1
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Singer RA, Rajchin V, Park K, Heintz N, Darnell RB. Opto-CLIP reveals dynamic FMRP regulation of mRNAs upon CA1 neuronal activation. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.08.13.607210. [PMID: 39185177 PMCID: PMC11343148 DOI: 10.1101/2024.08.13.607210] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/27/2024]
Abstract
Neuronal diversity and function are intricately linked to the dynamic regulation of RNA metabolism, including splicing, localization, and translation. Electrophysiologic studies of synaptic plasticity, models for learning and memory, are disrupted in Fragile X Syndrome (FXS). FXS is characterized by the loss of FMRP, an RNA-binding protein (RBP) known to bind and suppress translation of specific neuronal RNAs. Since molecular studies have demonstrated that synaptic plasticity in CA1 excitatory hippocampal neurons is protein-synthesis dependent, together these observations have suggested a potential role for FMRP in synaptic plasticity in FXS. To explore this model, we developed a new experimental platform, Opto-CLIP, to integrate optogenetics with cell-type specific FMRP CLIP and RiboTag in CA1 hippocampal neurons, allowing investigation of FMRP-regulated dynamics after neuronal activation. We tracked changes in FMRP binding and ribosome-associated RNA profiles 30 minutes after neuronal activation. Our findings reveal a significant reduction in FMRP-RNA binding to transcripts encoding nuclear proteins, suggesting FMRP translational inhibition may be de-repressed to allow rapid translational responses required for neuronal homeostasis. In contrast, FMRP binding to transcripts encoding synaptic targets were generally stable after activation, but all categories of targets demonstrated variability in FMRP translational control. Opto-CLIP revealed differential regulation of subsets of transcripts within CA1 neurons rapidly after depolarization, and offers promise as a generally useful platform to uncover mechanisms of RBP-mediated RNA regulation in the context of synaptic plasticity.
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Affiliation(s)
- Ruth A. Singer
- Laboratory of Molecular Neuro-oncology, The Rockefeller University, New York, NY, USA
| | - Veronika Rajchin
- Laboratory of Molecular Neuro-oncology, The Rockefeller University, New York, NY, USA
| | - Kwanghoon Park
- Laboratory of Molecular Biology, The Rockefeller University, New York, NY, USA
| | - Nathaniel Heintz
- Laboratory of Molecular Biology, The Rockefeller University, New York, NY, USA
| | - Robert B. Darnell
- Laboratory of Molecular Neuro-oncology, The Rockefeller University, New York, NY, USA
- Howard Hughes Medical Institute, The Rockefeller University, New York, NY, USA
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2
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Ramakrishna S, Radhakrishna BK, Kaladiyil AP, Shah NM, Basavaraju N, Freude KK, Kommaddi RP, Muddashetty RS. Distinct calcium sources regulate temporal profiles of NMDAR and mGluR-mediated protein synthesis. Life Sci Alliance 2024; 7:e202402594. [PMID: 38749544 PMCID: PMC11096670 DOI: 10.26508/lsa.202402594] [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] [Received: 01/14/2024] [Revised: 05/02/2024] [Accepted: 05/02/2024] [Indexed: 05/18/2024] Open
Abstract
Calcium signaling is integral for neuronal activity and synaptic plasticity. We demonstrate that the calcium response generated by different sources modulates neuronal activity-mediated protein synthesis, another process essential for synaptic plasticity. Stimulation of NMDARs generates a protein synthesis response involving three phases-increased translation inhibition, followed by a decrease in translation inhibition, and increased translation activation. We show that these phases are linked to NMDAR-mediated calcium response. Calcium influx through NMDARs elicits increased translation inhibition, which is necessary for the successive phases. Calcium through L-VGCCs acts as a switch from translation inhibition to the activation phase. NMDAR-mediated translation activation requires the contribution of L-VGCCs, RyRs, and SOCE. Furthermore, we show that IP3-mediated calcium release and SOCE are essential for mGluR-mediated translation up-regulation. Finally, we signify the relevance of our findings in the context of Alzheimer's disease. Using neurons derived from human fAD iPSCs and transgenic AD mice, we demonstrate the dysregulation of NMDAR-mediated calcium and translation response. Our study highlights the complex interplay between calcium signaling and protein synthesis, and its implications in neurodegeneration.
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Affiliation(s)
- Sarayu Ramakrishna
- https://ror.org/04dese585 Centre for Brain Research, Indian Institute of Science, Bangalore, India
| | - Bindushree K Radhakrishna
- https://ror.org/04dese585 Centre for Brain Research, Indian Institute of Science, Bangalore, India
- Manipal Academy of Higher Education, Manipal, India
| | - Ahamed P Kaladiyil
- https://ror.org/04dese585 Centre for Brain Research, Indian Institute of Science, Bangalore, India
| | - Nisa Manzoor Shah
- https://ror.org/04dese585 Centre for Brain Research, Indian Institute of Science, Bangalore, India
- Manipal Academy of Higher Education, Manipal, India
| | - Nimisha Basavaraju
- https://ror.org/04dese585 Centre for Brain Research, Indian Institute of Science, Bangalore, India
- Manipal Academy of Higher Education, Manipal, India
| | - Kristine K Freude
- Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Frederiksberg C, Denmark
| | - Reddy Peera Kommaddi
- https://ror.org/04dese585 Centre for Brain Research, Indian Institute of Science, Bangalore, India
| | - Ravi S Muddashetty
- https://ror.org/04dese585 Centre for Brain Research, Indian Institute of Science, Bangalore, India
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3
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Heimdörfer D, Vorleuter A, Eschlböck A, Spathopoulou A, Suarez-Cubero M, Farhan H, Reiterer V, Spanjaard M, Schaaf CP, Huber LA, Kremser L, Sarg B, Edenhofer F, Geley S, de Araujo MEG, Huettenhofer A. Truncated variants of MAGEL2 are involved in the etiologies of the Schaaf-Yang and Prader-Willi syndromes. Am J Hum Genet 2024; 111:1383-1404. [PMID: 38908375 PMCID: PMC11267527 DOI: 10.1016/j.ajhg.2024.05.023] [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: 04/16/2024] [Revised: 05/27/2024] [Accepted: 05/29/2024] [Indexed: 06/24/2024] Open
Abstract
The neurodevelopmental disorders Prader-Willi syndrome (PWS) and Schaaf-Yang syndrome (SYS) both arise from genomic alterations within human chromosome 15q11-q13. A deletion of the SNORD116 cluster, encoding small nucleolar RNAs, or frameshift mutations within MAGEL2 result in closely related phenotypes in individuals with PWS or SYS, respectively. By investigation of their subcellular localization, we observed that in contrast to a predominant cytoplasmic localization of wild-type (WT) MAGEL2, a truncated MAGEL2 mutant was evenly distributed between the cytoplasm and the nucleus. To elucidate regulatory pathways that may underlie both diseases, we identified protein interaction partners for WT or mutant MAGEL2, in particular the survival motor neuron protein (SMN), involved in spinal muscular atrophy, and the fragile-X-messenger ribonucleoprotein (FMRP), involved in autism spectrum disorders. The interactome of the non-coding RNA SNORD116 was also investigated by RNA-CoIP. We show that WT and truncated MAGEL2 were both involved in RNA metabolism, while regulation of transcription was mainly observed for WT MAGEL2. Hence, we investigated the influence of MAGEL2 mutations on the expression of genes from the PWS locus, including the SNORD116 cluster. Thereby, we provide evidence for MAGEL2 mutants decreasing the expression of SNORD116, SNORD115, and SNORD109A, as well as protein-coding genes MKRN3 and SNRPN, thus bridging the gap between PWS and SYS.
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Affiliation(s)
- David Heimdörfer
- Institute of Genomics and RNomics, Biocenter Innsbruck, Medical University of Innsbruck, Innrain 80/82, 6020 Innsbruck, Austria.
| | - Alexander Vorleuter
- Institute of Genomics and RNomics, Biocenter Innsbruck, Medical University of Innsbruck, Innrain 80/82, 6020 Innsbruck, Austria
| | - Alexander Eschlböck
- Institute for Molecular Biology, Genomics, Stem Cell Biology & Regenerative Medicine Group, University of Innsbruck and CMBI, Technikerstr. 25, 6020 Innsbruck, Austria
| | - Angeliki Spathopoulou
- Institute for Molecular Biology, Genomics, Stem Cell Biology & Regenerative Medicine Group, University of Innsbruck and CMBI, Technikerstr. 25, 6020 Innsbruck, Austria
| | - Marta Suarez-Cubero
- Institute for Molecular Biology, Genomics, Stem Cell Biology & Regenerative Medicine Group, University of Innsbruck and CMBI, Technikerstr. 25, 6020 Innsbruck, Austria
| | - Hesso Farhan
- Institute of Pathophysiology, Biocenter, Medical University of Innsbruck, Innrain 80/82, 6020 Innsbruck, Austria
| | - Veronika Reiterer
- Institute of Pathophysiology, Biocenter, Medical University of Innsbruck, Innrain 80/82, 6020 Innsbruck, Austria
| | - Melanie Spanjaard
- Institute of Human Genetics, Heidelberg University, Im Neuenheimer Feld 366, 69120 Heidelberg, Germany
| | - Christian P Schaaf
- Institute of Human Genetics, Heidelberg University, Im Neuenheimer Feld 366, 69120 Heidelberg, Germany
| | - Lukas A Huber
- Institute of Cell Biology, Biocenter, Medical University of Innsbruck, Innrain 80/82, Innsbruck 6020, Austria
| | - Leopold Kremser
- Institute of Medical Biochemistry, Protein Core Facility, Biocenter, Medical University of Innsbruck, Innrain 80/82, 6020 Innsbruck, Austria
| | - Bettina Sarg
- Institute of Medical Biochemistry, Protein Core Facility, Biocenter, Medical University of Innsbruck, Innrain 80/82, 6020 Innsbruck, Austria
| | - Frank Edenhofer
- Institute for Molecular Biology, Genomics, Stem Cell Biology & Regenerative Medicine Group, University of Innsbruck and CMBI, Technikerstr. 25, 6020 Innsbruck, Austria
| | - Stephan Geley
- Institute of Pathophysiology, Biocenter, Medical University of Innsbruck, Innrain 80/82, 6020 Innsbruck, Austria
| | - Mariana E G de Araujo
- Institute of Cell Biology, Biocenter, Medical University of Innsbruck, Innrain 80/82, Innsbruck 6020, Austria
| | - Alexander Huettenhofer
- Institute of Genomics and RNomics, Biocenter Innsbruck, Medical University of Innsbruck, Innrain 80/82, 6020 Innsbruck, Austria.
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4
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Bai SY, Zeng DY, Ouyang M, Zeng Y, Tan W, Xu L. Synaptic cell adhesion molecules contribute to the pathogenesis and progression of fragile X syndrome. Front Cell Neurosci 2024; 18:1393536. [PMID: 39022311 PMCID: PMC11252757 DOI: 10.3389/fncel.2024.1393536] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2024] [Accepted: 06/19/2024] [Indexed: 07/20/2024] Open
Abstract
Fragile X syndrome (FXS) is the most common form of inherited intellectual disability and a monogenic cause of autism spectrum disorders. Deficiencies in the fragile X messenger ribonucleoprotein, encoded by the FMR1 gene, lead to various anatomical and pathophysiological abnormalities and behavioral deficits, such as spine dysmorphogenesis and learning and memory impairments. Synaptic cell adhesion molecules (CAMs) play crucial roles in synapse formation and neural signal transmission by promoting the formation of new synaptic contacts, accurately organizing presynaptic and postsynaptic protein complexes, and ensuring the accuracy of signal transmission. Recent studies have implicated synaptic CAMs such as the immunoglobulin superfamily, N-cadherin, leucine-rich repeat proteins, and neuroligin-1 in the pathogenesis of FXS and found that they contribute to defects in dendritic spines and synaptic plasticity in FXS animal models. This review systematically summarizes the biological associations between nine representative synaptic CAMs and FMRP, as well as the functional consequences of the interaction, to provide new insights into the mechanisms of abnormal synaptic development in FXS.
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Affiliation(s)
- Shu-Yuan Bai
- Geriatric Hospital Affiliated to Wuhan University of Science and Technology, Wuhan, China
- Hubei Provincial Clinical Research Center for Alzheimer's Disease, Wuhan University of Science and Technology, Wuhan, China
| | - De-Yang Zeng
- Geriatric Hospital Affiliated to Wuhan University of Science and Technology, Wuhan, China
- Hubei Provincial Clinical Research Center for Alzheimer's Disease, Wuhan University of Science and Technology, Wuhan, China
| | - Ming Ouyang
- Geriatric Hospital Affiliated to Wuhan University of Science and Technology, Wuhan, China
- Hubei Provincial Clinical Research Center for Alzheimer's Disease, Wuhan University of Science and Technology, Wuhan, China
| | - Yan Zeng
- Geriatric Hospital Affiliated to Wuhan University of Science and Technology, Wuhan, China
- Hubei Provincial Clinical Research Center for Alzheimer's Disease, Wuhan University of Science and Technology, Wuhan, China
| | - Wei Tan
- Geriatric Hospital Affiliated to Wuhan University of Science and Technology, Wuhan, China
- Hubei Provincial Clinical Research Center for Alzheimer's Disease, Wuhan University of Science and Technology, Wuhan, China
| | - Lang Xu
- Geriatric Hospital Affiliated to Wuhan University of Science and Technology, Wuhan, China
- Hubei Provincial Clinical Research Center for Alzheimer's Disease, Wuhan University of Science and Technology, Wuhan, China
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5
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Kumar A, Laborit Labrada B, Lavallée-Bourget MH, Forest MP, Schwab M, Bellmann K, Houde V, Beauchemin N, Laplante M, Marette A. Regulation of PPARγ2 Stability and Activity by SHP-1. Mol Cell Biol 2024; 44:261-272. [PMID: 38828991 PMCID: PMC11253886 DOI: 10.1080/10985549.2024.2354959] [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: 07/03/2023] [Accepted: 04/23/2024] [Indexed: 06/05/2024] Open
Abstract
The protein tyrosine phosphatase Src homology region 2 domain-containing phosphatase-1 (SHP-1) plays an important role in modulating glucose and lipid homeostasis. We previously suggested a potential role of SHP-1 in the regulation of peroxisome proliferator-activated receptor γ2 (PPARγ2) expression and activity but the mechanisms were unexplored. PPARγ2 is the master regulator of adipogenesis, but how its activity is regulated by tyrosine phosphorylation is largely unknown. Here, we found that SHP-1 binds to PPARγ2 primarily via its N-terminal SH2-domain. We confirmed the phosphorylation of PPARγ2 on tyrosine-residue 78 (Y78), which was reduced by SHP-1 in vitro resulting in decreased PPARγ2 stability. Loss of SHP-1 led to elevated, agonist-induced expression of the classical PPARγ2 targets FABP4 and CD36, concomitant with increased lipid content in cells expressing PPARγ2, an effect blunted by abrogation of PPARγ2 phosphorylation. Collectively, we discovered that SHP-1 affects the stability of PPARγ2 through dephosphorylation thereby influencing adipogenesis.
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Affiliation(s)
- Amit Kumar
- Centre de recherche de l‘Institut universitaire de cardiologie et de pneumologie de Québec (CRIUCPQ), Faculté de Médecine, Université Laval, Québec, QC, Canada
| | - Beisy Laborit Labrada
- Centre de recherche de l‘Institut universitaire de cardiologie et de pneumologie de Québec (CRIUCPQ), Faculté de Médecine, Université Laval, Québec, QC, Canada
| | - Marie-Hélène Lavallée-Bourget
- Centre de recherche de l‘Institut universitaire de cardiologie et de pneumologie de Québec (CRIUCPQ), Faculté de Médecine, Université Laval, Québec, QC, Canada
| | - Marie-Pier Forest
- Centre de recherche de l‘Institut universitaire de cardiologie et de pneumologie de Québec (CRIUCPQ), Faculté de Médecine, Université Laval, Québec, QC, Canada
| | - Michael Schwab
- Centre de recherche de l‘Institut universitaire de cardiologie et de pneumologie de Québec (CRIUCPQ), Faculté de Médecine, Université Laval, Québec, QC, Canada
| | - Kerstin Bellmann
- Centre de recherche de l‘Institut universitaire de cardiologie et de pneumologie de Québec (CRIUCPQ), Faculté de Médecine, Université Laval, Québec, QC, Canada
| | - Vanessa Houde
- Centre de recherche de l‘Institut universitaire de cardiologie et de pneumologie de Québec (CRIUCPQ), Faculté de Médecine, Université Laval, Québec, QC, Canada
| | - Nicole Beauchemin
- Rosalind and Morris Goodman Cancer Research Centre, Departments of Oncology, Medicine and Biochemistry, McGill University, Montreal, QC, Canada
| | - Mathieu Laplante
- Centre de recherche de l‘Institut universitaire de cardiologie et de pneumologie de Québec (CRIUCPQ), Faculté de Médecine, Université Laval, Québec, QC, Canada
- Centre de Recherche sur le Cancer, l’Université Laval, Québec, QC, Canada
| | - André Marette
- Centre de recherche de l‘Institut universitaire de cardiologie et de pneumologie de Québec (CRIUCPQ), Faculté de Médecine, Université Laval, Québec, QC, Canada
- Institute of Nutrition and Functional Foods, Laval University, Québec, QC, Canada
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6
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Kharod SC, Hwang DW, Choi H, Yoon KJ, Castillo PE, Singer RH, Yoon YJ. Phosphorylation alters FMRP granules and determines their transport or protein synthesis abilities. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.03.15.532613. [PMID: 37781583 PMCID: PMC10541110 DOI: 10.1101/2023.03.15.532613] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/03/2023]
Abstract
Fragile X messenger ribonucleoprotein (FMRP) is an RNA-binding protein implicated in autism that suppresses translation and forms granules. While FMRP function has been well-studied, how phosphorylation regulates granule binding and function remains limited. Here, we found that Fragile X patient-derived I304N mutant FMRP could not stably bind granules, underscoring the essential nature of FMRP granule association for function. Next, phosphorylation on serine 499 (S499) led to differences in puncta size, intensity, contrast, and transport as shown by phospho-deficient (S499A) and phospho-mimic (S499D) mutant FMRP granules. Additionally, S499D exchanged slowly on granules relative to S499A, suggesting that phosphorylated FMRP can attenuate translation. Furthermore, the S499A mutant enhanced translation in presynaptic boutons of the mouse hippocampus. Thus, the phospho-state of FMRP altered the structure of individual granules with changes in transport and translation to achieve spatiotemporal regulation of local protein synthesis. Teaser The phosphorylation-state of S499 on FMRP can change FMRP granule structure and function to facilitate processive transport or local protein synthesis.
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7
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Winden KD, Pham TT, Teaney NA, Ruiz J, Chen R, Chen C, Sahin M. Increased degradation of FMRP contributes to neuronal hyperexcitability in tuberous sclerosis complex. Cell Rep 2023; 42:112838. [PMID: 37494191 PMCID: PMC10529098 DOI: 10.1016/j.celrep.2023.112838] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2022] [Revised: 05/12/2023] [Accepted: 07/05/2023] [Indexed: 07/28/2023] Open
Abstract
Autism spectrum disorder (ASD) is a highly prevalent neurodevelopmental disorder, but new therapies have been impeded by a lack of understanding of the pathological mechanisms. Tuberous sclerosis complex (TSC) and fragile X syndrome are associated with alterations in the mechanistic target of rapamycin (mTOR) and fragile X messenger ribonucleoprotein 1 (FMRP), which have been implicated in the development of ASD. Previously, we observed that transcripts associated with FMRP were down-regulated in TSC2-deficient neurons. In this study, we find that FMRP turnover is dysregulated in TSC2-deficient rodent primary neurons and human induced pluripotent stem cell (iPSC)-derived neurons and is dependent on the E3 ubiquitin ligase anaphase-promoting complex. We also demonstrate that overexpression of FMRP can partially rescue hyperexcitability in TSC2-deficient iPSC-derived neurons. These data indicate that FMRP dysregulation represents an important pathological mechanism in the development of abnormal neuronal activity in TSC and illustrate a molecular convergence between these two neurogenetic disorders.
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Affiliation(s)
- Kellen D Winden
- Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Truc T Pham
- Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Nicole A Teaney
- Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Juan Ruiz
- Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Ryan Chen
- Human Neuron Core, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Cidi Chen
- Human Neuron Core, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA; Rosamund Stone Zander Translational Neuroscience Center, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Mustafa Sahin
- Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA; Rosamund Stone Zander Translational Neuroscience Center, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA.
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8
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Jong YJI, Izumi Y, Harmon SK, Zorumski CF, ÓMalley KL. Striatal mGlu 5-mediated synaptic plasticity is independently regulated by location-specific receptor pools and divergent signaling pathways. J Biol Chem 2023; 299:104949. [PMID: 37354970 PMCID: PMC10388212 DOI: 10.1016/j.jbc.2023.104949] [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: 02/13/2023] [Revised: 06/05/2023] [Accepted: 06/07/2023] [Indexed: 06/26/2023] Open
Abstract
Metabotropic glutamate receptor 5 (mGlu5) is widely expressed throughout the central nervous system and is involved in neuronal function, synaptic transmission, and a number of neuropsychiatric disorders such as depression, anxiety, and autism. Recent work from this lab showed that mGlu5 is one of a growing number of G protein-coupled receptors that can signal from intracellular membranes where it drives unique signaling pathways, including upregulation of extracellular signal-regulated kinase (ERK1/2), ETS transcription factor Elk-1, and activity-regulated cytoskeleton-associated protein (Arc). To determine the roles of cell surface mGlu5 as well as the intracellular receptor in a well-known mGlu5 synaptic plasticity model such as long-term depression, we used pharmacological isolation and genetic and physiological approaches to analyze spatially restricted pools of mGlu5 in striatal cultures and slice preparations. Here we show that both intracellular and cell surface receptors activate the phosphatidylinositol-3-kinase-protein kinase B-mammalian target of rapamycin (PI3K/AKT/mTOR) pathway, whereas only intracellular mGlu5 activates protein phosphatase 2 and leads to fragile X mental retardation protein degradation and de novo protein synthesis followed by a protein synthesis-dependent increase in Arc and post-synaptic density protein 95. However, both cell surface and intracellular mGlu5 activation lead to α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor GluA2 internalization and chemically induced long-term depression albeit via different signaling mechanisms. These data underscore the importance of intracellular mGlu5 in the cascade of events associated with sustained synaptic transmission in the striatum.
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Affiliation(s)
- Yuh-Jiin I Jong
- Department of Neuroscience, Washington University School of Medicine, St Louis, Missouri, USA
| | - Yukitoshi Izumi
- Department of Psychiatry, Washington University School of Medicine, St Louis, Missouri, USA; The Taylor Family Institute for Innovative Psychiatric Research, Washington University School of Medicine, St Louis, Missouri, USA
| | - Steven K Harmon
- Department of Neuroscience, Washington University School of Medicine, St Louis, Missouri, USA
| | - Charles F Zorumski
- Department of Neuroscience, Washington University School of Medicine, St Louis, Missouri, USA; Department of Psychiatry, Washington University School of Medicine, St Louis, Missouri, USA; The Taylor Family Institute for Innovative Psychiatric Research, Washington University School of Medicine, St Louis, Missouri, USA
| | - Karen L ÓMalley
- Department of Neuroscience, Washington University School of Medicine, St Louis, Missouri, USA.
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9
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Wilkerson JR, Ifrim MF, Valdez-Sinon AN, Hahn P, Bowles JE, Molinaro G, Janusz-Kaminska A, Bassell GJ, Huber KM. FMRP phosphorylation and interactions with Cdh1 regulate association with dendritic RNA granules and MEF2-triggered synapse elimination. Neurobiol Dis 2023; 182:106136. [PMID: 37120096 PMCID: PMC10370323 DOI: 10.1016/j.nbd.2023.106136] [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: 02/20/2023] [Revised: 04/12/2023] [Accepted: 04/24/2023] [Indexed: 05/01/2023] Open
Abstract
Fragile X Messenger Ribonucleoprotein (FMRP) is necessary for experience-dependent, developmental synapse elimination and the loss of this process may underlie the excess dendritic spines and hyperconnectivity of cortical neurons in Fragile X Syndrome, a common inherited form of intellectual disability and autism. Little is known of the signaling pathways that regulate synapse elimination and if or how FMRP is regulated during this process. We have characterized a model of synapse elimination in CA1 neurons of organotypic hippocampal slice cultures that is induced by expression of the active transcription factor Myocyte Enhancer Factor 2 (MEF2) and relies on postsynaptic FMRP. MEF2-induced synapse elimination is deficient in Fmr1 KO CA1 neurons, and is rescued by acute (24 h), postsynaptic and cell autonomous reexpression of FMRP in CA1 neurons. FMRP is an RNA binding protein that suppresses mRNA translation. Derepression is induced by posttranslational mechanisms downstream of metabotropic glutamate receptor signaling. Dephosphorylation of FMRP at S499 triggers ubiquitination and degradation of FMRP which then relieves translation suppression and promotes synthesis of proteins encoded by target mRNAs. Whether this mechanism functions in synapse elimination is not known. Here we demonstrate that phosphorylation and dephosphorylation of FMRP at S499 are both necessary for synapse elimination as well as interaction of FMRP with its E3 ligase for FMRP, APC/Cdh1. Using a bimolecular ubiquitin-mediated fluorescence complementation (UbFC) assay, we demonstrate that MEF2 promotes ubiquitination of FMRP in CA1 neurons that relies on activity and interaction with APC/Cdh1. Our results suggest a model where MEF2 regulates posttranslational modifications of FMRP via APC/Cdh1 to regulate translation of proteins necessary for synapse elimination.
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Affiliation(s)
- Julia R Wilkerson
- Department of Neuroscience, O'Donnell Brain Institute, UT Southwestern Medical Center, Dallas, TX, USA
| | - Marius F Ifrim
- Department of Cell and Developmental Biology, State University of New York, Upstate Medical University, Syracuse, NY 13210, USA; Department of Cell Biology, Emory University School of Medicine, Atlanta, GA 30322, USA
| | | | - Patricia Hahn
- Department of Neuroscience, O'Donnell Brain Institute, UT Southwestern Medical Center, Dallas, TX, USA
| | - Jacob E Bowles
- Department of Neuroscience, O'Donnell Brain Institute, UT Southwestern Medical Center, Dallas, TX, USA
| | - Gemma Molinaro
- Department of Neuroscience, O'Donnell Brain Institute, UT Southwestern Medical Center, Dallas, TX, USA
| | | | - Gary J Bassell
- Department of Cell Biology, Emory University School of Medicine, Atlanta, GA 30322, USA.
| | - Kimberly M Huber
- Department of Neuroscience, O'Donnell Brain Institute, UT Southwestern Medical Center, Dallas, TX, USA.
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10
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Bauer KE, de Queiroz BR, Kiebler MA, Besse F. RNA granules in neuronal plasticity and disease. Trends Neurosci 2023:S0166-2236(23)00104-2. [PMID: 37202301 DOI: 10.1016/j.tins.2023.04.004] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2023] [Revised: 04/11/2023] [Accepted: 04/16/2023] [Indexed: 05/20/2023]
Abstract
RNA granules are dynamic entities controlling the spatiotemporal distribution and translation of RNA molecules. In neurons, a variety of RNA granules exist both in the soma and in cellular processes. They contain transcripts encoding signaling and synaptic proteins as well as RNA-binding proteins causally linked to several neurological disorders. In this review, we highlight that neuronal RNA granules exhibit properties of biomolecular condensates that are regulated upon maturation and physiological aging and how they are reversibly remodeled in response to neuronal activity to control local protein synthesis and ultimately synaptic plasticity. Moreover, we propose a framework of how neuronal RNA granules mature over time in healthy conditions and how they transition into pathological inclusions in the context of late-onset neurodegenerative diseases.
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Affiliation(s)
- Karl E Bauer
- Biomedical Center (BMC), Department of Anatomy and Cell Biology, Medical Faculty, Ludwig-Maximilians-University, Planegg-Martinsried, Germany
| | - Bruna R de Queiroz
- Université Côte d'Azur, CNRS, Inserm, Institut de Biologie Valrose, Nice, France
| | - Michael A Kiebler
- Biomedical Center (BMC), Department of Anatomy and Cell Biology, Medical Faculty, Ludwig-Maximilians-University, Planegg-Martinsried, Germany.
| | - Florence Besse
- Université Côte d'Azur, CNRS, Inserm, Institut de Biologie Valrose, Nice, France.
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11
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Fodder K, Murthy M, Rizzu P, Toomey CE, Hasan R, Humphrey J, Raj T, Lunnon K, Mill J, Heutink P, Lashley T, Bettencourt C. Brain DNA methylomic analysis of frontotemporal lobar degeneration reveals OTUD4 in shared dysregulated signatures across pathological subtypes. Acta Neuropathol 2023:10.1007/s00401-023-02583-z. [PMID: 37149835 DOI: 10.1007/s00401-023-02583-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2022] [Revised: 04/28/2023] [Accepted: 04/28/2023] [Indexed: 05/08/2023]
Abstract
Frontotemporal lobar degeneration (FTLD) is an umbrella term describing the neuropathology of a clinically, genetically and pathologically heterogeneous group of diseases, including frontotemporal dementia (FTD) and progressive supranuclear palsy (PSP). Among the major FTLD pathological subgroups, FTLD with TDP-43 positive inclusions (FTLD-TDP) and FTLD with tau-positive inclusions (FTLD-tau) are the most common, representing about 90% of the cases. Although alterations in DNA methylation have been consistently associated with neurodegenerative diseases, including Alzheimer's disease and Parkinson's disease, little is known for FTLD and its heterogeneous subgroups and subtypes. The main goal of this study was to investigate DNA methylation variation in FTLD-TDP and FTLD-tau. We used frontal cortex genome-wide DNA methylation profiles from three FTLD cohorts (142 FTLD cases and 92 controls), generated using the Illumina 450K or EPIC microarrays. We performed epigenome-wide association studies (EWAS) for each cohort followed by meta-analysis to identify shared differentially methylated loci across FTLD subgroups/subtypes. In addition, we used weighted gene correlation network analysis to identify co-methylation signatures associated with FTLD and other disease-related traits. Wherever possible, we also incorporated relevant gene/protein expression data. After accounting for a conservative Bonferroni multiple testing correction, the EWAS meta-analysis revealed two differentially methylated loci in FTLD, one annotated to OTUD4 (5'UTR-shore) and the other to NFATC1 (gene body-island). Of these loci, OTUD4 showed consistent upregulation of mRNA and protein expression in FTLD. In addition, in the three independent co-methylation networks, OTUD4-containing modules were enriched for EWAS meta-analysis top loci and were strongly associated with the FTLD status. These co-methylation modules were enriched for genes implicated in the ubiquitin system, RNA/stress granule formation and glutamatergic synaptic signalling. Altogether, our findings identified novel FTLD-associated loci, and support a role for DNA methylation as a mechanism involved in the dysregulation of biological processes relevant to FTLD, highlighting novel potential avenues for therapeutic development.
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Affiliation(s)
- Katherine Fodder
- Queen Square Brain Bank for Neurological Disorders, UCL Queen Square Institute of Neurology, London, UK
- Department of Neurodegenerative Disease, UCL Queen Square Institute of Neurology, London, UK
| | - Megha Murthy
- Queen Square Brain Bank for Neurological Disorders, UCL Queen Square Institute of Neurology, London, UK
- Department of Clinical and Movement Neurosciences, UCL Queen Square Institute of Neurology, London, UK
| | - Patrizia Rizzu
- German Center for Neurodegenerative Diseases (DZNE), Tübingen, Germany
| | - Christina E Toomey
- Queen Square Brain Bank for Neurological Disorders, UCL Queen Square Institute of Neurology, London, UK
- Department of Clinical and Movement Neurosciences, UCL Queen Square Institute of Neurology, London, UK
- The Francis Crick Institute, London, UK
| | - Rahat Hasan
- Nash Family Department of Neuroscience and Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Jack Humphrey
- Nash Family Department of Neuroscience and Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Towfique Raj
- Nash Family Department of Neuroscience and Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Katie Lunnon
- Department of Clinical and Biomedical Sciences, Faculty of Health and Life Sciences, University of Exeter, Exeter, UK
| | - Jonathan Mill
- Department of Clinical and Biomedical Sciences, Faculty of Health and Life Sciences, University of Exeter, Exeter, UK
| | - Peter Heutink
- German Center for Neurodegenerative Diseases (DZNE), Tübingen, Germany
- Alector, Inc., South San Francisco, CA, USA
| | - Tammaryn Lashley
- Queen Square Brain Bank for Neurological Disorders, UCL Queen Square Institute of Neurology, London, UK
- Department of Neurodegenerative Disease, UCL Queen Square Institute of Neurology, London, UK
| | - Conceição Bettencourt
- Queen Square Brain Bank for Neurological Disorders, UCL Queen Square Institute of Neurology, London, UK.
- Department of Neurodegenerative Disease, UCL Queen Square Institute of Neurology, London, UK.
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12
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Reyes CJF, Asano K. Between Order and Chaos: Understanding the Mechanism and Pathology of RAN Translation. Biol Pharm Bull 2023; 46:139-146. [PMID: 36724941 DOI: 10.1248/bpb.b22-00448] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Repeat-associated non-AUG (RAN) translation is a pathogenic mechanism in which repetitive sequences are translated into aggregation-prone proteins from multiple reading frames, even without a canonical AUG start codon. Since its discovery in spinocerebellar ataxia type 8 (SCA8) and myotonic dystrophy type 1 (DM1), RAN translation is now known to occur in the context of 12 disease-linked repeat expansions. This review discusses recent advances in understanding the regulatory mechanisms controlling RAN translation and its contribution to the pathophysiology of repeat expansion diseases. We discuss the key findings in the context of Fragile X Tremor Ataxia Syndrome (FXTAS), a neurodegenerative disorder caused by a CGG repeat expansion in the 5' untranslated region of FMR1.
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Affiliation(s)
| | - Katsura Asano
- Molecular Cellular and Developmental Biology Program, Division of Biology, Kansas State University.,Laboratory of Translational Control Study, Graduate School of Integrated Sciences for Life, Hiroshima University.,Hiroshima Research Center for Healthy Aging, Hiroshima University
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13
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Nabariya DK, Heinz A, Derksen S, Krauß S. Intracellular and intercellular transport of RNA organelles in CXG repeat disorders: The strength of weak ties. Front Mol Biosci 2022; 9:1000932. [PMID: 36589236 PMCID: PMC9800848 DOI: 10.3389/fmolb.2022.1000932] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2022] [Accepted: 12/06/2022] [Indexed: 12/23/2022] Open
Abstract
RNA is a vital biomolecule, the function of which is tightly spatiotemporally regulated. RNA organelles are biological structures that either membrane-less or surrounded by membrane. They are produced by the all the cells and indulge in vital cellular mechanisms. They include the intracellular RNA granules and the extracellular exosomes. RNA granules play an essential role in intracellular regulation of RNA localization, stability and translation. Aberrant regulation of RNA is connected to disease development. For example, in microsatellite diseases such as CXG repeat expansion disorders, the mutant CXG repeat RNA's localization and function are affected. RNA is not only transported intracellularly but can also be transported between cells via exosomes. The loading of the exosomes is regulated by RNA-protein complexes, and recent studies show that cytosolic RNA granules and exosomes share common content. Intracellular RNA granules and exosome loading may therefore be related. Exosomes can also transfer pathogenic molecules of CXG diseases from cell to cell, thereby driving disease progression. Both intracellular RNA granules and extracellular RNA vesicles may serve as a source for diagnostic and treatment strategies. In therapeutic approaches, pharmaceutical agents may be loaded into exosomes which then transport them to the desired cells/tissues. This is a promising target specific treatment strategy with few side effects. With respect to diagnostics, disease-specific content of exosomes, e.g., RNA-signatures, can serve as attractive biomarker of central nervous system diseases detecting early physiological disturbances, even before symptoms of neurodegeneration appear and irreparable damage to the nervous system occurs. In this review, we summarize the known function of cytoplasmic RNA granules and extracellular vesicles, as well as their role and dysfunction in CXG repeat expansion disorders. We also provide a summary of established protocols for the isolation and characterization of both cytoplasmic and extracellular RNA organelles.
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Affiliation(s)
| | | | | | - Sybille Krauß
- Human Biology/Neurobiology, Institute of Biology, Faculty IV, School of Science and Technology, University of Siegen, Siegen, Germany
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14
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Kurosaki T, Mitsutomi S, Hewko A, Akimitsu N, Maquat LE. Integrative omics indicate FMRP sequesters mRNA from translation and deadenylation in human neuronal cells. Mol Cell 2022; 82:4564-4581.e11. [PMID: 36356584 PMCID: PMC9753132 DOI: 10.1016/j.molcel.2022.10.018] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2022] [Revised: 08/17/2022] [Accepted: 10/18/2022] [Indexed: 11/10/2022]
Abstract
How fragile X syndrome protein (FMRP) binds mRNAs and regulates mRNA metabolism remains unclear. Our previous work using human neuronal cells focused on mRNAs targeted for nonsense-mediated mRNA decay (NMD), which we showed are generally bound by FMRP and destabilized upon FMRP loss. Here, we identify >400 high-confidence FMRP-bound mRNAs, only ∼35% of which are NMD targets. Integrative transcriptomics together with SILAC-LC-MS/MS reveal that FMRP loss generally results in mRNA destabilization and more protein produced per FMRP target. We use our established RIP-seq technology to show that FMRP footprints are independent of protein-coding potential, target GC-rich and structured sequences, and are densest in 5' UTRs. Regardless of where within an mRNA FMRP binds, we find that FMRP protects mRNAs from deadenylation and directly binds the cytoplasmic poly(A)-binding protein. Our results reveal how FMRP sequesters polyadenylated mRNAs into stabilized and translationally repressed complexes, whose regulation is critical for neurogenesis and synaptic plasticity.
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Affiliation(s)
- Tatsuaki Kurosaki
- Department of Biochemistry and Biophysics, School of Medicine and Dentistry, University of Rochester, Rochester, NY 14642, USA; Center for RNA Biology, University of Rochester, Rochester, NY 14642, USA.
| | - Shuhei Mitsutomi
- Department of Biochemistry and Biophysics, School of Medicine and Dentistry, University of Rochester, Rochester, NY 14642, USA; Center for RNA Biology, University of Rochester, Rochester, NY 14642, USA; Isotope Science Center, The University of Tokyo, 2-11-16 Yayoi, Bunkyo-ku, Tokyo 113-0032, Japan
| | - Alexander Hewko
- Department of Biochemistry and Biophysics, School of Medicine and Dentistry, University of Rochester, Rochester, NY 14642, USA; Center for RNA Biology, University of Rochester, Rochester, NY 14642, USA
| | - Nobuyoshi Akimitsu
- Isotope Science Center, The University of Tokyo, 2-11-16 Yayoi, Bunkyo-ku, Tokyo 113-0032, Japan
| | - Lynne E Maquat
- Department of Biochemistry and Biophysics, School of Medicine and Dentistry, University of Rochester, Rochester, NY 14642, USA; Center for RNA Biology, University of Rochester, Rochester, NY 14642, USA.
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15
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D'Souza MN, Ramakrishna S, Radhakrishna BK, Jhaveri V, Ravindran S, Yeramala L, Nair D, Palakodeti D, Muddashetty RS. Function of FMRP Domains in Regulating Distinct Roles of Neuronal Protein Synthesis. Mol Neurobiol 2022; 59:7370-7392. [PMID: 36181660 DOI: 10.1007/s12035-022-03049-1] [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: 01/11/2022] [Accepted: 09/09/2022] [Indexed: 11/24/2022]
Abstract
The Fragile-X Mental Retardation Protein (FMRP) is an RNA binding protein that regulates translation of mRNAs essential for synaptic development and plasticity. FMRP interacts with a specific set of mRNAs, aids in their microtubule-dependent transport and regulates their translation through its association with ribosomes. However, the biochemical role of FMRP's domains in forming neuronal granules and associating with microtubules and ribosomes is currently undefined. We report that the C-terminus domain of FMRP is sufficient to bind to ribosomes akin to the full-length protein. Furthermore, the C-terminus domain alone is essential and responsible for FMRP-mediated neuronal translation repression. However, dendritic distribution of FMRP and its microtubule association is favored by the synergistic combination of FMRP domains rather than individual domains. Interestingly, we show that the phosphorylation of hFMRP at Serine-500 is important in modulating the dynamics of translation by controlling ribosome association. This is a fundamental mechanism governing the size and number of FMRP puncta that contain actively translating ribosomes. Finally through the use of pathogenic mutations, we emphasize the hierarchical contribution of FMRP's domains in translation regulation.
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Affiliation(s)
- Michelle Ninochka D'Souza
- Institute for Stem Cell Science and Regenerative Medicine, Bangalore, India, 560065.,The University of Trans-Disciplinary Health Sciences and Technology (TDU), Bangalore, India, 560064.,Centre for Brain Research, Indian Institute of Science, CV Raman Avenue, Bangalore, India, 560012
| | - Sarayu Ramakrishna
- Institute for Stem Cell Science and Regenerative Medicine, Bangalore, India, 560065.,The University of Trans-Disciplinary Health Sciences and Technology (TDU), Bangalore, India, 560064.,Centre for Brain Research, Indian Institute of Science, CV Raman Avenue, Bangalore, India, 560012
| | | | - Vishwaja Jhaveri
- Institute for Stem Cell Science and Regenerative Medicine, Bangalore, India, 560065
| | - Sreenath Ravindran
- Institute for Stem Cell Science and Regenerative Medicine, Bangalore, India, 560065
| | - Lahari Yeramala
- National Centre For Biological Sciences, Tata Institute of Fundamental Research, Bangalore, India, 560065
| | - Deepak Nair
- Centre for Neuroscience, Indian Institute of Science, Bangalore, India, 560012
| | - Dasaradhi Palakodeti
- Institute for Stem Cell Science and Regenerative Medicine, Bangalore, India, 560065
| | - Ravi S Muddashetty
- Centre for Brain Research, Indian Institute of Science, CV Raman Avenue, Bangalore, India, 560012.
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16
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Development of single-molecule ubiquitination mediated fluorescence complementation to visualize protein ubiquitination dynamics in dendrites. Cell Rep 2022; 41:111658. [PMID: 36384114 PMCID: PMC9795412 DOI: 10.1016/j.celrep.2022.111658] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2022] [Revised: 06/13/2022] [Accepted: 10/21/2022] [Indexed: 11/17/2022] Open
Abstract
The ubiquitination/proteasome system is important for the spatiotemporal control of protein synthesis and degradation at synapses, while dysregulation may underlie autism spectrum disorders (ASDs). However, methods allowing direct visualization of the subcellular localization and temporal dynamics of protein ubiquitination are lacking. Here we report the development of Single-Molecule Ubiquitin Mediated Fluorescence Complementation (SM-UbFC) as a method to visualize and quantify the dynamics of protein ubiquitination in dendrites of live neurons in culture. Using SM-UbFC, we demonstrate that the rate of PSD-95 ubiquitination is elevated in dendrites of FMR1 KO neurons compared with wild-type controls. We further demonstrate the rapid ubiquitination of the fragile X messenger ribonucleoprotein, FMRP, and the AMPA receptor subunit, GluA1, which are known to be key events in the regulation of synaptic protein synthesis and plasticity. SM-UbFC will be useful for future studies on the regulation of synaptic protein homeostasis.
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17
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Malone TJ, Kaczmarek LK. The role of altered translation in intellectual disability and epilepsy. Prog Neurobiol 2022; 213:102267. [PMID: 35364140 PMCID: PMC10583652 DOI: 10.1016/j.pneurobio.2022.102267] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Revised: 02/18/2022] [Accepted: 03/24/2022] [Indexed: 11/29/2022]
Abstract
A very high proportion of cases of intellectual disability are genetic in origin and are associated with the occurrence of epileptic seizures during childhood. These two disorders together effect more than 5% of the world's population. One feature linking the two diseases is that learning and memory require the synthesis of new synaptic components and ion channels, while maintenance of overall excitability also requires synthesis of similar proteins in response to altered neuronal stimulation. Many of these disorders result from mutations in proteins that regulate mRNA processing, translation initiation, translation elongation, mRNA stability or upstream translation modulators. One theme that emerges on reviewing this field is that mutations in proteins that regulate changes in translation following neuronal stimulation are more likely to result in epilepsy with intellectual disability than general translation regulators with no known role in activity-dependent changes. This is consistent with the notion that activity-dependent translation in neurons differs from that in other cells types in that the changes in local cellular composition, morphology and connectivity that occur generally in response to stimuli are directly coupled to local synaptic activity and persist for months or years after the original stimulus.
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Affiliation(s)
- Taylor J Malone
- Departments of Pharmacology, and of Cellular & Molecular Physiology, Yale University, 333 Cedar Street B-309, New Haven, CT 06520, USA
| | - Leonard K Kaczmarek
- Departments of Pharmacology, and of Cellular & Molecular Physiology, Yale University, 333 Cedar Street B-309, New Haven, CT 06520, USA.
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18
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Khlebodarova TM. The molecular view of mechanical stress of brain cells, local translation, and neurodegenerative diseases. Vavilovskii Zhurnal Genet Selektsii 2021; 25:92-100. [PMID: 34901706 PMCID: PMC8629365 DOI: 10.18699/vj21.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2020] [Revised: 12/21/2020] [Accepted: 12/22/2020] [Indexed: 12/03/2022] Open
Abstract
The assumption that chronic mechanical stress in brain cells stemming from intracranial hypertension,
arterial hypertension, or mechanical injury is a risk factor for neurodegenerative diseases was put forward in the
1990s and has since been supported. However, the molecular mechanisms that underlie the way from cell exposure to mechanical stress to disturbances in synaptic plasticity followed by changes in behavior, cognition, and
memory are still poorly understood. Here we review (1) the current knowledge of molecular mechanisms regulating local translation and the actin cytoskeleton state at an activated synapse, where they play a key role in the
formation of various sorts of synaptic plasticity and long-term memory, and (2) possible pathways of mechanical
stress intervention. The roles of the mTOR (mammalian target of rapamycin) signaling pathway; the RNA-binding
FMRP protein; the CYFIP1 protein, interacting with FMRP; the family of small GTPases; and the WAVE regulatory
complex in the regulation of translation initiation and actin cytoskeleton rearrangements in dendritic spines of the
activated synapse are discussed. Evidence is provided that chronic mechanical stress may result in aberrant activation of mTOR signaling and the WAVE regulatory complex via the YAP/TAZ system, the key sensor of mechanical
signals, and influence the associated pathways regulating the formation of F actin filaments and the dendritic spine
structure. These consequences may be a risk factor for various neurological conditions, including autistic spectrum
disorders and epileptic encephalopathy. In further consideration of the role of the local translation system in the
development of neuropsychic and neurodegenerative diseases, an original hypothesis was put forward that one
of the possible causes of synaptopathies is impaired proteome stability associated with mTOR hyperactivity and
formation of complex dynamic modes of de novo protein synthesis in response to synapse-stimulating factors,
including chronic mechanical stress.
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Affiliation(s)
- T M Khlebodarova
- Institute of Cytology and Genetics of Siberian Branch of the Russian Academy of Sciences, Novosibirsk, Russia Kurchatov Genomic Center of the Institute of Cytology and Genetics of Siberian Branch of the Russian Academy of Sciences, Novosibirsk, Russia
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19
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Hagerman RJ, Hagerman PJ. Fragile X Syndrome: Lessons Learned and What New Treatment Avenues Are on the Horizon. Annu Rev Pharmacol Toxicol 2021; 62:365-381. [PMID: 34499526 DOI: 10.1146/annurev-pharmtox-052120-090147] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Fragile X syndrome (FXS) is the most common form of inherited intellectual disability and the leading single-gene form of autism spectrum disorder, encompassing cognitive, behavioral, and physical forms of clinical involvement. FXS is caused by large expansions of a noncoding CGG repeat (>200 repeats) in the FMR1 gene, at which point the gene is generally silenced. Absence of FMR1 protein (FMRP), important for synaptic development and maintenance, gives rise to the neurodevelopmental disorder. There is, at present, no therapeutic approach that directly reverses the loss of FMRP; however, there is an increasing number of potential treatments that target the pathways dysregulated in FXS, including those that address the enhanced activity of the mGluR5 pathway and deficits in GABA pathways. Based on studies of targeted therapeutics to date, the prospects are good for one or more effective therapies for FXS in the near future. Expected final online publication date for the Annual Review of Pharmacology and Toxicology, Volume 62 is January 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.
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Affiliation(s)
- Randi J Hagerman
- Department of Pediatrics, University of California, Davis, School of Medicine, Sacramento, California 95817, USA; .,MIND Institute, University of California Davis Health, Sacramento, California 95817, USA
| | - Paul J Hagerman
- MIND Institute, University of California Davis Health, Sacramento, California 95817, USA.,Department of Biochemistry and Molecular Medicine, University of California, Davis, School of Medicine, Davis, California 95616, USA;
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20
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Fetit R, Hillary RF, Price DJ, Lawrie SM. The neuropathology of autism: A systematic review of post-mortem studies of autism and related disorders. Neurosci Biobehav Rev 2021; 129:35-62. [PMID: 34273379 DOI: 10.1016/j.neubiorev.2021.07.014] [Citation(s) in RCA: 49] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2021] [Revised: 05/13/2021] [Accepted: 07/10/2021] [Indexed: 02/07/2023]
Abstract
Post-mortem studies allow for the direct investigation of brain tissue in those with autism and related disorders. Several review articles have focused on aspects of post-mortem abnormalities but none has brought together the entire post-mortem literature. Here, we systematically review the evidence from post-mortem studies of autism, and of related disorders that present with autistic features. The literature consists of a small body of studies with small sample sizes, but several remarkably consistent findings are evident. Cortical layering is largely undisturbed, but there are consistent reductions in minicolumn numbers and aberrant myelination. Transcriptomics repeatedly implicate abberant synaptic, metabolic, proliferation, apoptosis and immune pathways. Sufficient replicated evidence is available to implicate non-coding RNA, aberrant epigenetic profiles, GABAergic, glutamatergic and glial dysfunction in autism pathogenesis. Overall, the cerebellum and frontal cortex are most consistently implicated, sometimes revealing distinct region-specific alterations. The literature on related disorders such as Rett syndrome, Fragile X and copy number variations (CNVs) predisposing to autism is particularly small and inconclusive. Larger studies, matched for gender, developmental stage, co-morbidities and drug treatment are required.
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Affiliation(s)
- Rana Fetit
- Simons Initiative for the Developing Brain, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh, EH8 9XD, UK.
| | - Robert F Hillary
- Centre for Genomic and Experimental Medicine, Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh, EH4 2XU, UK
| | - David J Price
- Simons Initiative for the Developing Brain, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh, EH8 9XD, UK
| | - Stephen M Lawrie
- Division of Psychiatry, Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh, EH10 5HF, UK; Patrick Wild Centre, Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh, EH10 5HF, UK
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21
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Booker SA, Kind PC. Mechanisms regulating input-output function and plasticity of neurons in the absence of FMRP. Brain Res Bull 2021; 175:69-80. [PMID: 34245842 DOI: 10.1016/j.brainresbull.2021.06.025] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2021] [Revised: 06/13/2021] [Accepted: 06/29/2021] [Indexed: 12/12/2022]
Abstract
The function of brain circuits relies on high-fidelity information transfer within neurons. Synaptic inputs arrive primarily at dendrites, where they undergo integration and summation throughout the somatodendritic domain, ultimately leading to the generation of precise patterns of action potentials. Emerging evidence suggests that the ability of neurons to transfer synaptic information and modulate their output is impaired in a number of neurodevelopmental disorders including Fragile X Syndrome. In this review we summarise recent findings that have revealed the pathophysiological and plasticity mechanisms that alter the ability of neurons in sensory and limbic circuits to reliably code information in the absence of FMRP. We examine which aspects of this transform may result directly from the loss of FMRP and those that a result from compensatory or homeostatic alterations to neuronal function. Dissection of the mechanisms leading to altered input-output function of neurons in the absence of FMRP and their effects on regulating neuronal plasticity throughout development could have important implications for potential therapies for Fragile X Syndrome, including directing the timing and duration of different treatment options.
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Affiliation(s)
- Sam A Booker
- Simons Initiative for the Developing Brain, University of Edinburgh, Edinburgh, UK; Patrick Wild Centre for Autism Research, University of Edinburgh, Edinburgh, UK; Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, UK.
| | - Peter C Kind
- Simons Initiative for the Developing Brain, University of Edinburgh, Edinburgh, UK; Patrick Wild Centre for Autism Research, University of Edinburgh, Edinburgh, UK; Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, UK; National Centre for Biological Sciences (NCBS), Bangalore, India.
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22
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Eshraghi M, Karunadharma PP, Blin J, Shahani N, Ricci EP, Michel A, Urban NT, Galli N, Sharma M, Ramírez-Jarquín UN, Florescu K, Hernandez J, Subramaniam S. Mutant Huntingtin stalls ribosomes and represses protein synthesis in a cellular model of Huntington disease. Nat Commun 2021; 12:1461. [PMID: 33674575 PMCID: PMC7935949 DOI: 10.1038/s41467-021-21637-y] [Citation(s) in RCA: 57] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2020] [Accepted: 01/29/2021] [Indexed: 02/08/2023] Open
Abstract
The polyglutamine expansion of huntingtin (mHTT) causes Huntington disease (HD) and neurodegeneration, but the mechanisms remain unclear. Here, we found that mHtt promotes ribosome stalling and suppresses protein synthesis in mouse HD striatal neuronal cells. Depletion of mHtt enhances protein synthesis and increases the speed of ribosomal translocation, while mHtt directly inhibits protein synthesis in vitro. Fmrp, a known regulator of ribosome stalling, is upregulated in HD, but its depletion has no discernible effect on protein synthesis or ribosome stalling in HD cells. We found interactions of ribosomal proteins and translating ribosomes with mHtt. High-resolution global ribosome footprint profiling (Ribo-Seq) and mRNA-Seq indicates a widespread shift in ribosome occupancy toward the 5' and 3' end and unique single-codon pauses on selected mRNA targets in HD cells, compared to controls. Thus, mHtt impedes ribosomal translocation during translation elongation, a mechanistic defect that can be exploited for HD therapeutics.
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Affiliation(s)
- Mehdi Eshraghi
- grid.214007.00000000122199231The Scripps Research Institute, Department of Neuroscience, Jupiter, FL USA
| | - Pabalu P. Karunadharma
- grid.214007.00000000122199231The Scripps Research Institute, Genomic Core, Jupiter, FL USA
| | - Juliana Blin
- grid.462957.b0000 0004 0598 0706Laboratory of Biology and Cellular Modelling at Ecole Normale Supérieure of Lyon, RNA Metabolism in Immunity and Infection Lab, LBMC, Lyon, France
| | - Neelam Shahani
- grid.214007.00000000122199231The Scripps Research Institute, Department of Neuroscience, Jupiter, FL USA
| | - Emiliano P. Ricci
- grid.462957.b0000 0004 0598 0706Laboratory of Biology and Cellular Modelling at Ecole Normale Supérieure of Lyon, RNA Metabolism in Immunity and Infection Lab, LBMC, Lyon, France
| | | | | | - Nicole Galli
- grid.214007.00000000122199231The Scripps Research Institute, Department of Neuroscience, Jupiter, FL USA
| | - Manish Sharma
- grid.214007.00000000122199231The Scripps Research Institute, Department of Neuroscience, Jupiter, FL USA
| | - Uri Nimrod Ramírez-Jarquín
- grid.214007.00000000122199231The Scripps Research Institute, Department of Neuroscience, Jupiter, FL USA
| | - Katie Florescu
- grid.214007.00000000122199231The Scripps Research Institute, Department of Neuroscience, Jupiter, FL USA
| | - Jennifer Hernandez
- grid.214007.00000000122199231The Scripps Research Institute, Department of Neuroscience, Jupiter, FL USA
| | - Srinivasa Subramaniam
- grid.214007.00000000122199231The Scripps Research Institute, Department of Neuroscience, Jupiter, FL USA
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23
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Sévigny M, Bourdeau Julien I, Venkatasubramani JP, Hui JB, Dutchak PA, Sephton CF. FUS contributes to mTOR-dependent inhibition of translation. J Biol Chem 2020; 295:18459-18473. [PMID: 33082139 PMCID: PMC7939483 DOI: 10.1074/jbc.ra120.013801] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2020] [Revised: 10/15/2020] [Indexed: 12/13/2022] Open
Abstract
The amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD)-linked RNA-binding protein called FUS (fused in sarcoma) has been implicated in several aspects of RNA regulation, including mRNA translation. The mechanism by which FUS affects the translation of polyribosomes has not been established. Here we show that FUS can associate with stalled polyribosomes and that this association is sensitive to mTOR (mammalian target of rapamycin) kinase activity. Specifically, we show that FUS association with polyribosomes is increased by Torin1 treatment or when cells are cultured in nutrient-deficient media, but not when cells are treated with rapamycin, the allosteric inhibitor of mTORC1. Moreover, we report that FUS is necessary for efficient stalling of translation because deficient cells are refractory to the inhibition of mTOR-dependent signaling by Torin1. We also show that ALS-linked FUS mutants R521G and P525L associate abundantly with polyribosomes and decrease global protein synthesis. Importantly, the inhibitory effect on translation by FUS is impaired by mutations that reduce its RNA-binding affinity. These findings demonstrate that FUS is an important RNA-binding protein that mediates translational repression through mTOR-dependent signaling and that ALS-linked FUS mutants can cause a toxic gain of function in the cytoplasm by repressing the translation of mRNA at polyribosomes.
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Affiliation(s)
- Myriam Sévigny
- Department of Psychiatry and Neuroscience, CERVO Brain Research Centre, Laval University, Quebec City, Quebec, Canada
| | - Isabelle Bourdeau Julien
- Department of Psychiatry and Neuroscience, CERVO Brain Research Centre, Laval University, Quebec City, Quebec, Canada
| | - Janani Priya Venkatasubramani
- Department of Psychiatry and Neuroscience, CERVO Brain Research Centre, Laval University, Quebec City, Quebec, Canada
| | - Jeremy B Hui
- Department of Psychiatry and Neuroscience, CERVO Brain Research Centre, Laval University, Quebec City, Quebec, Canada
| | - Paul A Dutchak
- Department of Psychiatry and Neuroscience, CERVO Brain Research Centre, Laval University, Quebec City, Quebec, Canada
| | - Chantelle F Sephton
- Department of Psychiatry and Neuroscience, CERVO Brain Research Centre, Laval University, Quebec City, Quebec, Canada.
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24
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Cha IJ, Lee D, Park SS, Chung CG, Kim SY, Jo MG, Kim SY, Lee BH, Lee YS, Lee SB. Ataxin-2 Dysregulation Triggers a Compensatory Fragile X Mental Retardation Protein Decrease in Drosophila C4da Neurons. Mol Cells 2020; 43:870-879. [PMID: 33115979 PMCID: PMC7604024 DOI: 10.14348/molcells.2020.0158] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2020] [Revised: 09/24/2020] [Accepted: 09/24/2020] [Indexed: 12/19/2022] Open
Abstract
Dendrites require precise and timely delivery of protein substrates to distal areas to ensure the correct morphology and function of neurons. Many of these protein substrates are supplied in the form of ribonucleoprotein (RNP) complex consisting of RNA-binding proteins (RBPs) and mRNAs, which are subsequently translated in distal dendritic areas. It remains elusive, however, whether key RBPs supply mRNA according to local demands individually or in a coordinated manner. In this study, we investigated how Drosophila sensory neurons respond to the dysregulation of a disease-associated RBP, Ataxin-2 (ATX2), which leads to dendritic defects. We found that ATX2 plays a crucial role in spacing dendritic branches for the optimal dendritic receptive fields in Drosophila class IV dendritic arborization (C4da) neurons, where both expression level and subcellular location of ATX2 contribute significantly to this effect. We showed that translational upregulation through the expression of eukaryotic translation initiation factor 4E (eIF4E) further enhanced the ATX2-induced dendritic phenotypes. Additionally, we found that the expression level of another disease-associated RBP, fragile X mental retardation protein (FMRP), decreased in both cell bodies and dendrites when neurons were faced with aberrant upregulation of ATX2. Finally, we revealed that the PAM2 motif of ATX2, which mediates its interaction with poly(A)-binding protein (PABP), is potentially necessary for the decrease of FMRP in certain neuronal stress conditions. Collectively, our data suggest that dysregulation of RBPs triggers a compensatory regulation of other functionally-overlapping RBPs to minimize RBP dysregulation-associated aberrations that hinder neuronal homeostasis in dendrites.
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Affiliation(s)
- In Jun Cha
- Department of Brain & Cognitive Sciences, Daegu Gyeongbuk Institute of Science & Technology (DGIST), Daegu 42988, Korea
- Protein Dynamics-Based Proteotoxicity Control Laboratory, Basic Research Lab, DGIST, Daegu 42988, Korea
| | - Davin Lee
- Department of Brain & Cognitive Sciences, Daegu Gyeongbuk Institute of Science & Technology (DGIST), Daegu 42988, Korea
- Protein Dynamics-Based Proteotoxicity Control Laboratory, Basic Research Lab, DGIST, Daegu 42988, Korea
| | - Sung Soon Park
- Department of Brain & Cognitive Sciences, Daegu Gyeongbuk Institute of Science & Technology (DGIST), Daegu 42988, Korea
- Protein Dynamics-Based Proteotoxicity Control Laboratory, Basic Research Lab, DGIST, Daegu 42988, Korea
| | - Chang Geon Chung
- Department of Brain & Cognitive Sciences, Daegu Gyeongbuk Institute of Science & Technology (DGIST), Daegu 42988, Korea
- Protein Dynamics-Based Proteotoxicity Control Laboratory, Basic Research Lab, DGIST, Daegu 42988, Korea
| | - Seung Yeon Kim
- Department of Brain & Cognitive Sciences, Daegu Gyeongbuk Institute of Science & Technology (DGIST), Daegu 42988, Korea
- Protein Dynamics-Based Proteotoxicity Control Laboratory, Basic Research Lab, DGIST, Daegu 42988, Korea
| | - Min Gu Jo
- Department of Brain & Cognitive Sciences, Daegu Gyeongbuk Institute of Science & Technology (DGIST), Daegu 42988, Korea
- Protein Dynamics-Based Proteotoxicity Control Laboratory, Basic Research Lab, DGIST, Daegu 42988, Korea
| | - Seung Yeol Kim
- Department of Brain & Cognitive Sciences, Daegu Gyeongbuk Institute of Science & Technology (DGIST), Daegu 42988, Korea
- Protein Dynamics-Based Proteotoxicity Control Laboratory, Basic Research Lab, DGIST, Daegu 42988, Korea
| | - Byung-Hoon Lee
- Protein Dynamics-Based Proteotoxicity Control Laboratory, Basic Research Lab, DGIST, Daegu 42988, Korea
- Department of New Biology, DGIST, Daegu 42988, Korea
| | - Young-Sam Lee
- Protein Dynamics-Based Proteotoxicity Control Laboratory, Basic Research Lab, DGIST, Daegu 42988, Korea
- Department of New Biology, DGIST, Daegu 42988, Korea
- Well Aging Research Center, Division of Biotechnology, DGIST, Daegu 42988, Korea
| | - Sung Bae Lee
- Department of Brain & Cognitive Sciences, Daegu Gyeongbuk Institute of Science & Technology (DGIST), Daegu 42988, Korea
- Protein Dynamics-Based Proteotoxicity Control Laboratory, Basic Research Lab, DGIST, Daegu 42988, Korea
- Well Aging Research Center, Division of Biotechnology, DGIST, Daegu 42988, Korea
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25
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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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26
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Clifton NE, Thomas KL, Wilkinson LS, Hall J, Trent S. FMRP and CYFIP1 at the Synapse and Their Role in Psychiatric Vulnerability. Complex Psychiatry 2020; 6:5-19. [PMID: 34883502 PMCID: PMC7673588 DOI: 10.1159/000506858] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2020] [Accepted: 02/27/2020] [Indexed: 12/23/2022] Open
Abstract
There is increasing awareness of the role genetic risk variants have in mediating vulnerability to psychiatric disorders such as schizophrenia and autism. Many of these risk variants encode synaptic proteins, influencing biological pathways of the postsynaptic density and, ultimately, synaptic plasticity. Fragile-X mental retardation 1 (FMR1) and cytoplasmic fragile-X mental retardation protein (FMRP)-interacting protein 1 (CYFIP1) contain 2 such examples of highly penetrant risk variants and encode synaptic proteins with shared functional significance. In this review, we discuss the biological actions of FMRP and CYFIP1, including their regulation of (i) protein synthesis and specifically FMRP targets, (ii) dendritic and spine morphology, and (iii) forms of synaptic plasticity such as long-term depression. We draw upon a range of preclinical studies that have used genetic dosage models of FMR1 and CYFIP1 to determine their biological function. In parallel, we discuss how clinical studies of fragile X syndrome or 15q11.2 deletion patients have informed our understanding of FMRP and CYFIP1, and highlight the latest psychiatric genomic findings that continue to implicate FMRP and CYFIP1. Lastly, we assess the current limitations in our understanding of FMRP and CYFIP1 biology and how they must be addressed before mechanism-led therapeutic strategies can be developed for psychiatric disorders.
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Affiliation(s)
- Nicholas E. Clifton
- Neuroscience & Mental Health Research Institute, Cardiff University, Cardiff, United Kingdom
- MRC Centre for Neuropsychiatric Genetics and Genomics, School of Medicine, Cardiff University, Cardiff, United Kingdom
| | - Kerrie L. Thomas
- Neuroscience & Mental Health Research Institute, Cardiff University, Cardiff, United Kingdom
- School of Biosciences, Cardiff University, Cardiff, United Kingdom
| | - Lawrence S. Wilkinson
- Neuroscience & Mental Health Research Institute, Cardiff University, Cardiff, United Kingdom
- School of Psychology, Cardiff University, Cardiff, United Kingdom
| | - Jeremy Hall
- Neuroscience & Mental Health Research Institute, Cardiff University, Cardiff, United Kingdom
- MRC Centre for Neuropsychiatric Genetics and Genomics, School of Medicine, Cardiff University, Cardiff, United Kingdom
- Division of Psychological Medicine and Clinical Neurosciences, School of Medicine, Cardiff University, Cardiff, United Kingdom
| | - Simon Trent
- Neuroscience & Mental Health Research Institute, Cardiff University, Cardiff, United Kingdom
- School of Life Sciences, Faculty of Natural Sciences, Keele University, Keele, United Kingdom
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27
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Prieto M, Folci A, Martin S. Post-translational modifications of the Fragile X Mental Retardation Protein in neuronal function and dysfunction. Mol Psychiatry 2020; 25:1688-1703. [PMID: 31822816 DOI: 10.1038/s41380-019-0629-4] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/28/2019] [Revised: 11/22/2019] [Accepted: 11/27/2019] [Indexed: 12/17/2022]
Abstract
The Fragile X Mental Retardation Protein (FMRP) is an RNA-binding protein essential to the regulation of local translation at synapses. In the mammalian brain, synapses are constantly formed and eliminated throughout development to achieve functional neuronal networks. At the molecular level, thousands of proteins cooperate to accomplish efficient neuronal communication. Therefore, synaptic protein levels and their functional interactions need to be tightly regulated. FMRP generally acts as a translational repressor of its mRNA targets. FMRP is the target of several post-translational modifications (PTMs) that dynamically regulate its function. Here we provide an overview of the PTMs controlling the FMRP function and discuss how their spatiotemporal interplay contributes to the physiological regulation of FMRP. Importantly, FMRP loss-of-function leads to Fragile X syndrome (FXS), a rare genetic developmental condition causing a range of neurological alterations including intellectual disability (ID), learning and memory impairments, autistic-like features and seizures. Here, we also explore the possibility that recently reported missense mutations in the FMR1 gene disrupt the PTM homoeostasis of FMRP, thus participating in the aetiology of FXS. This suggests that the pharmacological targeting of PTMs may be a promising strategy to develop innovative therapies for patients carrying such missense mutations.
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Affiliation(s)
- Marta Prieto
- Université Côte d'Azur, CNRS, IPMC, Valbonne, France
| | | | - Stéphane Martin
- Université Côte d'Azur, INSERM, CNRS, IPMC, Valbonne, France.
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28
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Lai A, Valdez-Sinon AN, Bassell GJ. Regulation of RNA granules by FMRP and implications for neurological diseases. Traffic 2020; 21:454-462. [PMID: 32374065 PMCID: PMC7377269 DOI: 10.1111/tra.12733] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2020] [Revised: 04/29/2020] [Accepted: 04/29/2020] [Indexed: 12/14/2022]
Abstract
RNA granule formation, which can be regulated by RNA-binding proteins (RBPs) such as fragile X mental retardation protein (FMRP), acts as a mechanism to control both the repression and subcellular localization of translation. Dysregulated assembly of RNA granules has been implicated in multiple neurological disorders, such as amyotrophic lateral sclerosis. Thus, it is crucial to understand the cellular pathways impinging upon granule assembly or disassembly. The goal of this review is to summarize recent advances in our understanding of the role of the RBP, FMRP, in translational repression underlying RNA granule dynamics, mRNA transport and localized. We summarize the known mechanisms of translational regulation by FMRP, the role of FMRP in RNA transport granules, fragile X granules and stress granules. Focusing on the emerging link between FMRP and stress granules, we propose a model for how hyperassembly and hypoassembly of RNA granules may contribute to neurological diseases.
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Affiliation(s)
- Austin Lai
- Department of Cell Biology, Emory University School of Medicine, Atlanta, Georgia, USA
| | | | - Gary J Bassell
- Department of Cell Biology, Emory University School of Medicine, Atlanta, Georgia, USA
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29
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Ghosh Dastidar S, Das Sharma S, Chakraborty S, Chattarji S, Bhattacharya A, Muddashetty RS. Distinct regulation of bioenergetics and translation by group I mGluR and NMDAR. EMBO Rep 2020; 21:e48037. [PMID: 32351028 PMCID: PMC7271334 DOI: 10.15252/embr.201948037] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2019] [Revised: 03/12/2020] [Accepted: 03/27/2020] [Indexed: 12/11/2022] Open
Abstract
Neuronal activity is responsible for the high energy consumption in the brain. However, the cellular mechanisms draining ATP upon the arrival of a stimulus are yet to be explored systematically at the post-synapse. Here, we provide evidence that a significant fraction of ATP is consumed upon glutamate stimulation to energize mGluR-induced protein synthesis. We find that both mGluR and NMDAR alter protein synthesis and ATP consumption with distinct kinetics at the synaptic-dendritic compartments. While mGluR activation leads to a rapid and sustained reduction in neuronal ATP levels, NMDAR activation has no immediate impact on the same. ATP consumption correlates inversely with the kinetics of protein synthesis for both receptors. We observe a persistent elevation in protein synthesis within 5 minutes of mGluR activation and a robust inhibition of the same within 2 minutes of NMDAR activation, assessed by the phosphorylation status of eEF2 and metabolic labeling. However, a delayed protein synthesis-dependent ATP expenditure ensues after 15 minutes of NMDAR stimulation. We identify a central role for AMPK in the correlation between protein synthesis and ATP consumption. AMPK is dephosphorylated and inhibited upon mGluR activation, while it is phosphorylated upon NMDAR activation. Perturbing AMPK activity disrupts receptor-specific modulations of eEF2 phosphorylation and protein synthesis. Our observations, therefore, demonstrate that the regulation of the AMPK-eEF2 signaling axis by glutamate receptors alters neuronal protein synthesis and bioenergetics.
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Affiliation(s)
- Sudhriti Ghosh Dastidar
- Institute for Stem Cell Sciences and Regenerative MedicineBangaloreIndia
- Manipal Academy of Higher EducationManipalIndia
| | - Shreya Das Sharma
- Institute for Stem Cell Sciences and Regenerative MedicineBangaloreIndia
- The University of Trans‐Disciplinary Health Sciences and TechnologyBangaloreIndia
| | - Sumita Chakraborty
- Institute for Stem Cell Sciences and Regenerative MedicineBangaloreIndia
| | - Sumantra Chattarji
- Institute for Stem Cell Sciences and Regenerative MedicineBangaloreIndia
- National Center for Biological SciencesBangaloreIndia
| | - Aditi Bhattacharya
- Institute for Stem Cell Sciences and Regenerative MedicineBangaloreIndia
| | - Ravi S Muddashetty
- Institute for Stem Cell Sciences and Regenerative MedicineBangaloreIndia
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30
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Valdez-Sinon AN, Lai A, Shi L, Lancaster CL, Gokhale A, Faundez V, Bassell GJ. Cdh1-APC Regulates Protein Synthesis and Stress Granules in Neurons through an FMRP-Dependent Mechanism. iScience 2020; 23:101132. [PMID: 32434143 PMCID: PMC7236060 DOI: 10.1016/j.isci.2020.101132] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2019] [Revised: 01/22/2020] [Accepted: 04/28/2020] [Indexed: 12/14/2022] Open
Abstract
Maintaining a balance between protein degradation and protein synthesis is necessary for neurodevelopment. Although the E3 ubiquitin ligase anaphase promoting complex and its regulatory subunit Cdh1 (Cdh1-APC) has been shown to regulate learning and memory, the underlying mechanisms are unclear. Here, we have identified a role of Cdh1-APC as a regulator of protein synthesis in neurons. Proteomic profiling revealed that Cdh1-APC interacts with known regulators of translation, including stress granule proteins. Inhibition of Cdh1-APC activity caused an increase in stress granule formation that is dependent on fragile X mental retardation protein (FMRP). We propose a model in which Cdh1-APC targets stress granule proteins, such as FMRP, and inhibits the formation of stress granules, leading to protein synthesis. Elucidation of a role for Cdh1-APC in regulation of stress granules and protein synthesis in neurons has implications for how Cdh1-APC can regulate protein-synthesis-dependent synaptic plasticity underlying learning and memory.
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Affiliation(s)
| | - Austin Lai
- Department of Cell Biology, Emory University School of Medicine, Atlanta, GA, 30322, USA
| | - Liang Shi
- Department of Cell Biology, Emory University School of Medicine, Atlanta, GA, 30322, USA
| | - Carly L. Lancaster
- Department of Cell Biology, Emory University School of Medicine, Atlanta, GA, 30322, USA
| | - Avanti Gokhale
- Department of Cell Biology, Emory University School of Medicine, Atlanta, GA, 30322, USA
| | - Victor Faundez
- Department of Cell Biology, Emory University School of Medicine, Atlanta, GA, 30322, USA
| | - Gary J. Bassell
- Department of Cell Biology, Emory University School of Medicine, Atlanta, GA, 30322, USA,Corresponding author
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31
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Rodriguez CM, Wright SE, Kearse MG, Haenfler JM, Flores BN, Liu Y, Ifrim MF, Glineburg MR, Krans A, Jafar-Nejad P, Sutton MA, Bassell GJ, Parent JM, Rigo F, Barmada SJ, Todd PK. A native function for RAN translation and CGG repeats in regulating fragile X protein synthesis. Nat Neurosci 2020; 23:386-397. [PMID: 32066985 PMCID: PMC7668390 DOI: 10.1038/s41593-020-0590-1] [Citation(s) in RCA: 41] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2018] [Accepted: 01/10/2020] [Indexed: 02/07/2023]
Abstract
Repeat-associated non-AUG-initiated translation of expanded CGG repeats (CGG RAN) from the FMR1 5'-leader produces toxic proteins that contribute to neurodegeneration in fragile X-associated tremor/ataxia syndrome. Here we describe how unexpanded CGG repeats and their translation play conserved roles in regulating fragile X protein (FMRP) synthesis. In neurons, CGG RAN acts as an inhibitory upstream open reading frame to suppress basal FMRP production. Activation of mGluR5 receptors enhances FMRP synthesis. This enhancement requires both the CGG repeat and CGG RAN initiation sites. Using non-cleaving antisense oligonucleotides (ASOs), we selectively blocked CGG RAN. This ASO blockade enhanced endogenous FMRP expression in human neurons. In human and rodent neurons, CGG RAN-blocking ASOs suppressed repeat toxicity and prolonged survival. These findings delineate a native function for CGG repeats and RAN translation in regulating basal and activity-dependent FMRP synthesis, and they demonstrate the therapeutic potential of modulating CGG RAN translation in fragile X-associated disorders.
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Affiliation(s)
- Caitlin M Rodriguez
- Department of Neurology, University of Michigan, Ann Arbor, MI, USA
- Neuroscience Graduate Program, University of Michigan, Ann Arbor, MI, USA
| | - Shannon E Wright
- Department of Neurology, University of Michigan, Ann Arbor, MI, USA
- Neuroscience Graduate Program, University of Michigan, Ann Arbor, MI, USA
| | - Michael G Kearse
- Department of Neurology, University of Michigan, Ann Arbor, MI, USA
- Department of Biological Chemistry and Pharmacology, Center for RNA Biology, Ohio State University, Columbus, OH, USA
| | - Jill M Haenfler
- Department of Neurology, University of Michigan, Ann Arbor, MI, USA
| | - Brittany N Flores
- Department of Neurology, University of Michigan, Ann Arbor, MI, USA
- Cellular and Molecular Biology Graduate Program, University of Michigan, Ann Arbor, MI, USA
| | - Yu Liu
- Department of Neurology, University of Michigan, Ann Arbor, MI, USA
| | - Marius F Ifrim
- Department of Cell Biology, Emory University School of Medicine, Atlanta, GA, USA
| | - Mary R Glineburg
- Department of Neurology, University of Michigan, Ann Arbor, MI, USA
| | - Amy Krans
- Department of Neurology, University of Michigan, Ann Arbor, MI, USA
- VA Ann Arbor Healthcare System, Ann Arbor, MI, USA
| | | | - Michael A Sutton
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI, USA
| | - Gary J Bassell
- Department of Cell Biology, Emory University School of Medicine, Atlanta, GA, USA
| | - Jack M Parent
- Department of Neurology, University of Michigan, Ann Arbor, MI, USA
- VA Ann Arbor Healthcare System, Ann Arbor, MI, USA
| | - Frank Rigo
- Ionis Pharmaceuticals, Carlsbad, CA, USA
| | - Sami J Barmada
- Department of Neurology, University of Michigan, Ann Arbor, MI, USA
| | - Peter K Todd
- Department of Neurology, University of Michigan, Ann Arbor, MI, USA.
- VA Ann Arbor Healthcare System, Ann Arbor, MI, USA.
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32
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Takabatake M, Goshima Y, Sasaki Y. Semaphorin-3A Promotes Degradation of Fragile X Mental Retardation Protein in Growth Cones via the Ubiquitin-Proteasome Pathway. Front Neural Circuits 2020; 14:5. [PMID: 32184710 PMCID: PMC7059091 DOI: 10.3389/fncir.2020.00005] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2019] [Accepted: 02/07/2020] [Indexed: 01/07/2023] Open
Abstract
Fragile X mental retardation protein (FMRP) is an RNA-binding protein that regulates local translation in dendrites and spines for synaptic plasticity. In axons, FMRP is implicated in axonal extension and axon guidance. We previously demonstrated the involvement of FMRP in growth cone collapse via a translation-dependent response to Semaphorin-3A (Sema3A), a repulsive axon guidance factor. In the case of attractive axon guidance factors, RNA-binding proteins such as zipcode binding protein 1 (ZBP1) accumulate towards the stimulated side of growth cones for local translation. However, it remains unclear how Sema3A effects FMRP localization in growth cones. Here, we show that levels of FMRP in growth cones of hippocampal neurons decreased after Sema3A stimulation. This decrease in FMRP was suppressed by the ubiquitin-activating enzyme E1 enzyme inhibitor PYR-41 and proteasome inhibitor MG132, suggesting that the ubiquitin-proteasome pathway is involved in Sema3A-induced FMRP degradation in growth cones. Moreover, the E1 enzyme or proteasome inhibitor suppressed Sema3A-induced increases in microtubule-associated protein 1B (MAP1B) in growth cones, suggesting that the ubiquitin-proteasome pathway promotes local translation of MAP1B, whose translation is mediated by FMRP. These inhibitors also blocked the Sema3A-induced growth cone collapse. Collectively, our results suggest that Sema3A promotes degradation of FMRP in growth cones through the ubiquitin-proteasome pathway, leading to growth cone collapse via local translation of MAP1B. These findings reveal a new mechanism of axon guidance regulation: degradation of the translational suppressor FMRP via the ubiquitin-proteasome pathway.
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Affiliation(s)
- Masaru Takabatake
- Functional Structure Biology Laboratory, Department of Medical Life Science, Yokohama City University Graduate School of Medical Life Science, Yokohama, Japan
| | - Yoshio Goshima
- Department of Molecular Pharmacology and Neurobiology, Yokohama City University Graduate School of Medicine, Yokohama, Japan
| | - Yukio Sasaki
- Functional Structure Biology Laboratory, Department of Medical Life Science, Yokohama City University Graduate School of Medical Life Science, Yokohama, Japan
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33
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Nawalpuri B, Ravindran S, Muddashetty RS. The Role of Dynamic miRISC During Neuronal Development. Front Mol Biosci 2020; 7:8. [PMID: 32118035 PMCID: PMC7025485 DOI: 10.3389/fmolb.2020.00008] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2019] [Accepted: 01/10/2020] [Indexed: 12/17/2022] Open
Abstract
Activity-dependent protein synthesis plays an important role during neuronal development by fine-tuning the formation and function of neuronal circuits. Recent studies have shown that miRNAs are integral to this regulation because of their ability to control protein synthesis in a rapid, specific and potentially reversible manner. miRNA mediated regulation is a multistep process that involves inhibition of translation before degradation of targeted mRNA, which provides the possibility to store and reverse the inhibition at multiple stages. This flexibility is primarily thought to be derived from the composition of miRNA induced silencing complex (miRISC). AGO2 is likely the only obligatory component of miRISC, while multiple RBPs are shown to be associated with this core miRISC to form diverse miRISC complexes. The formation of these heterogeneous miRISC complexes is intricately regulated by various extracellular signals and cell-specific contexts. In this review, we discuss the composition of miRISC and its functions during neuronal development. Neurodevelopment is guided by both internal programs and external cues. Neuronal activity and external signals play an important role in the formation and refining of the neuronal network. miRISC composition and diversity have a critical role at distinct stages of neurodevelopment. Even though there is a good amount of literature available on the role of miRNAs mediated regulation of neuronal development, surprisingly the role of miRISC composition and its functional dynamics in neuronal development is not much discussed. In this article, we review the available literature on the heterogeneity of the neuronal miRISC composition and how this may influence translation regulation in the context of neuronal development.
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Affiliation(s)
- Bharti Nawalpuri
- Centre for Brain Development and Repair, Institute for Stem Cell Science and Regenerative Medicine (Instem), Bangalore, India.,School of Chemical and Biotechnology, Shanmugha Arts, Science, and Technology and Research Academy (SASTRA) University, Thanjavur, India
| | - Sreenath Ravindran
- Centre for Brain Development and Repair, Institute for Stem Cell Science and Regenerative Medicine (Instem), Bangalore, India.,Manipal Academy of Higher Education, Manipal, India
| | - Ravi S Muddashetty
- Centre for Brain Development and Repair, Institute for Stem Cell Science and Regenerative Medicine (Instem), Bangalore, India
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Roy R, Shiina N, Wang DO. More dynamic, more quantitative, unexpectedly intricate: Advanced understanding on synaptic RNA localization in learning and memory. Neurobiol Learn Mem 2019; 168:107149. [PMID: 31881355 DOI: 10.1016/j.nlm.2019.107149] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2019] [Revised: 10/25/2019] [Accepted: 12/23/2019] [Indexed: 01/13/2023]
Abstract
Synaptic signaling exhibits great diversity, complexity, and plasticity which necessitates maintenance and rapid modification of a local proteome. One solution neurons actively exploit to meet such demands is the strategic deposition of mRNAs encoding proteins for both basal and experience-driven activities into ribonucleoprotein complexes at the synapse. Transcripts localized in this manner can be rapidly accessed for translation in response to a diverse range of stimuli in a temporal- and spatially-restricted manner. Here we review recent findings on localized RNAs and RNA binding proteins in the context of learning and memory, as revealed by cutting-edge in-vitro and in-vivo technologies capable of yielding quantitative and dynamic information. The new technologies include proteomic and transcriptomic analyses, high-resolution multiplexed RNA imaging, single-molecule RNA tracking in living neurons, animal models and human neuron cell models. Among many recent advances in the field, RNA chemical modification has emerged as one of the new regulatory layers of gene expression at synapse that is complex and yet largely unexplored. These exciting new discoveries have enhanced our understanding of the modulation mechanisms of synaptic gene expression and their roles in cognition.
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Affiliation(s)
- Rohini Roy
- Institute for Integrated Cell-Material Sciences (iCeMS), Kyoto University, Kyoto, Japan; Graduate School of Biostudies, Kyoto University, Kyoto, Japan
| | - Nobuyuki Shiina
- Laboratory of Neuronal Cell Biology, National Institute for Basic Biology, Okazaki, Japan; Department of Basic Biology, SOKENDAI, Okazaki, Japan; Exploratory Research Center on Life and Living Systems, Okazaki, Japan.
| | - Dan Ohtan Wang
- Wuya College of Innovation, Shenyang Pharmaceutical University, Liaoning, China; Institute for Integrated Cell-Material Sciences (iCeMS), Kyoto University, Kyoto, Japan; The Keihanshin Consortium for Fostering the Next Generation of Global Leaders in Research (K-CONNEX), Kyoto University, Kyoto, Japan.
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Disruption of GpI mGluR-Dependent Cav2.3 Translation in a Mouse Model of Fragile X Syndrome. J Neurosci 2019; 39:7453-7464. [PMID: 31350260 DOI: 10.1523/jneurosci.1443-17.2019] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2017] [Revised: 06/13/2019] [Accepted: 06/19/2019] [Indexed: 11/21/2022] Open
Abstract
Fragile X syndrome (FXS) is an inherited intellectual impairment that results from the loss of fragile X mental retardation protein (FMRP), an mRNA binding protein that regulates mRNA translation at synapses. The absence of FMRP leads to neuronal and circuit-level hyperexcitability that is thought to arise from the aberrant expression and activity of voltage-gated ion channels, although the identification and characterization of these ion channels have been limited. Here, we show that FMRP binds the mRNA of the R-type voltage-gated calcium channel Cav2.3 in mouse brain synaptoneurosomes and represses Cav2.3 translation under basal conditions. Consequently, in hippocampal neurons from male and female FMRP KO mice, we find enhanced Cav2.3 protein expression by western blotting and abnormally large R currents in whole-cell voltage-clamp recordings. In agreement with previous studies showing that FMRP couples Group I metabotropic glutamate receptor (GpI mGluR) signaling to protein translation, we find that GpI mGluR stimulation results in increased Cav2.3 translation and R current in hippocampal neurons which is disrupted in FMRP KO mice. Thus, FMRP serves as a key translational regulator of Cav2.3 expression under basal conditions and in response to GpI mGluR stimulation. Loss of regulated Cav2.3 expression could underlie the neuronal hyperactivity and aberrant calcium spiking in FMRP KO mice and contribute to FXS, potentially serving as a novel target for future therapeutic strategies.SIGNIFICANCE STATEMENT Patients with fragile X syndrome (FXS) exhibit signs of neuronal and circuit hyperexcitability, including anxiety and hyperactive behavior, attention deficit disorder, and seizures. FXS is caused by the loss of fragile X mental retardation protein (FMRP), an mRNA binding protein, and the neuronal hyperexcitability observed in the absence of FMRP likely results from its ability to regulate the expression and activity of voltage-gated ion channels. Here we find that FMRP serves as a key translational regulator of the voltage-gated calcium channel Cav2.3 under basal conditions and following activity. Cav2.3 impacts cellular excitability and calcium signaling, and the alterations in channel translation and expression observed in the absence of FMRP could contribute to the neuronal hyperactivity that underlies FXS.
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Kute PM, Ramakrishna S, Neelagandan N, Chattarji S, Muddashetty RS. NMDAR mediated translation at the synapse is regulated by MOV10 and FMRP. Mol Brain 2019; 12:65. [PMID: 31291981 PMCID: PMC6617594 DOI: 10.1186/s13041-019-0473-0] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2019] [Accepted: 05/08/2019] [Indexed: 01/08/2023] Open
Abstract
Protein synthesis is crucial for maintaining synaptic plasticity and synaptic signalling. Here we have attempted to understand the role of RNA binding proteins, Fragile X Mental Retardation Protein (FMRP) and Moloney Leukemia Virus 10 (MOV10) protein in N-Methyl-D-Aspartate Receptor (NMDAR) mediated translation regulation. We show that FMRP is required for translation downstream of NMDAR stimulation and MOV10 is the key specificity factor in this process. In rat cortical synaptoneurosomes, MOV10 in association with FMRP and Argonaute 2 (AGO2) forms the inhibitory complex on a subset of NMDAR responsive mRNAs. On NMDAR stimulation, MOV10 dissociates from AGO2 and promotes the translation of its target mRNAs. FMRP is required to form MOV10-AGO2 inhibitory complex and to promote translation of MOV10 associated mRNAs. Phosphorylation of FMRP appears to be the potential switch for NMDAR mediated translation and in the absence of FMRP, the distinct translation response to NMDAR stimulation is lost. Thus, FMRP and MOV10 have an important regulatory role in NMDAR mediated translation at the synapse.
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Affiliation(s)
- Preeti Madhav Kute
- Centre for Brain Development and Repair (CBDR), Institute for Stem Cell Science and Regenerative Medicine (inStem), Bangalore, 560065, India.,School of Chemical and Biotechnology, Shanmugha Arts, Science and Technology & Research Academy (SASTRA) University, Thanjavur, 613401, India
| | - Sarayu Ramakrishna
- Centre for Brain Development and Repair (CBDR), Institute for Stem Cell Science and Regenerative Medicine (inStem), Bangalore, 560065, India.,The University of Trans-Disciplinary Health Sciences and Technology, Bangalore, 560064, India
| | - Nagammal Neelagandan
- Centre for Brain Development and Repair (CBDR), Institute for Stem Cell Science and Regenerative Medicine (inStem), Bangalore, 560065, India
| | - Sumantra Chattarji
- Centre for Brain Development and Repair (CBDR), Institute for Stem Cell Science and Regenerative Medicine (inStem), Bangalore, 560065, India.,National Centre for Biological Sciences (NCBS), Bangalore, 560065, India.,Centre for Discovery Brain Sciences, Deanery of Biomedical Sciences, University of Edinburgh, Edinburgh, EH89XD, UK
| | - Ravi S Muddashetty
- Centre for Brain Development and Repair (CBDR), Institute for Stem Cell Science and Regenerative Medicine (inStem), Bangalore, 560065, India.
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Das R, Schwintzer L, Vinopal S, Aguado Roca E, Sylvester M, Oprisoreanu AM, Schoch S, Bradke F, Broemer M. New roles for the de-ubiquitylating enzyme OTUD4 in an RNA-protein network and RNA granules. J Cell Sci 2019; 132:jcs.229252. [PMID: 31138677 PMCID: PMC6602300 DOI: 10.1242/jcs.229252] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2018] [Accepted: 05/11/2019] [Indexed: 11/20/2022] Open
Abstract
Mechanisms that regulate the formation of membrane-less cellular organelles, such as neuronal RNA granules and stress granules, have gained increasing attention over the past years. These granules consist of RNA and a plethora of RNA-binding proteins. Mutations in RNA-binding proteins have been found in neurodegenerative diseases such as amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). By performing pulldown experiments and subsequent mass spectrometry on mouse brain lysates, we discovered that the de-ubiquitylating enzyme OTU domain-containing protein 4 (OTUD4) unexpectedly is part of a complex network of multiple RNA-binding proteins, including core stress granule factors, such as FMRP (also known as FMR1), SMN1, G3BP1 and TIA1. We show that OTUD4 binds RNA, and that several of its interactions with RNA-binding proteins are RNA dependent. OTUD4 is part of neuronal RNA transport granules in rat hippocampal neurons under physiological conditions, whereas upon cellular stress, OTUD4 is recruited to cytoplasmic stress granules. Knockdown of OTUD4 in HeLa cells resulted in defects in stress granule formation and led to apoptotic cell death. Together, we characterize OTUD4 as a new RNA-binding protein with a suggested function in regulation of translation.
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Affiliation(s)
- Richa Das
- Ubiquitin Signaling Group, German Center for Neurodegenerative Diseases (DZNE), Sigmund-Freud-Str. 27, 53127 Bonn, Germany
| | - Lukas Schwintzer
- Ubiquitin Signaling Group, German Center for Neurodegenerative Diseases (DZNE), Sigmund-Freud-Str. 27, 53127 Bonn, Germany
| | - Stanislav Vinopal
- Axon Growth and Regeneration Group, German Center for Neurodegenerative Diseases (DZNE), Sigmund-Freud-Str. 27, 53127 Bonn, Germany
| | - Eva Aguado Roca
- Ubiquitin Signaling Group, German Center for Neurodegenerative Diseases (DZNE), Sigmund-Freud-Str. 27, 53127 Bonn, Germany
| | - Marc Sylvester
- Institute of Biochemistry and Molecular Biology, Core Facility Mass Spectrometry, University of Bonn, Nussallee 11, 53115 Bonn, Germany
| | - Ana-Maria Oprisoreanu
- Institute of Neuropathology and Department of Epileptology, University of Bonn, Sigmund-Freud-Str. 25, 53127 Bonn, Germany
| | - Susanne Schoch
- Institute of Neuropathology and Department of Epileptology, University of Bonn, Sigmund-Freud-Str. 25, 53127 Bonn, Germany
| | - Frank Bradke
- Axon Growth and Regeneration Group, German Center for Neurodegenerative Diseases (DZNE), Sigmund-Freud-Str. 27, 53127 Bonn, Germany
| | - Meike Broemer
- Ubiquitin Signaling Group, German Center for Neurodegenerative Diseases (DZNE), Sigmund-Freud-Str. 27, 53127 Bonn, Germany
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Westmark CJ. Fragile X and APP: a Decade in Review, a Vision for the Future. Mol Neurobiol 2019; 56:3904-3921. [PMID: 30225775 PMCID: PMC6421119 DOI: 10.1007/s12035-018-1344-x] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2018] [Accepted: 09/05/2018] [Indexed: 10/28/2022]
Abstract
Fragile X syndrome (FXS) is a devastating developmental disability that has profound effects on cognition, behavior, and seizure susceptibility. There are currently no treatments that target the underlying cause of the disorder, and recent clinical trials have been unsuccessful. In 2007, seminal work demonstrated that amyloid-beta protein precursor (APP) is dysregulated in Fmr1KO mice through a metabotropic glutamate receptor 5 (mGluR5)-dependent pathway. These findings raise the hypotheses that: (1) APP and/or APP metabolites are potential therapeutic targets as well as biomarkers for FXS and (2) mGluR5 inhibitors may be beneficial in the treatment of Alzheimer's disease. Herein, advances in the field over the past decade that have reproduced and greatly expanded upon these original findings are reviewed, and required experimentation to validate APP metabolites as potential disease biomarkers as well as therapeutic targets for FXS are discussed.
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Affiliation(s)
- Cara J Westmark
- Department of Neurology, University of Wisconsin-Madison, Medical Sciences Center, Room 3619, 1300 University Avenue, Madison, WI, USA.
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Bodaleo F, Tapia-Monsalves C, Cea-Del Rio C, Gonzalez-Billault C, Nunez-Parra A. Structural and Functional Abnormalities in the Olfactory System of Fragile X Syndrome Models. Front Mol Neurosci 2019; 12:135. [PMID: 31191246 PMCID: PMC6548058 DOI: 10.3389/fnmol.2019.00135] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2019] [Accepted: 05/09/2019] [Indexed: 12/18/2022] Open
Abstract
Fragile X Syndrome (FXS) is the most common inherited form of intellectual disability. It is produced by mutation of the Fmr1 gene that encodes for the Fragile Mental Retardation Protein (FMRP), an important RNA-binding protein that regulates the expression of multiple proteins located in neuronal synapses. Individuals with FXS exhibit abnormal sensory information processing frequently leading to hypersensitivity across sensory modalities and consequently a wide array of behavioral symptoms. Insects and mammals engage primarily their sense of smell to create proper representations of the external world and guide adequate decision-making processes. This feature in combination with the exquisitely organized neuronal circuits found throughout the olfactory system (OS) and the wide expression of FMRP in brain regions that process olfactory information makes it an ideal model to study sensory alterations in FXS models. In the last decade several groups have taken advantage of these features and have used the OS of fruit fly and rodents to understand neuronal alteration giving rise to sensory perception issues. In this review article, we will discuss molecular, morphological and physiological aspects of the olfactory information processing in FXS models. We will highlight the decreased inhibitory/excitatory synaptic balance and the diminished synaptic plasticity found in this system resulting in behavioral alteration of individuals in the presence of odorant stimuli.
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Affiliation(s)
- Felipe Bodaleo
- Laboratory of Cellular and Neuronal Dynamics, Department of Biology, Faculty of Science, Universidad de Chile, Santiago, Chile.,Geroscience Center for Brain Health and Metabolism (GERO), Santiago, Chile
| | | | - Christian Cea-Del Rio
- Laboratory of Neurophysiopathology, Centro de Investigacion Biomedica y Aplicada (CIBAP), School of Medicine, Universidad de Santiago de Chile, Santiago, Chile
| | - Christian Gonzalez-Billault
- Laboratory of Cellular and Neuronal Dynamics, Department of Biology, Faculty of Science, Universidad de Chile, Santiago, Chile.,Geroscience Center for Brain Health and Metabolism (GERO), Santiago, Chile.,The Buck Institute for Research on Aging, Novato, CA, United States
| | - Alexia Nunez-Parra
- Department of Biology, Faculty of Science, Universidad de Chile, Santiago, Chile.,Cell Physiology Center, Universidad de Chile, Santiago, Chile
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Kinase pathway inhibition restores PSD95 induction in neurons lacking fragile X mental retardation protein. Proc Natl Acad Sci U S A 2019; 116:12007-12012. [PMID: 31118285 DOI: 10.1073/pnas.1812056116] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Fragile X syndrome (FXS) is the leading monogenic cause of autism and intellectual disability. FXS is caused by loss of expression of fragile X mental retardation protein (FMRP), an RNA-binding protein that regulates translation of numerous mRNA targets, some of which are present at synapses. While protein synthesis deficits have long been postulated as an etiology of FXS, how FMRP loss affects distributions of newly synthesized proteins is unknown. Here we investigated the role of FMRP in regulating expression of new copies of the synaptic protein PSD95 in an in vitro model of synaptic plasticity. We find that local BDNF application promotes persistent accumulation of new PSD95 at stimulated synapses and dendrites of cultured neurons, and that this accumulation is absent in FMRP-deficient mouse neurons. New PSD95 accumulation at sites of BDNF stimulation does not require known mechanisms regulating FMRP-mRNA interactions but instead requires the PI3K-mTORC1-S6K1 pathway. Surprisingly, in FMRP-deficient neurons, BDNF induction of new PSD95 accumulation can be restored by mTORC1-S6K1 blockade, suggesting that constitutively high mTORC1-S6K1 activity occludes PSD95 regulation by BDNF and that alternative pathways exist to mediate induction when mTORC1-S6K1 is inhibited. This study provides direct evidence for deficits in local protein synthesis and accumulation of newly synthesized protein in response to local stimulation in FXS, and supports mTORC1-S6K1 pathway inhibition as a potential therapeutic approach for FXS.
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FMRP - G-quadruplex mRNA - miR-125a interactions: Implications for miR-125a mediated translation regulation of PSD-95 mRNA. PLoS One 2019; 14:e0217275. [PMID: 31112584 PMCID: PMC6529005 DOI: 10.1371/journal.pone.0217275] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2019] [Accepted: 05/08/2019] [Indexed: 12/22/2022] Open
Abstract
Fragile X syndrome, the most common inherited form of intellectual disability, is caused by the CGG trinucleotide expansion in the 5'-untranslated region of the Fmr1 gene on the X chromosome, which silences the expression of the fragile X mental retardation protein (FMRP). FMRP has been shown to bind to a G-rich region within the PSD-95 mRNA, which encodes for the postsynaptic density protein 95, and together with microRNA-125a to mediate the reversible inhibition of the PSD-95 mRNA translation in neurons. The miR-125a binding site within the PSD-95 mRNA 3'-untranslated region (UTR) is embedded in a G-rich region bound by FMRP, which we have previously demonstrated folds into two parallel G-quadruplex structures. The FMRP regulation of PSD-95 mRNA translation is complex, being mediated by its phosphorylation. While the requirement for FMRP in the regulation of PSD-95 mRNA translation is clearly established, the exact mechanism by which this is achieved is not known. In this study, we have shown that both unphosphorylated FMRP and its phosphomimic FMRP S500D bind to the PSD-95 mRNA G-quadruplexes with high affinity, whereas only FMRP S500D binds to miR-125a. These results point towards a mechanism by which, depending on its phosphorylation status, FMRP acts as a switch that potentially controls the stability of the complex formed by the miR-125a-guided RNA induced silencing complex (RISC) and PSD-95 mRNA.
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Dulman RS, Auta J, Teppen T, Pandey SC. Acute Ethanol Produces Ataxia and Induces Fmr1 Expression via Histone Modifications in the Rat Cerebellum. Alcohol Clin Exp Res 2019; 43:1191-1198. [PMID: 30969437 DOI: 10.1111/acer.14044] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2018] [Accepted: 04/04/2019] [Indexed: 12/12/2022]
Abstract
BACKGROUND The cerebellum is fundamental for motor coordination and therefore crucial in ethanol (EtOH)-induced ataxia. EtOH contributes to cerebellar pathophysiology. Fragile-X mental retardation protein (FMRP) is a complex regulator of RNA and synaptic plasticity implicated in fragile-X tremor and ataxia syndrome, a phenotype featuring increased Fmr1 mRNA expression. Recent studies have implicated glutamatergic targets of FMRP in hereditary cerebellar ataxias including the main cerebellar excitatory amino acid (Eaa1) transporter and a subtype of metabotropic glutamate receptor (Grm5). However, EtOH-induced changes in cerebellar Fmr1 expression and its epigenetic regulation have not been investigated. Here, we examined the effects of acute EtOH exposure on ataxic behavior, gene expression, and epigenetic regulation of the Fmr1 gene and its glutamatergic targets in the rat cerebellum. METHODS Male adult Sprague Dawley rats received acute EtOH (2 g/kg) intraperitoneally 1 hour prior to ataxic behavioral testing on the accelerating rotarod and were sacrificed immediately thereafter. Cerebellar tissues were analyzed for gene expression and epigenetic regulation of the Fmr1 gene and its glutamatergic targets in the rat cerebellum using real-time quantitative polymerase chain reaction (PCR) and chromatin immunoprecipitation. RESULTS Acute EtOH exposure caused marked ataxia on the accelerating rotarod test compared with saline-treated controls. This ataxic response was associated with increases in mRNA levels of Fmr1, postsynaptic density 95 (Psd95), Eaa1, and Grm5 in the cerebellum. In addition, we found increased H3K27 acetylation both at the promoter region of Fmr1 and at a proposed cyclic adenosine monophosphate (cAMP) response-element binding (CREB) site downstream of the Fmr1 transcription start site. Furthermore, acute EtOH exposure significantly increased Creb1 and the histone acetyltransferases (HAT) CREB binding protein (Cbp), and p300 mRNA transcripts. CONCLUSIONS Overall, EtOH regulates cerebellar Fmr1 expression most likely via HAT-mediated increase in histone acetylation. We propose that FMRP regulation of glutamatergic transcripts plays an important role in disrupting the excitatory-inhibitory balance in the cerebellum underlying EtOH-induced ataxia.
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Affiliation(s)
- Russell S Dulman
- Department of Psychiatry, Center for Alcohol Research in Epigenetics, University of Illinois at Chicago, Chicago, Illinois
| | - James Auta
- Department of Psychiatry, Center for Alcohol Research in Epigenetics, University of Illinois at Chicago, Chicago, Illinois
| | - Tara Teppen
- Department of Psychiatry, Center for Alcohol Research in Epigenetics, University of Illinois at Chicago, Chicago, Illinois.,Jesse Brown Veterans Affairs Medical Center, Chicago, Illinois
| | - Subhash C Pandey
- Department of Psychiatry, Center for Alcohol Research in Epigenetics, University of Illinois at Chicago, Chicago, Illinois.,Department of Anatomy and Cell Biology, University of Illinois at Chicago, Chicago, Illinois.,Jesse Brown Veterans Affairs Medical Center, Chicago, Illinois
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Bagni C, Zukin RS. A Synaptic Perspective of Fragile X Syndrome and Autism Spectrum Disorders. Neuron 2019; 101:1070-1088. [PMID: 30897358 PMCID: PMC9628679 DOI: 10.1016/j.neuron.2019.02.041] [Citation(s) in RCA: 195] [Impact Index Per Article: 39.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2019] [Revised: 02/25/2019] [Accepted: 02/27/2019] [Indexed: 12/28/2022]
Abstract
Altered synaptic structure and function is a major hallmark of fragile X syndrome (FXS), autism spectrum disorders (ASDs), and other intellectual disabilities (IDs), which are therefore classified as synaptopathies. FXS and ASDs, while clinically and genetically distinct, share significant comorbidity, suggesting that there may be a common molecular and/or cellular basis, presumably at the synapse. In this article, we review brain architecture and synaptic pathways that are dysregulated in FXS and ASDs, including spine architecture, signaling in synaptic plasticity, local protein synthesis, (m)RNA modifications, and degradation. mRNA repression is a powerful mechanism for the regulation of synaptic structure and efficacy. We infer that there is no single pathway that explains most of the etiology and discuss new findings and the implications for future work directed at improving our understanding of the pathogenesis of FXS and related ASDs and the design of therapeutic strategies to ameliorate these disorders.
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Affiliation(s)
- Claudia Bagni
- Department of Fundamental Neurosciences, University of Lausanne, Lausanne, Switzerland; Department of Biomedicine and Prevention, University of Rome Tor Vergata, Rome, Italy.
| | - R Suzanne Zukin
- Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, New York City, NY, USA.
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Fazeli Z, Ghaderian SMH, Najmabadi H, Omrani MD. High expression of miR-510 was associated with CGG expansion located at upstream of FMR1 into full mutation. J Cell Biochem 2019; 120:1916-1923. [PMID: 30160796 DOI: 10.1002/jcb.27505] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2017] [Accepted: 08/20/2018] [Indexed: 01/24/2023]
Abstract
MicroRNAs (miRNAs) have been found to play an important role in the regulation of gene expression in eukaryotic organisms at the posttranscriptional level. More than half of miRNA genes have been recognized to be located in different fragile sites. Among them, miR-510 was located on chromosome X in the 27.3Xq region, flanking to a fragile X site. The CGG expansion and its methylation at the promoter of FMR1 located in this fragile site were associated with clinical symptoms of fragile X syndrome (FXS). The aim of the current study was to investigate whether the miR-510 expression was correlated with the CGG expansion of FMR1 in female carriers of full mutation. For this purpose, mesenchymal stem cells were isolated from peripheral blood of FMR1 full mutation female carriers. After differentiation of these cells into neuronal cells, the expression of miR-510 was analyzed by quantitative polymerase chain reaction. Furthermore, the target genes of miR-510 in the nervous system were also predicted by in silico method. The obtained results indicated that the CGG expansion of FMR1 was associated with the enhanced expression of miR-510. Furthermore, the bioinformatics analysis suggested that VHL and PPP2R5E genes could be considered as the most important target genes of miR-510 in the nervous system. This study showed that miR-510 and its target genes, specifically VHL and PPP2R5E, may represent the new targets for future therapy options of FXS.
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Affiliation(s)
- Zahra Fazeli
- Department of Medical Genetics, Faculty of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Sayyed Mohammad Hossein Ghaderian
- Department of Medical Genetics, Faculty of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran.,Urogenital Stem Cell Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Hossein Najmabadi
- Genetics Research Center, University of Social Welfare and Rehabilitation Sciences, Tehran, Iran
| | - Mir Davood Omrani
- Department of Medical Genetics, Faculty of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran.,Urogenital Stem Cell Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran
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45
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Kim S, Ham S, Yang K, Kim K. Protein kinase CK2 activation is required for transforming growth factor β-induced epithelial-mesenchymal transition. Mol Oncol 2018; 12:1811-1826. [PMID: 30171795 PMCID: PMC6165993 DOI: 10.1002/1878-0261.12378] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2017] [Revised: 07/29/2018] [Accepted: 08/16/2018] [Indexed: 12/22/2022] Open
Abstract
Transforming growth factor β (TGFβ) is overexpressed in advanced cancers and promotes tumorigenesis by inducing epithelial–mesenchymal transition (EMT), which enhances invasiveness and metastasis. Although we previously reported that EMT could be induced by increasing CK2 activity alone, it is not known whether CK2 also plays an essential role in TGFβ‐induced EMT. Therefore, in the present study, we investigated whether TGFβ signaling could activate CK2 and, if so, whether such activation is required for TGFβ‐induced EMT. We found that CK2 is activated by TGFβ treatment, and that activity peaks at 48 h after treatment. CK2 activation is dependent on TGFβ receptor (TGFBR) I kinase activity, but independent of SMAD4. Inhibition of CK2 activation through the use of either a CK2 inhibitor or shRNA against CSNK2A1 inhibited TGFβ‐induced EMT. TGFβ signaling decreased CK2β but did not affect CK2α protein levels, resulting in a quantitative imbalance between the catalytic α and regulatory β subunits, thereby increasing CK2 activity. The decrease in CK2β expression was dependent on TGFBRI kinase activity and the ubiquitin–proteasome pathway. The E3 ubiquitin ligases responsible for TGFβ‐induced CK2β degradation were found to be CHIP and WWP1. Okadaic acid (OA) pretreatment protected CK2β from TGFβ‐induced degradation, suggesting that dephosphorylation of CK2β by an OA‐sensitive phosphatase might be required for CK2 activation in TGFβ‐induced EMT. Collectively, our results suggest CK2 as a therapeutic target for the prevention of EMT and metastasis of cancers.
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Affiliation(s)
- Seongrak Kim
- Department of Biochemistry and Molecular Biology, Yonsei University College of Medicine, Seoul, Korea.,Integrated Genomic Research Center for Metabolic Regulation, Seoul, Korea
| | - Sunyoung Ham
- Quality Evaluation Team, Samsung Bioepis, Incheon, Korea
| | - Kyungmi Yang
- Department of Biochemistry and Molecular Biology, Yonsei University College of Medicine, Seoul, Korea
| | - Kunhong Kim
- Department of Biochemistry and Molecular Biology, Yonsei University College of Medicine, Seoul, Korea.,Integrated Genomic Research Center for Metabolic Regulation, Seoul, Korea
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46
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Haenfler JM, Skariah G, Rodriguez CM, Monteiro da Rocha A, Parent JM, Smith GD, Todd PK. Targeted Reactivation of FMR1 Transcription in Fragile X Syndrome Embryonic Stem Cells. Front Mol Neurosci 2018; 11:282. [PMID: 30158855 PMCID: PMC6104480 DOI: 10.3389/fnmol.2018.00282] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2018] [Accepted: 07/25/2018] [Indexed: 12/15/2022] Open
Abstract
Fragile X Syndrome (FXS) is the most common inherited cause of intellectual disability and autism. It results from expansion of a CGG nucleotide repeat in the 5′ untranslated region (UTR) of FMR1. Large expansions elicit repeat and promoter hyper-methylation, heterochromatin formation, FMR1 transcriptional silencing and loss of the Fragile X protein, FMRP. Efforts aimed at correcting the sequelae resultant from FMRP loss have thus far proven insufficient, perhaps because of FMRP’s pleiotropic functions. As the repeats do not disrupt the FMRP coding sequence, reactivation of endogenous FMR1 gene expression could correct the proximal event in FXS pathogenesis. Here we utilize the Clustered Regularly Interspaced Palindromic Repeats/deficient CRISPR associated protein 9 (CRISPR/dCas9) system to selectively re-activate transcription from the silenced FMR1 locus. Fusion of the transcriptional activator VP192 to dCas9 robustly enhances FMR1 transcription and increases FMRP levels when targeted directly to the CGG repeat in human cells. Using a previously uncharacterized FXS human embryonic stem cell (hESC) line which acquires transcriptional silencing with serial passaging, we achieved locus-specific transcriptional re-activation of FMR1 messenger RNA (mRNA) expression despite promoter and repeat methylation. However, these changes at the transcript level were not coupled with a significant elevation in FMRP protein expression in FXS cells. These studies demonstrate that directing a transcriptional activator to CGG repeats is sufficient to selectively reactivate FMR1 mRNA expression in Fragile X patient stem cells.
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Affiliation(s)
- Jill M Haenfler
- Department of Neurology, University of Michigan, Ann Arbor, MI, United States.,Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI, United States
| | - Geena Skariah
- Department of Neurology, University of Michigan, Ann Arbor, MI, United States
| | - Caitlin M Rodriguez
- Department of Neurology, University of Michigan, Ann Arbor, MI, United States
| | - Andre Monteiro da Rocha
- Department of Internal Medicine, Center for Arrhythmia Research, University of Michigan, Ann Arbor, MI, United States
| | - Jack M Parent
- Department of Neurology, University of Michigan, Ann Arbor, MI, United States.,Veterans Administration Ann Arbor Healthcare System, Ann Arbor, MI, United States
| | - Gary D Smith
- Departments of Obstetrics/Gynecology, Physiology, and Urology, University of Michigan, Ann Arbor, MI, United States
| | - Peter K Todd
- Department of Neurology, University of Michigan, Ann Arbor, MI, United States.,Veterans Administration Ann Arbor Healthcare System, Ann Arbor, MI, United States
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47
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Nayak T, Trotter J, Sakry D. The Intracellular Cleavage Product of the NG2 Proteoglycan Modulates Translation and Cell-Cycle Kinetics via Effects on mTORC1/FMRP Signaling. Front Cell Neurosci 2018; 12:231. [PMID: 30131676 PMCID: PMC6090502 DOI: 10.3389/fncel.2018.00231] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2018] [Accepted: 07/16/2018] [Indexed: 12/11/2022] Open
Abstract
The NG2 proteoglycan is expressed by oligodendrocyte precursor cells (OPCs) and is abundantly expressed by tumors such as melanoma and glioblastoma. Functions of NG2 include an influence on proliferation, migration and neuromodulation. Similar to other type-1 membrane proteins, NG2 undergoes proteolysis, generating a large ectodomain, a C-terminal fragment (CTF) and an intracellular domain (ICD) via sequential action of α- and γ-secretases which is enhanced by neuronal activity. Functional roles of NG2 have so far been shown for the full-length protein, the released ectodomain and CTF, but not for the ICD. In this study, we characterized the role of the NG2 ICD in OPC and Human Embryonic Kidney (HEK) cells. Overexpressed ICD is predominantly localized in the cell cytosol, including the distal processes of OPCs. Nuclear localisation of a fraction of the ICD is dependent on Nuclear Localisation Signals. Immunoprecipitation and Mass Spectrometry followed by functional analysis indicated that the NG2 ICD modulates mRNA translation and cell-cycle kinetics. In OPCs and HEK cells, ICD overexpression results in an mTORC1-dependent upregulation of translation, as well as a shift of the cell population toward S-phase. NG2 ICD increases the active (phosphorylated) form of mTOR and modulates downstream signaling cascades, including increased phosphorylation of p70S6K1 and increased expression of eEF2. Strikingly, levels of FMRP, an RNA-binding protein that is regulated by mTOR/p70S6K1/eEF2 were decreased. In neurons, FMRP acts as a translational repressor under activity-dependent control and is mutated in Fragile X Syndrome (FXS). Knock-down of endogenous NG2 in primary OPC reduced translation and mTOR/p70S6K1 phosphorylation in Oli-neu. Here, we identify the NG2 ICD as a regulator of translation in OPCs via modulation of the well-established mTORC1 pathway. We show that FXS-related FMRP signaling is not exclusive to neurons but plays a role in OPCs. This provides a signal cascade in OPC which can be influenced by the neuronal network, since the NG2 ICD has been shown to be generated by constitutive as well as activity-dependent cleavage. Our results also elucidate a possible role of NG2 in tumors exhibiting enhanced rates of translation and rapid cell cycle kinetics.
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Affiliation(s)
- Tanmoyita Nayak
- Department of Biology, Molecular Cell Biology, Institute of Developmental Biology and Neurobiology, Johannes Gutenberg University Mainz, Mainz, Germany
| | - Jacqueline Trotter
- Department of Biology, Molecular Cell Biology, Institute of Developmental Biology and Neurobiology, Johannes Gutenberg University Mainz, Mainz, Germany
| | - Dominik Sakry
- Department of Biology, Molecular Cell Biology, Institute of Developmental Biology and Neurobiology, Johannes Gutenberg University Mainz, Mainz, Germany.,Department of Molecular Neurobiology, Max Planck Institute for Experimental Medicine, Göttingen, Germany
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48
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Paradis-Isler N, Boehm J. NMDA receptor-dependent dephosphorylation of serine 387 in Argonaute 2 increases its degradation and affects dendritic spine density and maturation. J Biol Chem 2018; 293:9311-9325. [PMID: 29735530 DOI: 10.1074/jbc.ra117.001007] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2017] [Revised: 04/26/2018] [Indexed: 01/01/2023] Open
Abstract
Argonaute (AGO) proteins are essential components of the microRNA (miRNA) pathway. AGO proteins are loaded with miRNAs to target mRNAs and thereby regulate mRNA stability and protein translation. As such, AGO proteins are important actors in controlling local protein synthesis, for instance, at dendritic spines and synapses. Although miRNA-mediated regulation of dendritic mRNAs has become a focus of intense interest over the past years, the mechanisms regulating neuronal AGO proteins remain largely unknown. Here, using rat hippocampal neurons, we report that dendritic Ago2 is down-regulated by the proteasome upon NMDA receptor activation. We found that Ser-387 in Ago2 is dephosphorylated upon NMDA treatment and that this dephosphorylation precedes Ago2 degradation. Expressing Ser-387 phosphorylation-deficient or phosphomimetic Ago2 in neurons, we observed that this phosphorylation site is involved in modulating dendritic spine morphology and postsynaptic density protein 95 (PSD-95) expression in spines. Collectively, our results point toward a signaling pathway linking NMDA receptor-dependent Ago2 dephosphorylation and turnover to postsynaptic structural changes. They support a model in which NMDA receptor-mediated dephosphorylation of Ago2 and Ago2 turnover contributes to the de-repression of mRNAs involved in spine growth and maturation.
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Affiliation(s)
- Nicolas Paradis-Isler
- From the Département Neurosciences, Groupe de Recherche sur le Système Nerveux Central, Université de Montréal, Montréal, Québec H3T 1J4, Canada
| | - Jannic Boehm
- From the Département Neurosciences, Groupe de Recherche sur le Système Nerveux Central, Université de Montréal, Montréal, Québec H3T 1J4, Canada
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49
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Banerjee A, Ifrim MF, Valdez AN, Raj N, Bassell GJ. Aberrant RNA translation in fragile X syndrome: From FMRP mechanisms to emerging therapeutic strategies. Brain Res 2018; 1693:24-36. [PMID: 29653083 PMCID: PMC7377270 DOI: 10.1016/j.brainres.2018.04.008] [Citation(s) in RCA: 76] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2018] [Revised: 03/30/2018] [Accepted: 04/06/2018] [Indexed: 02/07/2023]
Abstract
Research in the past decades has unfolded the multifaceted role of Fragile X mental retardation protein (FMRP) and how its absence contributes to the pathophysiology of Fragile X syndrome (FXS). Excess signaling through group 1 metabotropic glutamate receptors is commonly observed in mouse models of FXS, which in part is attributed to dysregulated translation and downstream signaling. Considering the wide spectrum of cellular and physiologic functions that loss of FMRP can affect in general, it may be advantageous to pursue disease mechanism based treatments that directly target translational components or signaling factors that regulate protein synthesis. Various FMRP targets upstream and downstream of the translational machinery are therefore being investigated to further our understanding of the molecular mechanism of RNA and protein synthesis dysregulation in FXS as well as test their potential role as therapeutic interventions to alleviate FXS associated symptoms. In this review, we will broadly discuss recent advancements made towards understanding the role of FMRP in translation regulation, new pre-clinical animal models with FMRP targets located at different levels of the translational and signal transduction pathways for therapeutic intervention as well as future use of stem cells to model FXS associated phenotypes.
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Affiliation(s)
- Anwesha Banerjee
- Department of Cell Biology, Emory University School of Medicine, Atlanta, GA 30322, USA.
| | - Marius F Ifrim
- Department of Cell Biology, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - Arielle N Valdez
- Department of Cell Biology, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - Nisha Raj
- Department of Cell Biology, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - Gary J Bassell
- Department of Cell Biology, Emory University School of Medicine, Atlanta, GA 30322, USA; Department of Neurology, Emory University School of Medicine, Atlanta, GA 30322, USA.
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50
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Liu DC, Seimetz J, Lee KY, Kalsotra A, Chung HJ, Lu H, Tsai NP. Mdm2 mediates FMRP- and Gp1 mGluR-dependent protein translation and neural network activity. Hum Mol Genet 2018; 26:3895-3908. [PMID: 29016848 DOI: 10.1093/hmg/ddx276] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2016] [Accepted: 07/11/2017] [Indexed: 01/08/2023] Open
Abstract
Activating Group 1 (Gp1) metabotropic glutamate receptors (mGluRs), including mGluR1 and mGluR5, elicits translation-dependent neural plasticity mechanisms that are crucial to animal behavior and circuit development. Dysregulated Gp1 mGluR signaling has been observed in numerous neurological and psychiatric disorders. However, the molecular pathways underlying Gp1 mGluR-dependent plasticity mechanisms are complex and have been elusive. In this study, we identified a novel mechanism through which Gp1 mGluR mediates protein translation and neural plasticity. Using a multi-electrode array (MEA) recording system, we showed that activating Gp1 mGluR elevates neural network activity, as demonstrated by increased spontaneous spike frequency and burst activity. Importantly, we validated that elevating neural network activity requires protein translation and is dependent on fragile X mental retardation protein (FMRP), the protein that is deficient in the most common inherited form of mental retardation and autism, fragile X syndrome (FXS). In an effort to determine the mechanism by which FMRP mediates protein translation and neural network activity, we demonstrated that a ubiquitin E3 ligase, murine double minute-2 (Mdm2), is required for Gp1 mGluR-induced translation and neural network activity. Our data showed that Mdm2 acts as a translation suppressor, and FMRP is required for its ubiquitination and down-regulation upon Gp1 mGluR activation. These data revealed a novel mechanism by which Gp1 mGluR and FMRP mediate protein translation and neural network activity, potentially through de-repressing Mdm2. Our results also introduce an alternative way for understanding altered protein translation and brain circuit excitability associated with Gp1 mGluR in neurological diseases such as FXS.
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Affiliation(s)
- Dai-Chi Liu
- Department of Molecular and Integrative Physiology, School of Molecular and Cellular Biology.,Neuroscience Program
| | - Joseph Seimetz
- Department of Biochemistry, School of Molecular and Cellular Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Kwan Young Lee
- Department of Molecular and Integrative Physiology, School of Molecular and Cellular Biology
| | - Auinash Kalsotra
- Department of Biochemistry, School of Molecular and Cellular Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA.,Carl R.Woese Institute of Genomic Biology, University of Illinois, Champaign, IL 61801, USA
| | - Hee Jung Chung
- Department of Molecular and Integrative Physiology, School of Molecular and Cellular Biology.,Neuroscience Program.,Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Hua Lu
- Department of Biochemistry and Molecular Biology.,Tulane Cancer Center, Tulane University School of Medicine, New Orleans, LA 70112, USA
| | - Nien-Pei Tsai
- Department of Molecular and Integrative Physiology, School of Molecular and Cellular Biology.,Neuroscience Program.,Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
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