis of transcriptomic and proteomic profile data. However, a lack of strictly direct correlations between mRNA and protein levels limits translational investigation by combining transcriptomic and proteomic profiling. The much better correlation between proteins and translated mRNAs than total mRNAs in abundance and insufficiently sensitive proteomics approach promote the requirement of advances in translatomics technology. Translatomics which capture and sequence the mRNAs associated with ribosomes has been effective in identifying translational changes by genetics or projections, ribosome stalling, local translation, and transcript isoforms in the nervous system. Here, we place emphasis on the main three translatomics methods currently used to profile mRNAs attached to ribosome-nascent chain complex (RNC-mRNA). Their prominent applications in neurological diseases including glioma, neuropathic pain, depression, fragile X syndrome (FXS), neurodegenerative disorders are outlined. The content reviewed here expands our understanding on the contributions of aberrant translation to neurological disease development.
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Affiliation(s)
- Shuxia Zhang
- Department of Anesthesiology, Sir Run Run Shaw Hospital, School of Medicine, Zhejiang University, Hangzhou, China
| | - Yeru Chen
- Department of Anesthesiology, Sir Run Run Shaw Hospital, School of Medicine, Zhejiang University, Hangzhou, China
| | - Yongjie Wang
- Key Laboratory of Elemene Anti-Cancer Medicine of Zhejiang Province and Holistic Integrative Pharmacy Institutes, Hangzhou Normal University, Hangzhou, China.,Engineering Laboratory of Development and Application of Traditional Chinese Medicine from Zhejiang Province, Holistic Integrative Pharmacy Institutes, Hangzhou Normal University, Hangzhou, China
| | - Piao Zhang
- Department of Anesthesiology, Sir Run Run Shaw Hospital, School of Medicine, Zhejiang University, Hangzhou, China
| | - Gang Chen
- Department of Anesthesiology, Sir Run Run Shaw Hospital, School of Medicine, Zhejiang University, Hangzhou, China
| | - Youfa Zhou
- Department of Anesthesiology, Sir Run Run Shaw Hospital, School of Medicine, Zhejiang University, Hangzhou, China
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Protein Synthesis in the Developing Neocortex at Near-Atomic Resolution Reveals Ebp1-Mediated Neuronal Proteostasis at the 60S Tunnel Exit. Mol Cell 2020; 81:304-322.e16. [PMID: 33357414 DOI: 10.1016/j.molcel.2020.11.037] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2019] [Revised: 09/04/2020] [Accepted: 11/19/2020] [Indexed: 02/07/2023]
Abstract
Protein synthesis must be finely tuned in the developing nervous system as the final essential step of gene expression. This study investigates the architecture of ribosomes from the neocortex during neurogenesis, revealing Ebp1 as a high-occupancy 60S peptide tunnel exit (TE) factor during protein synthesis at near-atomic resolution by cryoelectron microscopy (cryo-EM). Ribosome profiling demonstrated Ebp1-60S binding is highest during start codon initiation and N-terminal peptide elongation, regulating ribosome occupancy of these codons. Membrane-targeting domains emerging from the 60S tunnel, which recruit SRP/Sec61 to the shared binding site, displace Ebp1. Ebp1 is particularly abundant in the early-born neural stem cell (NSC) lineage and regulates neuronal morphology. Ebp1 especially impacts the synthesis of membrane-targeted cell adhesion molecules (CAMs), measured by pulsed stable isotope labeling by amino acids in cell culture (pSILAC)/bioorthogonal noncanonical amino acid tagging (BONCAT) mass spectrometry (MS). Therefore, Ebp1 is a central component of protein synthesis, and the ribosome TE is a focal point of gene expression control in the molecular specification of neuronal morphology during development.
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The eIF4E homolog 4EHP (eIF4E2) regulates hippocampal long-term depression and impacts social behavior. Mol Autism 2020; 11:92. [PMID: 33225984 PMCID: PMC7682028 DOI: 10.1186/s13229-020-00394-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2020] [Accepted: 10/23/2020] [Indexed: 12/27/2022] Open
Abstract
Background The regulation of protein synthesis is a critical step in gene expression, and its dysfunction is implicated in autism spectrum disorder (ASD). The eIF4E homologous protein (4EHP, also termed eIF4E2) binds to the mRNA 5′ cap to repress translation. The stability of 4EHP is maintained through physical interaction with GRB10 interacting GYF protein 2 (GIGYF2). Gene-disruptive mutations in GIGYF2 are linked to ASD, but causality is lacking. We hypothesized that GIGYF2 mutations cause ASD by disrupting 4EHP function. Methods Since homozygous deletion of either gene is lethal, we generated a cell-type-specific knockout model where Eif4e2 (the gene encoding 4EHP) is deleted in excitatory neurons of the forebrain (4EHP-eKO). In this model, we investigated ASD-associated synaptic plasticity dysfunction, ASD-like behaviors, and global translational control. We also utilized mice lacking one copy of Gigyf2, Eif4e2 or co-deletion of one copy of each gene to further investigate ASD-like behaviors. Results 4EHP is expressed in excitatory neurons and synaptosomes, and its amount increases during development. 4EHP-eKO mice display exaggerated mGluR-LTD, a phenotype frequently observed in mouse models of ASD. Consistent with synaptic plasticity dysfunction, the mice displayed social behavior impairments without being confounded by deficits in olfaction, anxiety, locomotion, or motor ability. Repetitive behaviors and vocal communication were not affected by loss of 4EHP in excitatory neurons. Heterozygous deletion of either Gigyf2, Eif4e2, or both genes in mice did not result in ASD-like behaviors (i.e. decreases in social behavior or increases in marble burying). Interestingly, exaggerated mGluR-LTD and impaired social behaviors were not attributed to changes in hippocampal global protein synthesis, which suggests that 4EHP and GIGYF2 regulate the translation of specific mRNAs to mediate these effects. Limitations This study did not identify which genes are translationally regulated by 4EHP and GIGYF2. Identification of mistranslated genes in 4EHP-eKO mice might provide a mechanistic explanation for the observed impairment in social behavior and exaggerated LTD. Future experiments employing affinity purification of translating ribosomes and mRNA sequencing in 4EHP-eKO mice will address this relevant issue. Conclusions Together these results demonstrate an important role of 4EHP in regulating hippocampal plasticity and ASD-associated social behaviors, consistent with the link between mutations in GIGYF2 and ASD.
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Hien A, Molinaro G, Liu B, Huber KM, Richter JD. Ribosome profiling in mouse hippocampus: plasticity-induced regulation and bidirectional control by TSC2 and FMRP. Mol Autism 2020; 11:78. [PMID: 33054857 PMCID: PMC7556950 DOI: 10.1186/s13229-020-00384-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2020] [Accepted: 09/23/2020] [Indexed: 01/09/2023] Open
Abstract
BACKGROUND Mutations in TSC2 are the most common cause of tuberous sclerosis (TSC), a disorder with a high incidence of autism and intellectual disability. TSC2 regulates mRNA translation required for group 1 metabotropic glutamate receptor-dependent synaptic long-term depression (mGluR-LTD) and behavior, but the identity of mRNAs responsive to mGluR-LTD signaling is largely unknown. METHODS We utilized Tsc2+/- mice as a mouse model of TSC and prepared hippocampal slices from these animals. We induced mGluR-LTD synaptic plasticity in slices and processed the samples for RNA-seq and ribosome profiling to identify differentially expressed genes in Tsc2+/- and following mGluR-LTD synaptic plasticity. RESULTS Ribosome profiling reveals that in Tsc2+/- mouse hippocampal slices, the expression of several mRNAs was dysregulated: terminal oligopyrimidine (TOP)-containing mRNAs decreased, while FMRP-binding targets increased. Remarkably, we observed the opposite changes of FMRP binding targets in Fmr1-/y hippocampi. In wild-type hippocampus, induction of mGluR-LTD caused rapid changes in the steady-state levels of hundreds of mRNAs, many of which are FMRP targets. Moreover, mGluR-LTD failed to promote phosphorylation of eukaryotic elongation factor 2 (eEF2) in TSC mice, and chemically mimicking phospho-eEF2 with low cycloheximide enhances mGluR-LTD in TSC mice. CONCLUSION These results suggest a molecular basis for bidirectional regulation of synaptic plasticity and behavior by TSC2 and FMRP. Our study also suggests that altered mGluR-regulated translation elongation contributes to impaired synaptic plasticity in Tsc2+/- mice.
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Affiliation(s)
- Annie Hien
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, MA, 01605, USA
- Medical Scientist Training Program, University of Massachusetts Medical School, Worcester, MA, 01655, USA
| | - Gemma Molinaro
- Department of Neuroscience, University of Texas Southwestern Medical Center, Dallas, TX, 75390, USA
| | - Botao Liu
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, MA, 01605, USA
| | - Kimberly M Huber
- Department of Neuroscience, University of Texas Southwestern Medical Center, Dallas, TX, 75390, USA.
| | - Joel D Richter
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, MA, 01605, USA.
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