1
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Tarannum R, Mun G, Quddos F, Swanger SA, Steward O, Farris S. Dendritically localized RNAs are packaged as diversely composed Ribonucleoprotein particles with heterogeneous copy number states. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.07.13.603387. [PMID: 39071419 PMCID: PMC11275876 DOI: 10.1101/2024.07.13.603387] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/30/2024]
Abstract
Localization of mRNAs to dendrites is a fundamental mechanism by which neurons achieve spatiotemporal control of gene expression. Translationally repressed neuronal mRNA transport granules, also referred to as ribonuclear proteins (RNPs), have been shown to be trafficked as single or low copy number RNPs and as larger complexes with multiple copies and/or species of mRNAs. However, there is little evidence of either population in intact neuronal circuits. Using single molecule fluorescence in situ hybridization studies in the dendrites of adult rat and mouse hippocampus, we provide evidence that supports the existence of multi-transcript RNPs with the constituents varying in amounts for each RNA species. By competing-off fluorescently labeled probe with serial increases of unlabeled probe, we detected stepwise decreases in Arc RNP number and fluorescence intensity, suggesting Arc RNAs localize to dendrites in both low- and multiple-copy number RNPs. When probing for multiple mRNAs, we find that localized RNPs are heterogeneous in size and colocalization patterns that vary per RNA. Further, localized RNAs that are targeted by the same trans-acting element (FMRP) display greater levels of colocalization compared to an RNA not targeted by FMRP. Simultaneous visualization and assessment of colocalization using highly multiplexed imaging of a dozen mRNA species targeted by FMRP demonstrates that dendritic RNAs are mostly trafficked as heteromeric cargoes of multiple types of RNAs (at least one or more RNAs). Moreover, the composition of these RNA cargoes correlates with the abundance of the transcripts even after accounting for expression. Collectively, these results suggest that dendritic RNPs are packaged as heterogeneous co-assemblies of different mRNAs and that RNP contents may be driven, at least partially, by highly abundant dendritic RNAs; a model that favors efficiency over fine-tuned control for sustaining long-distance trafficking of thousands of messenger molecules.
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Affiliation(s)
- Renesa Tarannum
- Fralin Biomedical Research Institute at Virginia Tech Carilion, Center for Neurobiology Research, Roanoke, Virginia
- Translational Biology, Medicine & Health Graduate Program, Virginia Tech, Blacksburg, Virginia
| | - Grace Mun
- Fralin Biomedical Research Institute at Virginia Tech Carilion, Center for Neurobiology Research, Roanoke, Virginia
| | - Fatima Quddos
- Fralin Biomedical Research Institute at Virginia Tech Carilion, Center for Neurobiology Research, Roanoke, Virginia
- Translational Biology, Medicine & Health Graduate Program, Virginia Tech, Blacksburg, Virginia
| | - Sharon A. Swanger
- Fralin Biomedical Research Institute at Virginia Tech Carilion, Center for Neurobiology Research, Roanoke, Virginia
- Department of Biomedical Sciences & Pathobiology, Virginia-Maryland College of Veterinary Medicine, Virginia Tech, Blacksburg, Virginia
- Virginia Tech Carilion School of Medicine, Roanoke, Virginia
| | | | - Shannon Farris
- Fralin Biomedical Research Institute at Virginia Tech Carilion, Center for Neurobiology Research, Roanoke, Virginia
- Department of Biomedical Sciences & Pathobiology, Virginia-Maryland College of Veterinary Medicine, Virginia Tech, Blacksburg, Virginia
- Virginia Tech Carilion School of Medicine, Roanoke, Virginia
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2
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Moreira-Gomes T, Nóbrega C. From the disruption of RNA metabolism to the targeting of RNA-binding proteins: The case of polyglutamine spinocerebellar ataxias. J Neurochem 2024; 168:1442-1459. [PMID: 37990934 DOI: 10.1111/jnc.16010] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2023] [Revised: 10/04/2023] [Accepted: 11/03/2023] [Indexed: 11/23/2023]
Abstract
Polyglutamine spinocerebellar ataxias (PolyQ SCAs) represent a group of monogenetic diseases in which the expanded polyglutamine repeats give rise to a mutated protein. The abnormally expanded polyglutamine protein produces aggregates and toxic species, causing neuronal dysfunction and neuronal death. The main symptoms of these disorders include progressive ataxia, motor dysfunction, oculomotor impairment, and swallowing problems. Nowadays, the current treatments are restricted to symptomatic alleviation, and no existing therapeutic strategies can reduce or stop the disease progression. Even though the origin of these disorders has been associated with polyglutamine-induced toxicity, RNA toxicity has recently gained relevance in polyQ SCAs molecular pathogenesis. Therefore, the research's focus on RNA metabolism has been increasing, especially on RNA-binding proteins (RBPs). The present review summarizes RNA metabolism, exposing the different processes and the main RBPs involved. We also explore the mechanisms by which RBPs are dysregulated in PolyQ SCAs. Finally, possible therapies targeting the RNA metabolism are presented as strategies to reverse neuropathological anomalies and mitigate physical symptoms.
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Affiliation(s)
- Tiago Moreira-Gomes
- ABC-RI, Algarve Biomedical Center Research Institute, Faro, Portugal
- Faculdade de Medicina e Ciências Biomédicas, Universidade do Algarve, Faro, Portugal
- Doctoral Program in Biomedical Sciences, Faculdade de Medicina e Ciências Biomédicas, Universidade do Algarve, Faro, Portugal
| | - Clévio Nóbrega
- ABC-RI, Algarve Biomedical Center Research Institute, Faro, Portugal
- Faculdade de Medicina e Ciências Biomédicas, Universidade do Algarve, Faro, Portugal
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3
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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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4
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Mockett BG, Davies JWT, Mills ZB, Kweon DY, Abraham WC. Alpha-secretase inhibition impairs Group I metabotropic glutamate receptor-mediated protein synthesis, long-term potentiation and long-term depression. Philos Trans R Soc Lond B Biol Sci 2024; 379:20230481. [PMID: 38853546 DOI: 10.1098/rstb.2023.0481] [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: 12/22/2023] [Accepted: 04/12/2024] [Indexed: 06/11/2024] Open
Abstract
Group I metabotropic glutamate receptors (Gp1-mGluRs) exert a host of effects on cellular functions, including enhancement of protein synthesis and the associated facilitation of long-term potentiation (LTP) and induction of long-term depression (LTD). However, the complete cascades of events mediating these events are not fully understood. Gp1-mGluRs trigger α-secretase cleavage of amyloid precursor protein, producing soluble amyloid precursor protein-α (sAPPα), a known regulator of LTP. However, the α-cleavage of APP has not previously been linked to Gp1-mGluR's actions. Using rat hippocampal slices, we found that the α-secretase inhibitor tumour necrosis factor-alpha protease inhibitor-1, which inhibits both disintegrin and metalloprotease 10 (ADAM10) and 17 (ADAM17) activity, blocked or reduced the ability of the Gp1-mGluR agonist (R,S)-3,5-dihydroxyphenylglycine (DHPG) to stimulate protein synthesis, metaplastically prime future LTP and elicit sub-maximal LTD. In contrast, the specific ADAM10 antagonist GI254023X did not affect the regulation of plasticity, suggesting that ADAM17 but not ADAM10 is involved in mediating these effects of DHPG. However, neither drug affected LTD that was strongly induced by either high-concentration DHPG or paired-pulse synaptic stimulation. Our data suggest that moderate Gp1-mGluR activation triggers α-secretase sheddase activity targeting APP or other membrane-bound proteins as part of a more complex signalling cascade than previously envisioned. This article is part of a discussion meeting issue 'Long-term potentiation: 50 years on'.
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Affiliation(s)
- Bruce G Mockett
- Department of Psychology, Brain Health Research Centre, Aotearoa Brain Project, University of Otago , Dunedin 9054, New Zealand
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5
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Martin-Solana E, Carter SD, Donahue EK, Ning J, Glausier JR, Preisegger MA, Eisenman L, Joseph PN, Bouchet-Marquis C, Wu K, Mobini CL, Frantz AN, Puig S, Hampton CM, Kabbani N, Jensen GJ, Watkins SC, Deisseroth K, Fenno LE, Gold MS, Wills ZP, Burkewitz K, Das S, Freyberg Z. Ribosome-Associated Vesicles promote activity-dependent local translation. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.06.07.598007. [PMID: 38895376 PMCID: PMC11185778 DOI: 10.1101/2024.06.07.598007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/21/2024]
Abstract
Local protein synthesis in axons and dendrites underpins synaptic plasticity. However, the composition of the protein synthesis machinery in distal neuronal processes and the mechanisms for its activity-driven deployment to local translation sites remain unclear. Here, we employed cryo-electron tomography, volume electron microscopy, and live-cell imaging to identify Ribosome-Associated Vesicles (RAVs) as a dynamic platform for moving ribosomes to distal processes. Stimulation via chemically-induced long-term potentiation causes RAV accumulation in distal sites to drive local translation. We also demonstrate activity-driven changes in RAV generation and dynamics in vivo, identifying tubular ER shaping proteins in RAV biogenesis. Together, our work identifies a mechanism for ribosomal delivery to distal sites in neurons to promote activity-dependent local translation.
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Affiliation(s)
- Eva Martin-Solana
- Department of Psychiatry, University of Pittsburgh, Pittsburgh, PA, USA
| | - Stephen D. Carter
- MRC-University of Glasgow Centre for Virus Research, University of Glasgow, Glasgow, UK
| | - Eric K.F. Donahue
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, TN, USA
| | - Jiying Ning
- Department of Psychiatry, University of Pittsburgh, Pittsburgh, PA, USA
| | - Jill R. Glausier
- Department of Psychiatry, University of Pittsburgh, Pittsburgh, PA, USA
| | | | - Leanna Eisenman
- Department of Neurobiology, University of Pittsburgh, Pittsburgh, PA, USA
| | - Paul N. Joseph
- Department of Psychiatry, University of Pittsburgh, Pittsburgh, PA, USA
| | | | - Ken Wu
- Materials and Structural Analysis, Thermo Fisher Scientific, Hillsboro, OR, USA
| | | | - Amber N. Frantz
- Department of Psychiatry, University of Pittsburgh, Pittsburgh, PA, USA
| | - Stephanie Puig
- Department of Psychiatry, University of Massachusetts Chan Medical School, Worcester, MA, USA
| | - Cheri M. Hampton
- UES, Inc., Dayton, OH, USA
- Materials and Manufacturing Directorate, Air Force Research Laboratory, Wright-Patterson Air Force Base, Dayton, OH, USA
| | - Nadine Kabbani
- Interdisciplinary Program in Neuroscience, George Mason University, Fairfax, VA, USA
- School of Systems Biology, George Mason University, Fairfax, VA, USA
| | - Grant J. Jensen
- Department of Chemistry and Biochemistry, Brigham Young University, Provo, UT, USA
| | - Simon C. Watkins
- Department of Cell Biology, University of Pittsburgh, Pittsburgh, PA, USA
| | - Karl Deisseroth
- Department of Bioengineering, Stanford University, Stanford, CA, USA
- Department of Psychiatry and Behavioral Sciences, Stanford University, Stanford, CA, USA
- Howard Hughes Medical Institute, Stanford, CA, USA
| | - Lief E. Fenno
- Departments of Psychiatry and Neuroscience, University of Texas Austin Dell Medical School, Austin, TX, USA
| | - Michael S. Gold
- Department of Neurobiology, University of Pittsburgh, Pittsburgh, PA, USA
| | - Zachary P. Wills
- Department of Neurobiology, University of Pittsburgh, Pittsburgh, PA, USA
| | - Kristopher Burkewitz
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, TN, USA
| | - Sulagna Das
- Department of Cell Biology, Albert Einstein College of Medicine, NY
- Department of Cell Biology, Emory University, Atlanta, GA, USA
- Department of Human Genetics, Emory University, Atlanta, GA, USA
| | - Zachary Freyberg
- Department of Psychiatry, University of Pittsburgh, Pittsburgh, PA, USA
- Department of Cell Biology, University of Pittsburgh, Pittsburgh, PA, USA
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6
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Marshall GF, Fasol M, Davies FCJ, Le Seelleur M, Fernandez Alvarez A, Bennett-Ness C, Gonzalez-Sulser A, Abbott CM. Face-valid phenotypes in a mouse model of the most common mutation in EEF1A2-related neurodevelopmental disorder. Dis Model Mech 2024; 17:dmm050501. [PMID: 38179821 PMCID: PMC10855229 DOI: 10.1242/dmm.050501] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2023] [Accepted: 12/21/2023] [Indexed: 01/06/2024] Open
Abstract
De novo heterozygous missense mutations in EEF1A2, encoding neuromuscular translation-elongation factor eEF1A2, are associated with developmental and epileptic encephalopathies. We used CRISPR/Cas9 to recapitulate the most common mutation, E122K, in mice. Although E122K heterozygotes were not observed to have convulsive seizures, they exhibited frequent electrographic seizures and EEG abnormalities, transient early motor deficits and growth defects. Both E122K homozygotes and Eef1a2-null mice developed progressive motor abnormalities, with E122K homozygotes reaching humane endpoints by P31. The null phenotype is driven by progressive spinal neurodegeneration; however, no signs of neurodegeneration were observed in E122K homozygotes. The E122K protein was relatively stable in neurons yet highly unstable in skeletal myocytes, suggesting that the E122K/E122K phenotype is instead driven by loss of function in muscle. Nevertheless, motor abnormalities emerged far earlier in E122K homozygotes than in nulls, suggesting a toxic gain of function and/or a possible dominant-negative effect. This mouse model represents the first animal model of an EEF1A2 missense mutation with face-valid phenotypes and has provided mechanistic insights needed to inform rational treatment design.
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Affiliation(s)
- Grant F. Marshall
- Centre for Genomic & Experimental Medicine, MRC Institute of Genetics and Molecular Medicine, University of Edinburgh, Western General Hospital, Crewe Road, Edinburgh EH4 2XU, UK
- Simons Initiative for the Developing Brain, University of Edinburgh, Edinburgh EH8 9XD, UK
| | - Melissa Fasol
- Simons Initiative for the Developing Brain, University of Edinburgh, Edinburgh EH8 9XD, UK
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh EH8 9XD, UK
| | - Faith C. J. Davies
- Centre for Genomic & Experimental Medicine, MRC Institute of Genetics and Molecular Medicine, University of Edinburgh, Western General Hospital, Crewe Road, Edinburgh EH4 2XU, UK
- Simons Initiative for the Developing Brain, University of Edinburgh, Edinburgh EH8 9XD, UK
| | - Matthew Le Seelleur
- Centre for Genomic & Experimental Medicine, MRC Institute of Genetics and Molecular Medicine, University of Edinburgh, Western General Hospital, Crewe Road, Edinburgh EH4 2XU, UK
| | - Alejandra Fernandez Alvarez
- Centre for Genomic & Experimental Medicine, MRC Institute of Genetics and Molecular Medicine, University of Edinburgh, Western General Hospital, Crewe Road, Edinburgh EH4 2XU, UK
| | - Cavan Bennett-Ness
- Centre for Genomic & Experimental Medicine, MRC Institute of Genetics and Molecular Medicine, University of Edinburgh, Western General Hospital, Crewe Road, Edinburgh EH4 2XU, UK
| | - Alfredo Gonzalez-Sulser
- Simons Initiative for the Developing Brain, University of Edinburgh, Edinburgh EH8 9XD, UK
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh EH8 9XD, UK
| | - Catherine M. Abbott
- Centre for Genomic & Experimental Medicine, MRC Institute of Genetics and Molecular Medicine, University of Edinburgh, Western General Hospital, Crewe Road, Edinburgh EH4 2XU, UK
- Simons Initiative for the Developing Brain, University of Edinburgh, Edinburgh EH8 9XD, UK
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7
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Pelletier OB, Brunori G, Wang Y, Robishaw JD. Post-transcriptional regulation and subcellular localization of G-protein γ7 subunit: implications for striatal function and behavioral responses to cocaine. Front Neuroanat 2024; 18:1394659. [PMID: 38764487 PMCID: PMC11100332 DOI: 10.3389/fnana.2024.1394659] [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: 03/01/2024] [Accepted: 04/17/2024] [Indexed: 05/21/2024] Open
Abstract
The striatal D1 dopamine receptor (D1R) and A2a adenosine receptor (A2aR) signaling pathways play important roles in drug-related behaviors. These receptors activate the Golf protein comprised of a specific combination of αolfβ2γ7 subunits. During assembly, the γ7 subunit sets the cellular level of the Golf protein. In turn, the amount of Golf protein determines the collective output from both D1R and A2aR signaling pathways. This study shows the Gng7 gene encodes multiple γ7 transcripts differing only in their non-coding regions. In striatum, Transcript 1 is the predominant isoform. Preferentially expressed in the neuropil, Transcript 1 is localized in dendrites where it undergoes post-transcriptional regulation mediated by regulatory elements in its 3' untranslated region that contribute to translational suppression of the γ7 protein. Earlier studies on gene-targeted mice demonstrated loss of γ7 protein disrupts assembly of the Golf protein. In the current study, morphological analysis reveals the loss of the Golf protein is associated with altered dendritic morphology of medium spiny neurons. Finally, behavioral analysis of conditional knockout mice with cell-specific deletion of the γ7 protein in distinct populations of medium spiny neurons reveals differential roles of the Golf protein in mediating behavioral responses to cocaine. Altogether, these findings provide a better understanding of the regulation of γ7 protein expression, its impact on Golf function, and point to a new potential target and mechanisms for treating addiction and related disorders.
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Affiliation(s)
- Oliver B. Pelletier
- Department of Biomedical Science, Charles E. Schmidt College of Medicine, Florida Atlantic University, Boca Raton, FL, United States
| | - Gloria Brunori
- Department of Biomedical Science, Charles E. Schmidt College of Medicine, Florida Atlantic University, Boca Raton, FL, United States
| | - Yingcai Wang
- Department of Biomedical Science, Charles E. Schmidt College of Medicine, Florida Atlantic University, Boca Raton, FL, United States
| | - Janet D. Robishaw
- Department of Biomedical Science, Charles E. Schmidt College of Medicine, Florida Atlantic University, Boca Raton, FL, United States
- Department of Comparative, Diagnostic, and Population Medicine, College of Veterinary Medicine, University of Florida, Gainesville, FL, United States
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8
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Hacisuleyman E, Hale CR, Noble N, Luo JD, Fak JJ, Saito M, Chen J, Weissman JS, Darnell RB. Neuronal activity rapidly reprograms dendritic translation via eIF4G2:uORF binding. Nat Neurosci 2024; 27:822-835. [PMID: 38589584 PMCID: PMC11088998 DOI: 10.1038/s41593-024-01615-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2023] [Accepted: 03/05/2024] [Indexed: 04/10/2024]
Abstract
Learning and memory require activity-induced changes in dendritic translation, but which mRNAs are involved and how they are regulated are unclear. In this study, to monitor how depolarization impacts local dendritic biology, we employed a dendritically targeted proximity labeling approach followed by crosslinking immunoprecipitation, ribosome profiling and mass spectrometry. Depolarization of primary cortical neurons with KCl or the glutamate agonist DHPG caused rapid reprogramming of dendritic protein expression, where changes in dendritic mRNAs and proteins are weakly correlated. For a subset of pre-localized messages, depolarization increased the translation of upstream open reading frames (uORFs) and their downstream coding sequences, enabling localized production of proteins involved in long-term potentiation, cell signaling and energy metabolism. This activity-dependent translation was accompanied by the phosphorylation and recruitment of the non-canonical translation initiation factor eIF4G2, and the translated uORFs were sufficient to confer depolarization-induced, eIF4G2-dependent translational control. These studies uncovered an unanticipated mechanism by which activity-dependent uORF translational control by eIF4G2 couples activity to local dendritic remodeling.
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Affiliation(s)
- Ezgi Hacisuleyman
- Laboratory of Molecular Neuro-oncology, The Rockefeller University, New York, NY, USA.
| | - Caryn R Hale
- Laboratory of Molecular Neuro-oncology, The Rockefeller University, New York, NY, USA
- Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Natalie Noble
- Laboratory of Molecular Neuro-oncology, The Rockefeller University, New York, NY, USA
| | - Ji-Dung Luo
- Bioinformatics Resource Center, The Rockefeller University, New York, NY, USA
| | - John J Fak
- Laboratory of Molecular Neuro-oncology, The Rockefeller University, New York, NY, USA
| | - Misa Saito
- Laboratory of Molecular Neuro-oncology, The Rockefeller University, New York, NY, USA
| | - Jin Chen
- Department of Pharmacology and Cecil H. and Ida Green Center for Reproductive Biology Sciences, The University of Texas Southwestern Medical Center, Dallas, TX, USA
- Altos Labs, Bay Area Institute of Science, Redwood City, CA, USA
| | - Jonathan S Weissman
- Whitehead Institute for Biomedical Research, Cambridge, MA, USA.
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA, USA.
- Howard Hughes Medical Institute, Massachusetts Institute of Technology, Cambridge, MA, USA.
- David H. Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, MA, 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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9
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Wei M, Yang L, Su F, Liu Y, Zhao X, Luo L, Sun X, Liu S, Dong Z, Zhang Y, Shi YS, Liang J, Zhang C. ABHD6 drives endocytosis of AMPA receptors to regulate synaptic plasticity and learning flexibility. Prog Neurobiol 2024; 233:102559. [PMID: 38159878 DOI: 10.1016/j.pneurobio.2023.102559] [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: 06/23/2023] [Revised: 10/26/2023] [Accepted: 12/06/2023] [Indexed: 01/03/2024]
Abstract
Trafficking of α-Amino-3-hydroxy-5-methylisoxazole-4-propionic acid (AMPA) receptors (AMPARs), mediated by AMPAR interacting proteins, enabled neurons to maintain tuning capabilities at rest or active state. α/β-Hydrolase domain-containing 6 (ABHD6), an endocannabinoid hydrolase, was an AMPAR auxiliary subunit found to negatively regulate the surface delivery of AMPARs. While ABHD6 was found to prevent AMPAR tetramerization in endoplasmic reticulum, ABHD6 was also reported to localize at postsynaptic site. Yet, the role of ABHD6 interacting with AMPAR at postsynaptic site, and the physiological significance of ABHD6 regulating AMPAR trafficking remains elusive. Here, we generated the ABHD6 knockout (ABHD6KO) mice and found that deletion of ABHD6 selectively enhanced AMPAR-mediated basal synaptic responses and the surface expression of postsynaptic AMPARs. Furthermore, we found that loss of ABHD6 impaired hippocampal long-term depression (LTD) and synaptic downscaling in hippocampal synapses. AMPAR internalization assays revealed that ABHD6 was essential for neuronal activity-dependent endocytosis of surface AMPARs, which is independent of ABHD6's hydrolase activity. The defects of AMPAR endocytosis and LTD are expressed as deficits in learning flexibility in ABHD6KO mice. Collectively, we demonstrated that ABHD6 is an endocytic accessory protein promoting AMPAR endocytosis, thereby contributes to the formation of LTD, synaptic downscaling and reversal learning.
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Affiliation(s)
- Mengping Wei
- School of Basic Medical Sciences, Beijing Key Laboratory of Neural Regeneration and Repair, Advanced Innovation Center for Human Brain Protection, Capital Medical University, Beijing 100069, China; State Key Laboratory of Neurology and Oncology Drug Development, Nanjing 210000, Jiangsu, China; Chinese Institute for Brain Research, Beijing 102206, China.
| | - Lei Yang
- School of Basic Medical Sciences, Beijing Key Laboratory of Neural Regeneration and Repair, Advanced Innovation Center for Human Brain Protection, Capital Medical University, Beijing 100069, China; State Key Laboratory of Neurology and Oncology Drug Development, Nanjing 210000, Jiangsu, China; Chinese Institute for Brain Research, Beijing 102206, China
| | - Feng Su
- Peking-Tsinghua Center for Life Sciences, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing 100871, China
| | - Ying Liu
- CAS Key Laboratory of Mental Health, Institute of Psychology, Chinese Academy of Sciences, Beijing 100101, China; Department of Psychology, University of Chinese Academy of Sciences, Beijing 100101, China
| | - Xinyi Zhao
- School of Basic Medical Sciences, Beijing Key Laboratory of Neural Regeneration and Repair, Advanced Innovation Center for Human Brain Protection, Capital Medical University, Beijing 100069, China; State Key Laboratory of Neurology and Oncology Drug Development, Nanjing 210000, Jiangsu, China; Chinese Institute for Brain Research, Beijing 102206, China
| | - Lin Luo
- School of Basic Medical Sciences, Beijing Key Laboratory of Neural Regeneration and Repair, Advanced Innovation Center for Human Brain Protection, Capital Medical University, Beijing 100069, China; State Key Laboratory of Neurology and Oncology Drug Development, Nanjing 210000, Jiangsu, China; Chinese Institute for Brain Research, Beijing 102206, China
| | - Xinyue Sun
- School of Basic Medical Sciences, Beijing Key Laboratory of Neural Regeneration and Repair, Advanced Innovation Center for Human Brain Protection, Capital Medical University, Beijing 100069, China; State Key Laboratory of Neurology and Oncology Drug Development, Nanjing 210000, Jiangsu, China; Chinese Institute for Brain Research, Beijing 102206, China
| | - Sen Liu
- School of Basic Medical Sciences, Beijing Key Laboratory of Neural Regeneration and Repair, Advanced Innovation Center for Human Brain Protection, Capital Medical University, Beijing 100069, China; State Key Laboratory of Neurology and Oncology Drug Development, Nanjing 210000, Jiangsu, China; Chinese Institute for Brain Research, Beijing 102206, China
| | - Zhaoqi Dong
- School of Basic Medical Sciences, Beijing Key Laboratory of Neural Regeneration and Repair, Advanced Innovation Center for Human Brain Protection, Capital Medical University, Beijing 100069, China
| | - Yong Zhang
- Department of Neurobiology, School of Basic Medical Sciences and Neuroscience Research Institute, Key Lab for Neuroscience, Ministry of Education of China and National Health Commission of the PR China, IDG/McGovern Institute for Brain Research at PKU, Peking University, Beijing 100083, China
| | - Yun Stone Shi
- Ministry of Education Key Laboratory of Model Animal for Disease Study, Model Animal Research Center, Medical School, Nanjing University, Nanjing 210032, China
| | - Jing Liang
- CAS Key Laboratory of Mental Health, Institute of Psychology, Chinese Academy of Sciences, Beijing 100101, China; Department of Psychology, University of Chinese Academy of Sciences, Beijing 100101, China.
| | - Chen Zhang
- School of Basic Medical Sciences, Beijing Key Laboratory of Neural Regeneration and Repair, Advanced Innovation Center for Human Brain Protection, Capital Medical University, Beijing 100069, China; State Key Laboratory of Neurology and Oncology Drug Development, Nanjing 210000, Jiangsu, China; Chinese Institute for Brain Research, Beijing 102206, China.
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10
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Wu PY, Ji L, De Sanctis C, Francesconi A, Inglebert Y, McKinney RA. Loss of synaptopodin impairs mGluR5 and protein synthesis-dependent mGluR-LTD at CA3-CA1 synapses. PNAS NEXUS 2024; 3:pgae062. [PMID: 38384385 PMCID: PMC10879843 DOI: 10.1093/pnasnexus/pgae062] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/09/2023] [Accepted: 02/01/2024] [Indexed: 02/23/2024]
Abstract
Metabotropic glutamate receptor-dependent long-term depression (mGluR-LTD) is an important form of synaptic plasticity that occurs in many regions of the central nervous system and is the underlying mechanism for several learning paradigms. In the hippocampus, mGluR-LTD is manifested by the weakening of synaptic transmission and elimination of dendritic spines. Interestingly, not all spines respond or undergo plasticity equally in response to mGluR-LTD. A subset of dendritic spines containing synaptopodin (SP), an actin-associated protein is critical for mGluR-LTD and protects spines from elimination through mGluR1 activity. The precise cellular function of SP is still enigmatic and it is still unclear how SP contributes to the functional aspect of mGluR-LTD despite its modulation of the structural plasticity. In this study, we show that the lack of SP impairs mGluR-LTD by negatively affecting the mGluR5-dependent activity. Such impairment of mGluR5 activity is accompanied by a significant decrease of surface mGluR5 level in SP knockout (SPKO) mice. Intriguingly, the remaining mGluR-LTD becomes a protein synthesis-independent process in the SPKO and is mediated instead by endocannabinoid signaling. These data indicate that the postsynaptic protein SP can regulate the locus of expression of mGluR-LTD and provide insight into our understanding of spine/synapse-specific plasticity.
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Affiliation(s)
- Pei You Wu
- Department of Pharmacology and Therapeutics, McGill University, Montreal, QC H3G 1Y6, Canada
| | - Linjia Ji
- Department of Pharmacology and Therapeutics, McGill University, Montreal, QC H3G 1Y6, Canada
| | - Claudia De Sanctis
- Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, New York, NY 10461, USA
| | - Anna Francesconi
- Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, New York, NY 10461, USA
| | - Yanis Inglebert
- Department of Pharmacology and Therapeutics, McGill University, Montreal, QC H3G 1Y6, Canada
| | - R Anne McKinney
- Department of Pharmacology and Therapeutics, McGill University, Montreal, QC H3G 1Y6, Canada
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11
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Veeraraghavan P, Engmann AK, Hatch JJ, Itoh Y, Nguyen D, Addison T, Macklis JD. Dynamic subtype- and context-specific subcellular RNA regulation in growth cones of developing neurons of the cerebral cortex. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.09.24.559186. [PMID: 38328182 PMCID: PMC10849483 DOI: 10.1101/2023.09.24.559186] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/09/2024]
Abstract
Molecular mechanisms that cells employ to compartmentalize function via localization of function-specific RNA and translation are only partially elucidated. We investigate long-range projection neurons of the cerebral cortex as highly polarized exemplars to elucidate dynamic regulation of RNA localization, stability, and translation within growth cones (GCs), leading tips of growing axons. Comparison of GC-localized transcriptomes between two distinct subtypes of projection neurons- interhemispheric-callosal and corticothalamic- across developmental stages identifies both distinct and shared subcellular machinery, and intriguingly highlights enrichment of genes associated with neurodevelopmental and neuropsychiatric disorders. Developmental context-specific components of GC-localized transcriptomes identify known and novel potential regulators of distinct phases of circuit formation: long-distance growth, target area innervation, and synapse formation. Further, we investigate mechanisms by which transcripts are enriched and dynamically regulated in GCs, and identify GC-enriched motifs in 3' untranslated regions. As one example, we identify cytoplasmic adenylation element binding protein 4 (CPEB4), an RNA binding protein regulating localization and translation of mRNAs encoding molecular machinery important for axonal branching and complexity. We also identify RNA binding motif single stranded interacting protein 1 (RBMS1) as a dynamically expressed regulator of RNA stabilization that enables successful callosal circuit formation. Subtly aberrant associative and integrative cortical circuitry can profoundly affect cortical function, often causing neurodevelopmental and neuropsychiatric disorders. Elucidation of context-specific subcellular RNA regulation for GC- and soma-localized molecular controls over precise circuit development, maintenance, and function offers generalizable insights for other polarized cells, and might contribute substantially to understanding neurodevelopmental and behavioral-cognitive disorders and toward targeted therapeutics.
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Affiliation(s)
- Priya Veeraraghavan
- Department of Stem Cell and Regenerative Biology, and Center for Brain Science, Harvard University, Cambridge, MA, USA
| | - Anne K. Engmann
- Department of Stem Cell and Regenerative Biology, and Center for Brain Science, Harvard University, Cambridge, MA, USA
| | - John J. Hatch
- Department of Stem Cell and Regenerative Biology, and Center for Brain Science, Harvard University, Cambridge, MA, USA
| | - Yasuhiro Itoh
- Department of Stem Cell and Regenerative Biology, and Center for Brain Science, Harvard University, Cambridge, MA, USA
| | - Duane Nguyen
- Department of Stem Cell and Regenerative Biology, and Center for Brain Science, Harvard University, Cambridge, MA, USA
| | - Thomas Addison
- Department of Stem Cell and Regenerative Biology, and Center for Brain Science, Harvard University, Cambridge, MA, USA
| | - Jeffrey D. Macklis
- Department of Stem Cell and Regenerative Biology, and Center for Brain Science, Harvard University, Cambridge, MA, USA
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12
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Wong HHW, Watt AJ, Sjöström PJ. Synapse-specific burst coding sustained by local axonal translation. Neuron 2024; 112:264-276.e6. [PMID: 37944518 DOI: 10.1016/j.neuron.2023.10.011] [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: 06/05/2023] [Revised: 08/19/2023] [Accepted: 09/13/2023] [Indexed: 11/12/2023]
Abstract
Neurotransmission in the brain is unreliable, suggesting that high-frequency spike bursts rather than individual spikes carry the neural code. For instance, cortical pyramidal neurons rely on bursts in memory formation. Protein synthesis is another key factor in long-term synaptic plasticity and learning but is widely considered unnecessary for synaptic transmission. Here, however, we show that burst neurotransmission at synapses between neocortical layer 5 pyramidal cells depends on axonal protein synthesis linked to presynaptic NMDA receptors and mTOR. We localized protein synthesis to axons with laser axotomy and puromycylation live imaging. We whole-cell recorded connected neurons to reveal how translation sustained readily releasable vesicle pool size and replenishment rate. We live imaged axons and found sparsely docked RNA granules, suggesting synapse-specific regulation. In agreement, translation boosted neurotransmission onto excitatory but not inhibitory basket or Martinotti cells. Local axonal mRNA translation is thus a hitherto unappreciated principle for sustaining burst coding at specific synapse types.
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Affiliation(s)
- Hovy Ho-Wai Wong
- Centre for Research in Neuroscience, Brain Repair and Integrative Neuroscience Program, Department of Medicine, Department of Neurology and Neurosurgery, The Research Institute of the McGill University Health Centre, Montreal General Hospital, Montreal, QC H3G 1A4, Canada.
| | - Alanna J Watt
- Biology Department, McGill University, Montreal, QC H3G 0B1, Canada
| | - P Jesper Sjöström
- Centre for Research in Neuroscience, Brain Repair and Integrative Neuroscience Program, Department of Medicine, Department of Neurology and Neurosurgery, The Research Institute of the McGill University Health Centre, Montreal General Hospital, Montreal, QC H3G 1A4, Canada.
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13
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Park EH, Kao HY, Jourdi H, van Dijk MT, Carrillo-Segura S, Tunnell KW, Gutierrez J, Wallace EJ, Troy-Regier M, Radwan B, Lesburguères E, Alarcon JM, Fenton AA. Phencyclidine Disrupts Neural Coordination and Cognitive Control by Dysregulating Translation. BIOLOGICAL PSYCHIATRY GLOBAL OPEN SCIENCE 2024; 4:252-263. [PMID: 38298788 PMCID: PMC10829677 DOI: 10.1016/j.bpsgos.2023.04.009] [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: 12/09/2022] [Revised: 04/19/2023] [Accepted: 04/20/2023] [Indexed: 02/02/2024] Open
Abstract
Background Phencyclidine (PCP) causes psychosis, is abused with increasing frequency, and was extensively used in antipsychotic drug discovery. PCP discoordinates hippocampal ensemble action potential discharge and impairs cognitive control in rats, but how this uncompetitive NMDA receptor (NMDAR) antagonist impairs cognition remains unknown. Methods The effects of PCP were investigated on hippocampal CA1 ensemble action potential discharge in vivo in urethane-anesthetized rats and during awake behavior in mice, on synaptic responses in ex vivo mouse hippocampus slices, in mice on a hippocampus-dependent active place avoidance task that requires cognitive control, and on activating the molecular machinery of translation in acute hippocampus slices. Mechanistic causality was assessed by comparing the PCP effects with the effects of inhibitors of protein synthesis, group I metabotropic glutamate receptors (mGluR1/5), and subunit-selective NMDARs. Results Consistent with ionotropic actions, PCP discoordinated CA1 ensemble action potential discharge. PCP caused hyperactivity and impaired active place avoidance, despite the rodents having learned the task before PCP administration. Consistent with metabotropic actions, PCP exaggerated protein synthesis-dependent DHPG-induced mGluR1/5-stimulated long-term synaptic depression. Pretreatment with anisomycin or the mGluR1/5 antagonist MPEP, both of which repress translation, prevented PCP-induced discoordination and the cognitive and sensorimotor impairments. PCP as well as the NR2A-containing NMDAR antagonist NVP-AAM077 unbalanced translation that engages the Akt, mTOR (mechanistic target of rapamycin), and 4EBP1 translation machinery and increased protein synthesis, whereas the NR2B-containing antagonist Ro25-6981 did not. Conclusions PCP dysregulates translation, acting through NR2A-containing NMDAR subtypes, recruiting mGluR1/5 signaling pathways, and leading to neural discoordination that is central to the cognitive and sensorimotor impairments.
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Affiliation(s)
- Eun Hye Park
- Center for Neural Science, New York University, New York, New York
| | - Hsin-Yi Kao
- Center for Neural Science, New York University, New York, New York
| | - Hussam Jourdi
- Center for Neural Science, New York University, New York, New York
| | - Milenna T. van Dijk
- Center for Neural Science, New York University, New York, New York
- Graduate Program in Neuroscience and Physiology, New York University Langone Medical Center, New York, New York
| | - Simón Carrillo-Segura
- Center for Neural Science, New York University, New York, New York
- Graduate Program in Mechanical and Aerospace Engineering, New York University Tandon School of Engineering, New York, New York
| | - Kayla W. Tunnell
- Center for Neural Science, New York University, New York, New York
| | | | - Emma J. Wallace
- Graduate Program in Neural and Behavioral Science, State University of New York, Downstate Health Sciences University, Brooklyn, New York
- Department of Physiology and Pharmacology, State University of New York, Downstate Health Sciences University, Brooklyn, New York
| | - Matthew Troy-Regier
- Graduate Program in Neural and Behavioral Science, State University of New York, Downstate Health Sciences University, Brooklyn, New York
- Department of Physiology and Pharmacology, State University of New York, Downstate Health Sciences University, Brooklyn, New York
| | - Basma Radwan
- Graduate Program in Neural Science, Center for Neural Science, New York University, New York, New York
| | | | - Juan Marcos Alarcon
- Department of Pathology, State University of New York, Downstate Health Sciences University, Brooklyn, New York
- Robert F. Furchgott Center for Neural and Behavioral Science, State University of New York, Downstate Health Sciences University, Brooklyn, New York
| | - André A. Fenton
- Center for Neural Science, New York University, New York, New York
- Department of Physiology and Pharmacology, State University of New York, Downstate Health Sciences University, Brooklyn, New York
- Robert F. Furchgott Center for Neural and Behavioral Science, State University of New York, Downstate Health Sciences University, Brooklyn, New York
- Neuroscience Institute, NYU Langone Health, New York, New York
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14
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Ugalde MV, Alecki C, Rizwan J, Le P, Jacob-Tomas S, Xu JM, Minotti S, Wu T, Durham H, Yeo G. Localized molecular chaperone synthesis maintains neuronal dendrite proteostasis. RESEARCH SQUARE 2023:rs.3.rs-3673702. [PMID: 38168440 PMCID: PMC10760236 DOI: 10.21203/rs.3.rs-3673702/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2024]
Abstract
Proteostasis is maintained through regulated protein synthesis and degradation and chaperone-assisted protein folding. However, this is challenging in neuronal projections because of their polarized morphology and constant synaptic proteome remodeling. Using high-resolution fluorescence microscopy, we discovered that neurons localize a subset of chaperone mRNAs to their dendrites and use microtubule-based transport to increase this asymmetric localization following proteotoxic stress. The most abundant dendritic chaperone mRNA encodes a constitutive heat shock protein 70 family member (HSPA8). Proteotoxic stress also enhanced HSPA8 mRNA translation efficiency in dendrites. Stress-mediated HSPA8 mRNA localization to the dendrites was impaired by depleting fused in sarcoma-an amyotrophic lateral sclerosis-related protein-in cultured mouse motor neurons and expressing a pathogenic variant of heterogenous nuclear ribonucleoprotein A2/B1 in neurons derived from human induced pluripotent stem cells. These results reveal a crucial and unexpected neuronal stress response in which RNA-binding proteins increase the dendritic localization of HSPA8 mRNA to maintain proteostasis and prevent neurodegeneration.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | - Gene Yeo
- University of California, San Diego
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15
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Zou Z, Wei J, Chen Y, Kang Y, Shi H, Yang F, Shi Z, Chen S, Zhou Y, Sepich-Poore C, Zhuang X, Zhou X, Jiang H, Wen Z, Jin P, Luo C, He C. FMRP phosphorylation modulates neuronal translation through YTHDF1. Mol Cell 2023; 83:4304-4317.e8. [PMID: 37949069 PMCID: PMC10872974 DOI: 10.1016/j.molcel.2023.10.028] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2022] [Revised: 09/12/2023] [Accepted: 10/19/2023] [Indexed: 11/12/2023]
Abstract
RNA-binding proteins (RBPs) control messenger RNA fate in neurons. Here, we report a mechanism that the stimuli-induced neuronal translation is mediated by phosphorylation of a YTHDF1-binding protein FMRP. Mechanistically, YTHDF1 can condense with ribosomal proteins to promote the translation of its mRNA targets. FMRP regulates this process by sequestering YTHDF1 away from the ribosome; upon neuronal stimulation, FMRP becomes phosphorylated and releases YTHDF1 for translation upregulation. We show that a new small molecule inhibitor of YTHDF1 can reverse fragile X syndrome (FXS) developmental defects associated with FMRP deficiency in an organoid model. Our study thus reveals that FMRP and its phosphorylation are important regulators of activity-dependent translation during neuronal development and stimulation and identifies YTHDF1 as a potential therapeutic target for FXS in which developmental defects caused by FMRP depletion could be reversed through YTHDF1 inhibition.
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Affiliation(s)
- Zhongyu Zou
- Department of Chemistry, The University of Chicago, Chicago, IL 60637, USA; Howard Hughes Medical Institute, The University of Chicago, Chicago, IL 60637, USA
| | - Jiangbo Wei
- Department of Chemistry, The University of Chicago, Chicago, IL 60637, USA; Howard Hughes Medical Institute, The University of Chicago, Chicago, IL 60637, USA
| | - Yantao Chen
- The Center for Chemical Biology, Drug Discovery and Design Center, State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China
| | - Yunhee Kang
- Department of Psychiatry and Behavioral Sciences, Department of Cell Biology, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - Hailing Shi
- Department of Chemistry, The University of Chicago, Chicago, IL 60637, USA; Howard Hughes Medical Institute, The University of Chicago, Chicago, IL 60637, USA
| | - Fan Yang
- Department of Chemistry, The University of Chicago, Chicago, IL 60637, USA; Howard Hughes Medical Institute, The University of Chicago, Chicago, IL 60637, USA
| | - Zhuoyue Shi
- Department of Human Genetics, The University of Chicago, Chicago, IL 60637, USA
| | - Shijie Chen
- The Center for Chemical Biology, Drug Discovery and Design Center, State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China; School of Pharmaceutical Science and Technology, Hangzhou Institute for Advanced Study, UCAS, Hangzhou 310024, China
| | - Ying Zhou
- Department of Psychiatry and Behavioral Sciences, Department of Cell Biology, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - Caraline Sepich-Poore
- Howard Hughes Medical Institute, The University of Chicago, Chicago, IL 60637, USA; Medical Scientist Training Program, Department of Biochemistry and Molecular Biology, The University of Chicago, Chicago, IL 60637, USA
| | - Xiaoxi Zhuang
- Department of Neurobiology, The University of Chicago, Chicago, IL 60637, USA
| | - Xiaoming Zhou
- Department of Biochemistry, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75390, USA
| | - Hualiang Jiang
- The Center for Chemical Biology, Drug Discovery and Design Center, State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China
| | - Zhexing Wen
- Department of Psychiatry and Behavioral Sciences, Department of Cell Biology, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - Peng Jin
- Department of Psychiatry and Behavioral Sciences, Department of Cell Biology, Emory University School of Medicine, Atlanta, GA 30322, USA.
| | - Cheng Luo
- The Center for Chemical Biology, Drug Discovery and Design Center, State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China; School of Pharmaceutical Science and Technology, Hangzhou Institute for Advanced Study, UCAS, Hangzhou 310024, China; School of Pharmaceutical Sciences, Zhejiang Chinese Medical University, Hangzhou 310053, China.
| | - Chuan He
- Department of Chemistry, The University of Chicago, Chicago, IL 60637, USA; Howard Hughes Medical Institute, The University of Chicago, Chicago, IL 60637, USA.
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16
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Jung S, Shah S, Han G, Richter JD. FMRP deficiency leads to multifactorial dysregulation of splicing and mislocalization of MBNL1 to the cytoplasm. PLoS Biol 2023; 21:e3002417. [PMID: 38048343 PMCID: PMC10721184 DOI: 10.1371/journal.pbio.3002417] [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: 12/30/2022] [Revised: 12/14/2023] [Accepted: 11/03/2023] [Indexed: 12/06/2023] Open
Abstract
Fragile X syndrome (FXS) is a neurodevelopmental disorder that is often modeled in Fmr1 knockout mice where the RNA-binding protein FMRP is absent. Here, we show that in Fmr1-deficient mice, RNA mis-splicing occurs in several brain regions and peripheral tissues. To assess molecular mechanisms of splicing mis-regulation, we employed N2A cells depleted of Fmr1. In the absence of FMRP, RNA-specific exon skipping events are linked to the splicing factors hnRNPF, PTBP1, and MBNL1. FMRP regulates the translation of Mbnl1 mRNA as well as Mbnl1 RNA auto-splicing. Elevated Mbnl1 auto-splicing in FMRP-deficient cells results in the loss of a nuclear localization signal (NLS)-containing exon. This in turn alters the nucleus-to-cytoplasm ratio of MBNL1. This redistribution of MBNL1 isoforms in Fmr1-deficient cells could result in downstream splicing changes in other RNAs. Indeed, further investigation revealed that splicing disruptions resulting from Fmr1 depletion could be rescued by overexpression of nuclear MBNL1. Altered Mbnl1 auto-splicing also occurs in human FXS postmortem brain. These data suggest that FMRP-controlled translation and RNA processing may cascade into a general dys-regulation of splicing in Fmr1-deficient cells.
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Affiliation(s)
- Suna Jung
- Program in Molecular Medicine, University of Massachusetts Chan Medical School, Worcester, Massachusetts, United States of America
| | - Sneha Shah
- Program in Molecular Medicine, University of Massachusetts Chan Medical School, Worcester, Massachusetts, United States of America
| | - Geongoo Han
- Molecular Microbiology and Immunology, Brown University, Providence, Rhode Island, United States of America
| | - Joel D. Richter
- Program in Molecular Medicine, University of Massachusetts Chan Medical School, Worcester, Massachusetts, United States of America
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17
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Alecki C, Rizwan J, Le P, Jacob-Tomas S, Xu S, Minotti S, Wu T, Durham H, Yeo GW, Vera M. Localized synthesis of molecular chaperones sustains neuronal proteostasis. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.10.03.560761. [PMID: 37873158 PMCID: PMC10592939 DOI: 10.1101/2023.10.03.560761] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/25/2023]
Abstract
Neurons are challenged to maintain proteostasis in neuronal projections, particularly with the physiological stress at synapses to support intercellular communication underlying important functions such as memory and movement control. Proteostasis is maintained through regulated protein synthesis and degradation and chaperone-assisted protein folding. Using high-resolution fluorescent microscopy, we discovered that neurons localize a subset of chaperone mRNAs to their dendrites, particularly more proximal regions, and increase this asymmetric localization following proteotoxic stress through microtubule-based transport from the soma. The most abundant chaperone mRNA in dendrites encodes the constitutive heat shock protein 70, HSPA8. Proteotoxic stress in cultured neurons, induced by inhibiting proteasome activity or inducing oxidative stress, enhanced transport of Hspa8 mRNAs to dendrites and the percentage of mRNAs engaged in translation on mono and polyribosomes. Knocking down the ALS-related protein Fused in Sarcoma (FUS) and a dominant mutation in the heterogenous nuclear ribonucleoprotein A2/B1 (HNRNPA2B1) impaired stress-mediated localization of Hspa8 mRNA to dendrites in cultured murine motor neurons and human iPSC-derived neurons, respectively, revealing the importance of these RNA-binding proteins in maintaining proteostasis. These results reveal the increased dendritic localization and translation of the constitutive HSP70 Hspa8 mRNA as a crucial neuronal stress response to uphold proteostasis and prevent neurodegeneration.
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Affiliation(s)
- Celia Alecki
- Department of Biochemistry, McGill University, Montreal, Quebec H3G 1Y6, Canada
| | - Javeria Rizwan
- Department of Biochemistry, McGill University, Montreal, Quebec H3G 1Y6, Canada
| | - Phuong Le
- Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, CA, USA
| | - Suleima Jacob-Tomas
- Department of Biochemistry, McGill University, Montreal, Quebec H3G 1Y6, Canada
| | - Stella Xu
- Department of Biochemistry, McGill University, Montreal, Quebec H3G 1Y6, Canada
| | - Sandra Minotti
- Department of Neurology and Neurosurgery and Montreal Neurological Institute, McGill University, Montreal, Quebec H3A 2B4, Canada
| | - Tad Wu
- Department of Biochemistry, McGill University, Montreal, Quebec H3G 1Y6, Canada
| | - Heather Durham
- Department of Neurology and Neurosurgery and Montreal Neurological Institute, McGill University, Montreal, Quebec H3A 2B4, Canada
| | - Gene W Yeo
- Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, CA, USA
| | - Maria Vera
- Department of Biochemistry, McGill University, Montreal, Quebec H3G 1Y6, Canada
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18
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Alapin JM, Mohamed MS, Shrestha P, Khaled HG, Vorabyeva AG, Bowling HL, Oliveira MM, Klann E. Opto4E-BP, an optogenetic tool for inducible, reversible, and cell type-specific inhibition of translation initiation. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.08.30.554643. [PMID: 37693507 PMCID: PMC10491233 DOI: 10.1101/2023.08.30.554643] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/12/2023]
Abstract
The protein kinase mechanistic target of rapamycin complex 1 (mTORC1) is one of the primary triggers for initiating cap-dependent translation. Amongst its functions, mTORC1 phosphorylates eIF4E-binding proteins (4E-BPs), which prevents them from binding to eIF4E and thereby enables translation initiation. mTORC1 signaling is required for multiple forms of protein synthesis-dependent synaptic plasticity and various forms of long-term memory (LTM), including associative threat memory. However, the approaches used thus far to target mTORC1 and its effectors, such as pharmacological inhibitors or genetic knockouts, lack fine spatial and temporal control. The development of a conditional and inducible eIF4E knockdown mouse line partially solved the issue of spatial control, but still lacked optimal temporal control to study memory consolidation. Here, we have designed a novel optogenetic tool (Opto4E-BP) for cell type-specific, light-dependent regulation of eIF4E in the brain. We show that light-activation of Opto4E-BP decreases protein synthesis in HEK cells and primary mouse neurons. In situ , light-activation of Opto4E-BP in excitatory neurons decreased protein synthesis in acute amygdala slices. Finally, light activation of Opto4E-BP in principal excitatory neurons in the lateral amygdala (LA) of mice after training blocked the consolidation of LTM. The development of this novel optogenetic tool to modulate eIF4E-dependent translation with spatiotemporal precision will permit future studies to unravel the complex relationship between protein synthesis and the consolidation of LTM.
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19
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Wu PY, Ji L, De Sanctis C, Francesconi A, Inglebert Y, McKinney RA. Loss of synaptopodin impairs mGluR5 and protein synthesis dependent mGluR-LTD at CA3-CA1 synapses. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.08.02.551676. [PMID: 37577654 PMCID: PMC10418280 DOI: 10.1101/2023.08.02.551676] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/15/2023]
Abstract
Metabotropic glutamate receptor-dependent long-term depression (mGluR-LTD) is an important form of synaptic plasticity that occurs in many regions of the CNS and is the underlying mechanism for several learning paradigms. In the hippocampus, mGluR-LTD is manifested by the weakening of synaptic transmission and elimination of dendritic spines. Interestingly, not all spines respond or undergo plasticity equally in response to mGluR-LTD. A subset of dendritic spines containing synaptopodin (SP), an actin-associated protein, are critical for mGluR-LTD and protect spines from elimination through mGluR1 activity. The precise cellular function of SP is still enigmatic and it is still unclear how SP contributes to the functional aspect of mGluR-LTD despite of its modulation on the structural plasticity. In the present study, we show that the lack of SP impairs mGluR-LTD by negatively affecting the mGluR5-dependent activity. Such impairment of mGluR5 activity is accompanied by a significant decrease of surface mGluR5 level in SP knockout (SPKO) mice. Intriguingly, the remaining mGluR-LTD becomes a protein synthesis-independent process in the SPKO and is mediated instead by endocannabinoid signaling. These data show for the first time that the postsynaptic protein SP can regulate the locus of expression of mGluR-LTD and provide insight to our understanding of spine/synapse-specific plasticity. Significance statement Hippocampal group I metabotropic glutamate receptor dependent long-term depression (mGluR-LTD), a form of learning and memory, is misregulated in many murine models of neurodevelopmental disorders. Despite extensive studies there is a paucity of information on the molecular mechanism underlying mGluR-LTD. Previously, we reported that loss of synaptopodin, an actin-associated protein found in a subset of mature dendritic spines, impairs mGluR-LTD. In the current study, we uncover the molecular and cellular deficits involved. We find that synaptopodin is required for the mGluR5-Homer interaction and uncover synaptopodin as a molecular switch for mGluR-LTD expression, as mGluR-LTD becomes protein synthesis-independent and relies on endocannabinoid signaling in synaptopodin knock-out. This work provides insight into synaptopodin as a gatekeeper to regulate mGluR-LTD at hippocampal synapses.
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20
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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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21
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Huang YS, Mendez R, Fernandez M, Richter JD. CPEB and translational control by cytoplasmic polyadenylation: impact on synaptic plasticity, learning, and memory. Mol Psychiatry 2023; 28:2728-2736. [PMID: 37131078 PMCID: PMC10620108 DOI: 10.1038/s41380-023-02088-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/14/2023] [Revised: 04/18/2023] [Accepted: 04/19/2023] [Indexed: 05/04/2023]
Abstract
The late 1990s were banner years in molecular neuroscience; seminal studies demonstrated that local protein synthesis, at or near synapses, was necessary for synaptic plasticity, the underlying cellular basis of learning and memory [1, 2]. The newly made proteins were proposed to "tag" the stimulated synapse, distinguishing it from naive synapses, thereby forming a cellular memory [3]. Subsequent studies demonstrated that the transport of mRNAs from soma to dendrite was linked with translational unmasking at synapses upon synaptic stimulation. It soon became apparent that one prevalent mechanism governing these events is cytoplasmic polyadenylation, and that among the proteins that control this process, CPEB, plays a central role in synaptic plasticity, and learning and memory. In vertebrates, CPEB is a family of four proteins, all of which regulate translation in the brain, that have partially overlapping functions, but also have unique characteristics and RNA binding properties that make them control different aspects of higher cognitive function. Biochemical analysis of the vertebrate CPEBs demonstrate them to respond to different signaling pathways whose output leads to specific cellular responses. In addition, the different CPEBs, when their functions go awry, result in pathophysiological phenotypes resembling specific human neurological disorders. In this essay, we review key aspects of the vertebrate CPEB proteins and cytoplasmic polyadenylation within the context of brain function.
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Affiliation(s)
- Yi-Shuian Huang
- Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan.
| | - Raul Mendez
- Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology, 08028, Barcelona, Spain.
- Institució Catalana de Recerca i Estudis Avançats (ICREA), 08010, Barcelona, Spain.
| | | | - Joel D Richter
- Program in Molecular Medicine, University of Massachusetts Chan Medical School, Worcester, MA, 01605, USA.
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22
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Mango D, Ledonne A. Updates on the Physiopathology of Group I Metabotropic Glutamate Receptors (mGluRI)-Dependent Long-Term Depression. Cells 2023; 12:1588. [PMID: 37371058 DOI: 10.3390/cells12121588] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2023] [Revised: 06/01/2023] [Accepted: 06/05/2023] [Indexed: 06/29/2023] Open
Abstract
Group I metabotropic glutamate receptors (mGluRI), including mGluR1 and mGluR5 subtypes, modulate essential brain functions by affecting neuronal excitability, intracellular calcium dynamics, protein synthesis, dendritic spine formation, and synaptic transmission and plasticity. Nowadays, it is well appreciated that the mGluRI-dependent long-term depression (LTD) of glutamatergic synaptic transmission (mGluRI-LTD) is a key mechanism by which mGluRI shapes connectivity in various cerebral circuitries, directing complex brain functions and behaviors, and that it is deranged in several neurological and psychiatric illnesses, including neurodevelopmental disorders, neurodegenerative diseases, and psychopathologies. Here, we will provide an updated overview of the physiopathology of mGluRI-LTD, by describing mechanisms of induction and regulation by endogenous mGluRI interactors, as well as functional physiological implications and pathological deviations.
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Affiliation(s)
- Dalila Mango
- School of Pharmacy, University of Rome "Tor Vergata", 00133 Rome, Italy
- Laboratory of Pharmacology of Synaptic Plasticity, European Brain Research Institute, 00161 Rome, Italy
| | - Ada Ledonne
- Department of Systems Medicine, University of Rome "Tor Vergata", 00133 Rome, Italy
- Department of Experimental Neuroscience, IRCCS Fondazione Santa Lucia, 00143 Rome, Italy
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23
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Samadi M, Hales CA, Lustberg DJ, Farris S, Ross MR, Zhao M, Hepler JR, Harbin NH, Robinson ESJ, Banks PJ, Bashir ZI, Dudek SM. Mechanisms of mGluR-dependent plasticity in hippocampal area CA2. Hippocampus 2023; 33:730-744. [PMID: 36971428 PMCID: PMC10213158 DOI: 10.1002/hipo.23529] [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: 02/18/2023] [Revised: 03/04/2023] [Accepted: 03/08/2023] [Indexed: 03/29/2023]
Abstract
Pyramidal cells in hippocampal area CA2 have synaptic properties that are distinct from the other CA subregions. Notably, this includes a lack of typical long-term potentiation of stratum radiatum synapses. CA2 neurons express high levels of several known and potential regulators of metabotropic glutamate receptor (mGluR)-dependent signaling including Striatal-Enriched Tyrosine Phosphatase (STEP) and several Regulator of G-protein Signaling (RGS) proteins, yet the functions of these proteins in regulating mGluR-dependent synaptic plasticity in CA2 are completely unknown. Thus, the aim of this study was to examine mGluR-dependent synaptic depression and to determine whether STEP and the RGS proteins RGS4 and RGS14 are involved. Using whole cell voltage-clamp recordings from mouse pyramidal cells, we found that mGluR agonist-induced long-term depression (mGluR-LTD) is more pronounced in CA2 compared with that observed in CA1. This mGluR-LTD in CA2 was found to be protein synthesis and STEP dependent, suggesting that CA2 mGluR-LTD shares mechanistic processes with those seen in CA1, but in addition, RGS14, but not RGS4, was essential for mGluR-LTD in CA2. In addition, we found that exogenous application of STEP could rescue mGluR-LTD in RGS14 KO slices. Supporting a role for CA2 synaptic plasticity in social cognition, we found that RGS14 KO mice had impaired social recognition memory as assessed in a social discrimination task. These results highlight possible roles for mGluRs, RGS14, and STEP in CA2-dependent behaviors, perhaps by biasing the dominant form of synaptic plasticity away from LTP and toward LTD in CA2.
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Affiliation(s)
- Mahsa Samadi
- School of Physiology, Pharmacology and Neuroscience, Biomedical Sciences BuildingUniversity Walk, University of BristolBristolUKBS8 1TD
- Neurobiology Laboratory, National Institute of Environmental Health Sciences (NIH)111 T.W. Alexander Drive, Research Triangle ParkDurhamNorth Carolina27709USA
- Present address:
Faculty Education Office, Faculty of Medicine, Imperial College London, Hammersmith Campus, Wolfson Education CentreLondonUKW12 0NN
| | - Claire A. Hales
- School of Physiology, Pharmacology and Neuroscience, Biomedical Sciences BuildingUniversity Walk, University of BristolBristolUKBS8 1TD
- Present address:
Department of Psychology, Djavad Mowafaghian Centre for Brain HealthUniversity of British Columbia2215, Wesbrook MallVancouverBritish ColumbiaV6T 1Z3Canada
| | - Daniel J. Lustberg
- Neurobiology Laboratory, National Institute of Environmental Health Sciences (NIH)111 T.W. Alexander Drive, Research Triangle ParkDurhamNorth Carolina27709USA
- Present address:
Mouse Pharmacology GroupPsychogenics Inc215 College RoadParamusNew Jersey07652USA
| | - Shannon Farris
- Neurobiology Laboratory, National Institute of Environmental Health Sciences (NIH)111 T.W. Alexander Drive, Research Triangle ParkDurhamNorth Carolina27709USA
- Present address:
Fralin Biomedical Research Institute at Virginia TechRoanokeVirginia24014USA
| | - Madeleine R. Ross
- Neurobiology Laboratory, National Institute of Environmental Health Sciences (NIH)111 T.W. Alexander Drive, Research Triangle ParkDurhamNorth Carolina27709USA
| | - Meilan Zhao
- Neurobiology Laboratory, National Institute of Environmental Health Sciences (NIH)111 T.W. Alexander Drive, Research Triangle ParkDurhamNorth Carolina27709USA
| | - John R. Hepler
- Department of Pharmacology and Chemical BiologyEmory University School of Medicine100 Woodruff CircleAtlantaGeorgia30322USA
| | - Nicholas H. Harbin
- Department of Pharmacology and Chemical BiologyEmory University School of Medicine100 Woodruff CircleAtlantaGeorgia30322USA
| | - Emma S. J. Robinson
- School of Physiology, Pharmacology and Neuroscience, Biomedical Sciences BuildingUniversity Walk, University of BristolBristolUKBS8 1TD
| | - Paul J. Banks
- School of Physiology, Pharmacology and Neuroscience, Biomedical Sciences BuildingUniversity Walk, University of BristolBristolUKBS8 1TD
| | - Zafar I. Bashir
- School of Physiology, Pharmacology and Neuroscience, Biomedical Sciences BuildingUniversity Walk, University of BristolBristolUKBS8 1TD
| | - Serena M. Dudek
- Neurobiology Laboratory, National Institute of Environmental Health Sciences (NIH)111 T.W. Alexander Drive, Research Triangle ParkDurhamNorth Carolina27709USA
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24
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Malakasis N, Chavlis S, Poirazi P. Synaptic turnover promotes efficient learning in bio-realistic spiking neural networks. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.05.22.541722. [PMID: 37292929 PMCID: PMC10245885 DOI: 10.1101/2023.05.22.541722] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
While artificial machine learning systems achieve superhuman performance in specific tasks such as language processing, image and video recognition, they do so use extremely large datasets and huge amounts of power. On the other hand, the brain remains superior in several cognitively challenging tasks while operating with the energy of a small lightbulb. We use a biologically constrained spiking neural network model to explore how the neural tissue achieves such high efficiency and assess its learning capacity on discrimination tasks. We found that synaptic turnover, a form of structural plasticity, which is the ability of the brain to form and eliminate synapses continuously, increases both the speed and the performance of our network on all tasks tested. Moreover, it allows accurate learning using a smaller number of examples. Importantly, these improvements are most significant under conditions of resource scarcity, such as when the number of trainable parameters is halved and when the task difficulty is increased. Our findings provide new insights into the mechanisms that underlie efficient learning in the brain and can inspire the development of more efficient and flexible machine learning algorithms.
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Affiliation(s)
- Nikos Malakasis
- School of Medicine, University of Crete, Heraklion 70013, Greece
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas, Heraklion 70013, Greece
| | - Spyridon Chavlis
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas, Heraklion 70013, Greece
| | - Panayiota Poirazi
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas, Heraklion 70013, Greece
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25
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Lockyer J, Reading A, Vicenzi S, Delandre C, Marshall O, Gasperini R, Foa L, Lin JY. Optogenetic inhibition of Gα signalling alters and regulates circuit functionality and early circuit formation. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.05.06.539674. [PMID: 37214843 PMCID: PMC10197587 DOI: 10.1101/2023.05.06.539674] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Optogenetic techniques provide genetically targeted, spatially and temporally precise approaches to correlate cellular activities and physiological outcomes. In the nervous system, G-protein-coupled receptors (GPCRs) have essential neuromodulatory functions through binding extracellular ligands to induce intracellular signaling cascades. In this work, we develop and validate a new optogenetic tool that disrupt Gαq signaling through membrane recruitment of a minimal Regulator of G-protein signaling (RGS) domain. This approach, Photo-induced Modulation of Gα protein - Inhibition of Gαq (PiGM-Iq), exhibited potent and selective inhibition of Gαq signaling. We alter the behavior of C. elegans and Drosophila with outcomes consistent with GPCR-Gαq disruption. PiGM-Iq also changes axon guidance in culture dorsal root ganglia neurons in response to serotonin. PiGM-Iq activation leads to developmental deficits in zebrafish embryos and larvae resulting in altered neuronal wiring and behavior. By altering the choice of minimal RGS domain, we also show that this approach is amenable to Gαi signaling.
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Affiliation(s)
- Jayde Lockyer
- Tasmanian School of Medicine, University of Tasmania, Tasmania, Australia
| | - Andrew Reading
- Tasmanian School of Medicine, University of Tasmania, Tasmania, Australia
| | - Silvia Vicenzi
- Tasmanian School of Medicine, University of Tasmania, Tasmania, Australia
- Current affiliation, Moores Cancer Center, School of Medicine, Division of Regenerative Medicine, University of California, San Diego, California, USA
| | - Caroline Delandre
- Menzies Institute of Medical Research, University of Tasmania, Tasmania, Australia
| | - Owen Marshall
- Menzies Institute of Medical Research, University of Tasmania, Tasmania, Australia
| | - Robert Gasperini
- Tasmanian School of Medicine, University of Tasmania, Tasmania, Australia
| | - Lisa Foa
- School of Psychological Sciences, University of Tasmania, Tasmania, Australia
| | - John Y. Lin
- Tasmanian School of Medicine, University of Tasmania, Tasmania, Australia
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26
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Hirose T, Ninomiya K, Nakagawa S, Yamazaki T. A guide to membraneless organelles and their various roles in gene regulation. Nat Rev Mol Cell Biol 2023; 24:288-304. [PMID: 36424481 DOI: 10.1038/s41580-022-00558-8] [Citation(s) in RCA: 106] [Impact Index Per Article: 106.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/21/2022] [Indexed: 11/25/2022]
Abstract
Membraneless organelles (MLOs) are detected in cells as dots of mesoscopic size. By undergoing phase separation into a liquid-like or gel-like phase, MLOs contribute to intracellular compartmentalization of specific biological functions. In eukaryotes, dozens of MLOs have been identified, including the nucleolus, Cajal bodies, nuclear speckles, paraspeckles, promyelocytic leukaemia protein (PML) nuclear bodies, nuclear stress bodies, processing bodies (P bodies) and stress granules. MLOs contain specific proteins, of which many possess intrinsically disordered regions (IDRs), and nucleic acids, mainly RNA. Many MLOs contribute to gene regulation by different mechanisms. Through sequestration of specific factors, MLOs promote biochemical reactions by simultaneously concentrating substrates and enzymes, and/or suppressing the activity of the sequestered factors elsewhere in the cell. Other MLOs construct inter-chromosomal hubs by associating with multiple loci, thereby contributing to the biogenesis of macromolecular machineries essential for gene expression, such as ribosomes and spliceosomes. The organization of many MLOs includes layers, which might have different biophysical properties and functions. MLOs are functionally interconnected and are involved in various diseases, prompting the emergence of therapeutics targeting them. In this Review, we introduce MLOs that are relevant to gene regulation and discuss their assembly, internal structure, gene-regulatory roles in transcription, RNA processing and translation, particularly in stress conditions, and their disease relevance.
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Affiliation(s)
- Tetsuro Hirose
- Graduate School of Frontier Biosciences, Osaka University, Suita, Japan.
- Institute for Open and Transdisciplinary Research Initiatives, Osaka University, Suita, Japan.
| | - Kensuke Ninomiya
- Graduate School of Frontier Biosciences, Osaka University, Suita, Japan
| | - Shinichi Nakagawa
- Faculty of Pharmaceutical Sciences, Hokkaido University, Sapporo, Japan
| | - Tomohiro Yamazaki
- Graduate School of Frontier Biosciences, Osaka University, Suita, Japan
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27
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Valdivia G, Ardiles AO, Idowu A, Salazar C, Lee HK, Gallagher M, Palacios AG, Kirkwood A. mGluR-dependent plasticity in rodent models of Alzheimer's disease. Front Synaptic Neurosci 2023; 15:1123294. [PMID: 36937569 PMCID: PMC10017879 DOI: 10.3389/fnsyn.2023.1123294] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2022] [Accepted: 02/13/2023] [Indexed: 03/06/2023] Open
Abstract
Long-term potentiation (LTP) and depression (LTD) are currently the most comprehensive models of synaptic plasticity models to subserve learning and memory. In the CA1 region of the hippocampus LTP and LTD can be induced by the activation of either NMDA receptors or mGluR5 metabotropic glutamate receptors. Alterations in either form of synaptic plasticity, NMDAR-dependent or mGluR-dependent, are attractive candidates to contribute to learning deficits in conditions like Alzheimer's disease (AD) and aging. Research, however, has focused predominantly on NMDAR-dependent forms of LTP and LTD. Here we studied age-associated changes in mGluR-dependent LTP and LTD in the APP/PS1 mouse model of AD and in Octodon degu, a rodent model of aging that exhibits features of AD. At 2 months of age, APP/PS1 mouse exhibited robust mGluR-dependent LTP and LTD that was completely lost by the 8th month of age. The expression of mGluR protein in the hippocampus of APP/PS1 mice was not affected, consistent with previous findings indicating the uncoupling of the plasticity cascade from mGluR5 activation. In O. degu, the average mGluR-LTD magnitude is reduced by half by the 3 rd year of age. In aged O. degu individuals, the reduced mGluR-LTD correlated with reduced performance in a radial arm maze task. Altogether these findings support the idea that the preservation of mGluR-dependent synaptic plasticity is essential for the preservation of learning capacity during aging.
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Affiliation(s)
- Gonzalo Valdivia
- Mind/Brain Institute and Department of Neurosciences, Johns Hopkins University, Baltimore, MD, United States
- Centro Interdisciplinario de Neurociencia de Valparaíso, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso, Chile
| | - Alvaro O. Ardiles
- Centro Interdisciplinario de Neurociencia de Valparaíso, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso, Chile
| | - Abimbola Idowu
- Mind/Brain Institute and Department of Neurosciences, Johns Hopkins University, Baltimore, MD, United States
| | - Claudia Salazar
- Centro Interdisciplinario de Neurociencia de Valparaíso, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso, Chile
| | - Hey-Kyoung Lee
- Mind/Brain Institute and Department of Neurosciences, Johns Hopkins University, Baltimore, MD, United States
| | - Michela Gallagher
- Department of Psychological and Brain Sciences, Johns Hopkins University, Baltimore, MD, United States
| | - Adrian G. Palacios
- Centro Interdisciplinario de Neurociencia de Valparaíso, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso, Chile
| | - Alfredo Kirkwood
- Mind/Brain Institute and Department of Neurosciences, Johns Hopkins University, Baltimore, MD, United States
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28
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Li X, Jin DS, Eadara S, Caterina MJ, Meffert MK. Regulation by noncoding RNAs of local translation, injury responses, and pain in the peripheral nervous system. NEUROBIOLOGY OF PAIN (CAMBRIDGE, MASS.) 2023; 13:100119. [PMID: 36798094 PMCID: PMC9926024 DOI: 10.1016/j.ynpai.2023.100119] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/12/2022] [Revised: 01/17/2023] [Accepted: 01/21/2023] [Indexed: 06/18/2023]
Abstract
Neuropathic pain is a chronic condition arising from damage to somatosensory pathways that results in pathological hypersensitivity. Persistent pain can be viewed as a consequence of maladaptive plasticity which, like most enduring forms of cellular plasticity, requires altered expression of specific gene programs. Control of gene expression at the level of protein synthesis is broadly utilized to directly modulate changes in activity and responsiveness in nociceptive pathways and provides an effective mechanism for compartmentalized regulation of the proteome in peripheral nerves through local translation. Levels of noncoding RNAs (ncRNAs) are commonly impacted by peripheral nerve injury leading to persistent pain. NcRNAs exert spatiotemporal regulation of local proteomes and affect signaling cascades supporting altered sensory responses that contribute to hyperalgesia. This review discusses ncRNAs found in the peripheral nervous system (PNS) that are dysregulated following nerve injury and the current understanding of their roles in pathophysiological pain-related responses including neuroimmune interactions, neuronal survival and axon regeneration, Schwann cell dedifferentiation and proliferation, intercellular communication, and the generation of ectopic action potentials in primary afferents. We review progress in the field beyond cataloging, with a focus on the relevant target transcripts and mechanisms underlying pain modulation by ncRNAs.
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Affiliation(s)
- Xinbei Li
- Department of Biological Chemistry, Johns Hopkins University School of Medicine, United States
| | - Daniel S. Jin
- Department of Biological Chemistry, Johns Hopkins University School of Medicine, United States
| | - Sreenivas Eadara
- Department of Biological Chemistry, Johns Hopkins University School of Medicine, United States
| | - Michael J. Caterina
- Department of Biological Chemistry, Johns Hopkins University School of Medicine, United States
- Department of Neurosurgery and Neurosurgery Pain Research Institute, Johns Hopkins University School of Medicine, United States
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, United States
| | - Mollie K. Meffert
- Department of Biological Chemistry, Johns Hopkins University School of Medicine, United States
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, United States
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29
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Surdin T, Preissing B, Rohr L, Grömmke M, Böke H, Barcik M, Azimi Z, Jancke D, Herlitze S, Mark MD, Siveke I. Optogenetic activation of mGluR1 signaling in the cerebellum induces synaptic plasticity. iScience 2022; 26:105828. [PMID: 36632066 PMCID: PMC9826949 DOI: 10.1016/j.isci.2022.105828] [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: 04/12/2022] [Revised: 10/21/2022] [Accepted: 12/13/2022] [Indexed: 12/23/2022] Open
Abstract
Neuronal plasticity underlying cerebellar learning behavior is strongly associated with type 1 metabotropic glutamate receptor (mGluR1) signaling. Activation of mGluR1 leads to activation of the Gq/11 pathway, which is involved in inducing synaptic plasticity at the parallel fiber-Purkinje cell synapse (PF-PC) in form of long-term depression (LTD). To optogenetically modulate mGluR1 signaling we fused mouse melanopsin (OPN4) that activates the Gq/11 pathway to the C-termini of mGluR1 splice variants (OPN4-mGluR1a and OPN4-mGluR1b). Activation of both OPN4-mGluR1 variants showed robust Ca2+ increase in HEK cells and PCs of cerebellar slices. We provide the prove-of-concept approach to modulate synaptic plasticity via optogenetic activation of OPN4-mGluR1a inducing LTD at the PF-PC synapse in vitro. Moreover, we demonstrate that light activation of mGluR1a signaling pathway by OPN4-mGluR1a in PCs leads to an increase in intrinsic activity of PCs in vivo and improved cerebellum driven learning behavior.
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Affiliation(s)
- Tatjana Surdin
- Department of Zoology and Neurobiology, Ruhr-University Bochum, Bochum, Germany
| | - Bianca Preissing
- Department of Zoology and Neurobiology, Ruhr-University Bochum, Bochum, Germany
| | - Lennard Rohr
- Department of Zoology and Neurobiology, Ruhr-University Bochum, Bochum, Germany
| | - Michelle Grömmke
- Behavioral Neuroscience, Ruhr-University Bochum, Bochum, Germany
| | - Hanna Böke
- Department of Zoology and Neurobiology, Ruhr-University Bochum, Bochum, Germany
| | - Maike Barcik
- Cardiovascular Research Institute Düsseldorf, Division of Cardiology, Pulmonology, and Vascular Medicine, University Duesseldorf, Medical Faculty, Duesseldorf, Germany
| | - Zohre Azimi
- Optical Imaging Group, Institut für Neuroinformatik, Ruhr-University Bochum, Bochum, Germany
| | - Dirk Jancke
- Optical Imaging Group, Institut für Neuroinformatik, Ruhr-University Bochum, Bochum, Germany
| | - Stefan Herlitze
- Department of Zoology and Neurobiology, Ruhr-University Bochum, Bochum, Germany,Corresponding author
| | - Melanie D. Mark
- Behavioral Neuroscience, Ruhr-University Bochum, Bochum, Germany
| | - Ida Siveke
- Department of Zoology and Neurobiology, Ruhr-University Bochum, Bochum, Germany,Bridge Institute of Experimental Tumor Therapy, West German Cancer Center, University Hospital Essen, Essen, Germany,Corresponding author
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30
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Kawa AB, Hwang EK, Funke JR, Zhou H, Costa-Mattioli M, Wolf ME. Positive Allosteric Modulation of mGlu 1 Reverses Cocaine-Induced Behavioral and Synaptic Plasticity Through the Integrated Stress Response and Oligophrenin-1. Biol Psychiatry 2022; 92:871-879. [PMID: 35871097 PMCID: PMC10656746 DOI: 10.1016/j.biopsych.2022.05.008] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/20/2021] [Revised: 04/21/2022] [Accepted: 05/05/2022] [Indexed: 11/21/2022]
Abstract
BACKGROUND Cue-induced cocaine craving progressively intensifies (incubates) during abstinence from cocaine self-administration. Expression of incubated cocaine craving depends on elevated calcium-permeable AMPA receptors (CP-AMPARs) on medium spiny neurons in the nucleus accumbens (NAc) core. After incubation has occurred, stimulation of NAc metabotropic glutamate 1 (mGlu1) receptors or systemic administration of mGlu1 positive allosteric modulators removes CP-AMPARs from NAc synapses via dynamin-dependent internalization (mGlu1 long-term depression [LTD]) and thereby reduces incubated cocaine craving. Because mGlu1 positive allosteric modulators are potential therapeutics for cocaine craving, it is important to further define the mechanism triggering this mGlu1-LTD. METHODS Male and female rats self-administered saline or cocaine (10 days) using a long access regimen (6 h/day). Following ≥40 days of abstinence, we assessed the ability of an mGlu1 positive allosteric modulator to inhibit expression of incubated craving and remove CP-AMPARs from NAc synapses under control conditions, after blocking the integrated stress response (ISR), or after knocking down oligophrenin-1, a mediator of the ISR that can promote AMPAR endocytosis. AMPAR transmission in NAc medium spiny neurons was assessed with ex vivo slice recordings. RESULTS mGlu1 stimulation reduced cue-induced craving and removed synaptic CP-AMPARs. When the ISR was blocked prior to mGlu1 stimulation, there was no reduction in cue-induced craving, nor were CP-AMPARs removed from the synapse. Further, selective knockdown of oligophrenin-1 blocked mGlu1-LTD. CONCLUSIONS Our results indicate that mGlu1-LTD in the NAc and consequently the reduction of cue-induced seeking occur through activation of the ISR, which induces translation of oligophrenin-1. We also demonstrate CP-AMPAR accumulation and mGlu1 reversal in female rats, as previously shown in male rats.
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Affiliation(s)
- Alex B Kawa
- Department of Behavioral Neuroscience, Oregon Health & Science University, Portland, Oregon
| | - Eun-Kyung Hwang
- Department of Behavioral Neuroscience, Oregon Health & Science University, Portland, Oregon
| | - Jonathan R Funke
- Department of Behavioral Neuroscience, Oregon Health & Science University, Portland, Oregon
| | - Hongyi Zhou
- Department of Neuroscience, Baylor College of Medicine, Houston, Texas
| | | | - Marina E Wolf
- Department of Behavioral Neuroscience, Oregon Health & Science University, Portland, Oregon.
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31
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Zha C, Sossin WS. The molecular diversity of plasticity mechanisms underlying memory: An evolutionary perspective. J Neurochem 2022; 163:444-460. [PMID: 36326567 DOI: 10.1111/jnc.15717] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2022] [Revised: 08/29/2022] [Accepted: 10/17/2022] [Indexed: 11/06/2022]
Abstract
Experience triggers molecular cascades in organisms (learning) that lead to alterations (memory) to allow the organism to change its behavior based on experience. Understanding the molecular mechanisms underlying memory, particularly in the nervous system of animals, has been an exciting scientific challenge for neuroscience. We review what is known about forms of neuronal plasticity that underlie memory highlighting important issues in the field: (1) the importance of being able to measure how neurons are activated during learning to identify the form of plasticity that underlies memory, (2) the many distinct forms of plasticity important for memories that naturally decay both within and between organisms, and (3) unifying principles underlying the formation and maintenance of long-term memories. Overall, the diversity of molecular mechanisms underlying memories that naturally decay contrasts with more unified molecular mechanisms implicated in long-lasting changes. Despite many advances, important questions remain as to which mechanisms of neuronal plasticity underlie memory.
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Affiliation(s)
- Congyao Zha
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, Quebec, Canada
| | - Wayne S Sossin
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, Quebec, Canada
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32
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Argunşah AÖ, Erdil E, Ghani MU, Ramiro-Cortés Y, Hobbiss AF, Karayannis T, Çetin M, Israely I, Ünay D. An interactive time series image analysis software for dendritic spines. Sci Rep 2022; 12:12405. [PMID: 35859092 PMCID: PMC9300710 DOI: 10.1038/s41598-022-16137-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2022] [Accepted: 07/05/2022] [Indexed: 11/09/2022] Open
Abstract
Live fluorescence imaging has demonstrated the dynamic nature of dendritic spines, with changes in shape occurring both during development and in response to activity. The structure of a dendritic spine correlates with its functional efficacy. Learning and memory studies have shown that a great deal of the information stored by a neuron is contained in the synapses. High precision tracking of synaptic structures can give hints about the dynamic nature of memory and help us understand how memories evolve both in biological and artificial neural networks. Experiments that aim to investigate the dynamics behind the structural changes of dendritic spines require the collection and analysis of large time-series datasets. In this paper, we present an open-source software called SpineS for automatic longitudinal structural analysis of dendritic spines with additional features for manual intervention to ensure optimal analysis. We have tested the algorithm on in-vitro, in-vivo, and simulated datasets to demonstrate its performance in a wide range of possible experimental scenarios.
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Affiliation(s)
- Ali Özgür Argunşah
- Champalimaud Research, Champalimaud Centre for the Unknown, Lisbon, 1400-038, Portugal. .,Laboratory of Neural Circuit Assembly, Brain Research Institute (HiFo), University of Zürich, Zürich, Switzerland. .,UZH/ETH Zürich, Neuroscience Center Zurich (ZNZ), Zürich, Switzerland.
| | - Ertunç Erdil
- ETH Zürich, Computer Vision Laboratory, Zürich, Switzerland
| | - Muhammad Usman Ghani
- Department of Electrical and Computer Engineering, Boston University, Boston, 02215, MA, USA
| | - Yazmín Ramiro-Cortés
- Champalimaud Research, Champalimaud Centre for the Unknown, Lisbon, 1400-038, Portugal.,Departamento de Neurodesarrollo y Fisiología, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Mexico City, C.P. 04510, Mexico
| | - Anna F Hobbiss
- Champalimaud Research, Champalimaud Centre for the Unknown, Lisbon, 1400-038, Portugal
| | - Theofanis Karayannis
- Laboratory of Neural Circuit Assembly, Brain Research Institute (HiFo), University of Zürich, Zürich, Switzerland.,UZH/ETH Zürich, Neuroscience Center Zurich (ZNZ), Zürich, Switzerland
| | - Müjdat Çetin
- Department of Electrical and Computer Engineering, Goergen Institute for Data Science, University of Rochester, Rochester, 14627, NY, USA
| | - Inbal Israely
- Champalimaud Research, Champalimaud Centre for the Unknown, Lisbon, 1400-038, Portugal.,Department of Pathology and Cell Biology, Columbia University, New York, 10032, NY, USA
| | - Devrim Ünay
- Department of Biomedical Engineering, İzmir University of Economics, İzmir, Turkey. .,Department of Electrical and Electronics Engineering, İzmir Democracy University, İzmir, Turkey.
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33
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Seo SS, Louros SR, Anstey N, Gonzalez-Lozano MA, Harper CB, Verity NC, Dando O, Thomson SR, Darnell JC, Kind PC, Li KW, Osterweil EK. Excess ribosomal protein production unbalances translation in a model of Fragile X Syndrome. Nat Commun 2022; 13:3236. [PMID: 35688821 PMCID: PMC9187743 DOI: 10.1038/s41467-022-30979-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2021] [Accepted: 05/23/2022] [Indexed: 12/21/2022] Open
Abstract
Dysregulated protein synthesis is a core pathogenic mechanism in Fragile X Syndrome (FX). The mGluR Theory of FX predicts that pathological synaptic changes arise from the excessive translation of mRNAs downstream of mGlu1/5 activation. Here, we use a combination of CA1 pyramidal neuron-specific TRAP-seq and proteomics to identify the overtranslating mRNAs supporting exaggerated mGlu1/5 -induced long-term synaptic depression (mGluR-LTD) in the FX mouse model (Fmr1−/y). Our results identify a significant increase in the translation of ribosomal proteins (RPs) upon mGlu1/5 stimulation that coincides with a reduced translation of long mRNAs encoding synaptic proteins. These changes are mimicked and occluded in Fmr1−/y neurons. Inhibiting RP translation significantly impairs mGluR-LTD and prevents the length-dependent shift in the translating population. Together, these results suggest that pathological changes in FX result from a length-dependent alteration in the translating population that is supported by excessive RP translation. Dysregulated protein synthesis is key contributor to Fragile X syndrome. Here the authors identify a relationship between ribosome expression and the translation of long mRNAs that contributes to synaptic weakening in a model of Fragile X syndrome.
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Affiliation(s)
- Sang S Seo
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, UK.,Simons Initiative for the Developing Brain, University of Edinburgh, Edinburgh, UK
| | - Susana R Louros
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, UK.,Simons Initiative for the Developing Brain, University of Edinburgh, Edinburgh, UK
| | - Natasha Anstey
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, UK.,Simons Initiative for the Developing Brain, University of Edinburgh, Edinburgh, UK
| | - Miguel A Gonzalez-Lozano
- Department of Molecular and Cellular Neurobiology, Center for Neurogenomics and Cognitive Research, Vrije Universiteit Amsterdam, Amsterdam, Netherlands
| | - Callista B Harper
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, UK.,Simons Initiative for the Developing Brain, University of Edinburgh, Edinburgh, UK
| | - Nicholas C Verity
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, UK.,Simons Initiative for the Developing Brain, University of Edinburgh, Edinburgh, UK
| | - Owen Dando
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, UK.,Simons Initiative for the Developing Brain, University of Edinburgh, Edinburgh, UK
| | - Sophie R Thomson
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, UK.,Simons Initiative for the Developing Brain, University of Edinburgh, Edinburgh, UK
| | - Jennifer C Darnell
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, UK.,Simons Initiative for the Developing Brain, University of Edinburgh, Edinburgh, UK
| | - Peter C Kind
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, UK.,Simons Initiative for the Developing Brain, University of Edinburgh, Edinburgh, UK
| | - Ka Wan Li
- Department of Molecular and Cellular Neurobiology, Center for Neurogenomics and Cognitive Research, Vrije Universiteit Amsterdam, Amsterdam, Netherlands
| | - Emily K Osterweil
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, UK. .,Simons Initiative for the Developing Brain, University of Edinburgh, Edinburgh, UK.
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34
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Regulation and function of elF2B in neurological and metabolic disorders. Biosci Rep 2022; 42:231311. [PMID: 35579296 PMCID: PMC9208314 DOI: 10.1042/bsr20211699] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2021] [Revised: 04/28/2022] [Accepted: 05/12/2022] [Indexed: 11/27/2022] Open
Abstract
Eukaryotic initiation factor 2B, eIF2B is a guanine nucleotide exchange, factor with a central role in coordinating the initiation of translation. During stress and disease, the activity of eIF2B is inhibited via the phosphorylation of its substrate eIF2 (p-eIF2α). A number of different kinases respond to various stresses leading to the phosphorylation of the alpha subunit of eIF2, and collectively this regulation is known as the integrated stress response, ISR. This targeting of eIF2B allows the cell to regulate protein synthesis and reprogramme gene expression to restore homeostasis. Advances within structural biology have furthered our understanding of how eIF2B interacts with eIF2 in both the productive GEF active form and the non-productive eIF2α phosphorylated form. Here, current knowledge of the role of eIF2B in the ISR is discussed within the context of normal and disease states focusing particularly on diseases such as vanishing white matter disease (VWMD) and permanent neonatal diabetes mellitus (PNDM), which are directly linked to mutations in eIF2B. The role of eIF2B in synaptic plasticity and memory formation is also discussed. In addition, the cellular localisation of eIF2B is reviewed and considered along with the role of additional in vivo eIF2B binding factors and protein modifications that may play a role in modulating eIF2B activity during health and disease.
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35
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Asgarihafshejani A, Honoré È, Michon FX, Laplante I, Lacaille JC. Long-term potentiation at pyramidal cell to somatostatin interneuron synapses controls hippocampal network plasticity and memory. iScience 2022; 25:104259. [PMID: 35521524 PMCID: PMC9062215 DOI: 10.1016/j.isci.2022.104259] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2021] [Revised: 03/11/2022] [Accepted: 04/11/2022] [Indexed: 02/07/2023] Open
Abstract
Hippocampal somatostatin (SOM) cells are dendrite-projecting inhibitory interneurons. CA1 SOM cells receive major excitatory inputs from pyramidal cells (PC-SOM synapses) which show mGluR1a- and mTORC1-mediated long-term potentiation (LTP). PC-SOM synapse LTP contributes to CA1 network metaplasticity and memory consolidation, but whether it is sufficient to regulate these processes remains unknown. Here we used optogenetic stimulation of CA1 pyramidal cells and whole-cell recordings in slices to show that optogenetic theta-burst stimulation (TBSopto) produces LTP at PC-SOM synapses. At the network level, we found that TBSopto differentially regulates metaplasticity of pyramidal cell inputs: enhancing LTP at Schaffer collateral synapses and depressing LTP at temporo-ammonic synapses. At the behavioral level, we uncovered that in vivo TBSopto regulates learning-induced LTP at PC-SOM synapses, as well as contextual fear memory. Thus, LTP of PC-SOM synapses is a long-term feedback mechanism controlling pyramidal cell synaptic plasticity, sufficient to regulate memory consolidation. Optogenetic theta-burst (TBSopto) induces LTP at PC-SOM synapses TBSopto differentially regulates metaplasticity of pyramidal cell inputs In vivo TBSopto regulates PC-SOM plasticity and contextual fear memory PC-SOM synapse LTP grants durable feedback control of network plasticity and memory
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Affiliation(s)
- Azam Asgarihafshejani
- Department of Neurosciences, Center for Interdisciplinary Research on Brain and Learning (CIRCA) and Research Group on Neural Signaling and Circuitry (GRSNC), Université de Montréal, Montreal, Quebec H3C 3J7, Canada
| | - Ève Honoré
- Department of Neurosciences, Center for Interdisciplinary Research on Brain and Learning (CIRCA) and Research Group on Neural Signaling and Circuitry (GRSNC), Université de Montréal, Montreal, Quebec H3C 3J7, Canada
| | - François-Xavier Michon
- Department of Neurosciences, Center for Interdisciplinary Research on Brain and Learning (CIRCA) and Research Group on Neural Signaling and Circuitry (GRSNC), Université de Montréal, Montreal, Quebec H3C 3J7, Canada
| | - Isabel Laplante
- Department of Neurosciences, Center for Interdisciplinary Research on Brain and Learning (CIRCA) and Research Group on Neural Signaling and Circuitry (GRSNC), Université de Montréal, Montreal, Quebec H3C 3J7, Canada
| | - Jean-Claude Lacaille
- Department of Neurosciences, Center for Interdisciplinary Research on Brain and Learning (CIRCA) and Research Group on Neural Signaling and Circuitry (GRSNC), Université de Montréal, Montreal, Quebec H3C 3J7, Canada
- Corresponding author
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36
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Hobson BD, Kong L, Angelo MF, Lieberman OJ, Mosharov EV, Herzog E, Sulzer D, Sims PA. Subcellular and regional localization of mRNA translation in midbrain dopamine neurons. Cell Rep 2022; 38:110208. [PMID: 35021090 PMCID: PMC8844886 DOI: 10.1016/j.celrep.2021.110208] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2021] [Revised: 10/25/2021] [Accepted: 12/13/2021] [Indexed: 12/12/2022] Open
Abstract
Midbrain dopaminergic (mDA) neurons exhibit extensive dendritic and axonal arborizations, but local protein synthesis is not characterized in these neurons. Here, we investigate messenger RNA (mRNA) localization and translation in mDA neuronal axons and dendrites, both of which release dopamine (DA). Using highly sensitive ribosome-bound RNA sequencing and imaging approaches, we find no evidence for mRNA translation in mDA axons. In contrast, mDA neuronal dendrites in the substantia nigra pars reticulata (SNr) contain ribosomes and mRNAs encoding the major components of DA synthesis, release, and reuptake machinery. Surprisingly, we also observe dendritic localization of mRNAs encoding synaptic vesicle-related proteins, including those involved in exocytic fusion. Our results are consistent with a role for local translation in the regulation of DA release from dendrites, but not from axons. Our translatome data define a molecular signature of sparse mDA neurons in the SNr, including the enrichment of Atp2a3/SERCA3, an atypical ER calcium pump. Local translation regulates the subcellular proteome in neurons but has not been characterized in midbrain dopamine neurons, cells with large dendrites and axonal arborizations. Hobson et al. investigate messenger RNA localization and translation in midbrain dopamine neurons in the mouse brain, finding ribosomes and dopaminergic mRNAs in dendrites, but not axons.
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Affiliation(s)
- Benjamin D Hobson
- Department of Systems Biology, Columbia University Irving Medical Center, New York 10032, NY, USA; Medical Scientist Training Program, Columbia University Irving Medical Center, New York, NY 10032, USA; Department of Psychiatry, Columbia University Irving Medical Center, New York, NY 10032, USA
| | - Linghao Kong
- Department of Systems Biology, Columbia University Irving Medical Center, New York 10032, NY, USA
| | - Maria Florencia Angelo
- Interdisciplinary Institute for Neuroscience, Université de Bordeaux, Bordeaux, France; Interdisciplinary Institute for Neuroscience, CNRS UMR 5297, Bordeaux, France
| | - Ori J Lieberman
- Medical Scientist Training Program, Columbia University Irving Medical Center, New York, NY 10032, USA; Department of Psychiatry, Columbia University Irving Medical Center, New York, NY 10032, USA
| | - Eugene V Mosharov
- Department of Psychiatry, Columbia University Irving Medical Center, New York, NY 10032, USA; Division of Molecular Therapeutics, New York State Psychiatric Institute, New York, NY 10032, USA
| | - Etienne Herzog
- Interdisciplinary Institute for Neuroscience, Université de Bordeaux, Bordeaux, France; Interdisciplinary Institute for Neuroscience, CNRS UMR 5297, Bordeaux, France.
| | - David Sulzer
- Department of Neurology, Columbia University Irving Medical Center, New York, NY 10032, USA; Department of Psychiatry, Columbia University Irving Medical Center, New York, NY 10032, USA; Department of Pharmacology, Columbia University Irving Medical Center, New York, NY 10032, USA; Division of Molecular Therapeutics, New York State Psychiatric Institute, New York, NY 10032, USA; Aligning Science Across Parkinson's (ASAP) Collaborative Research Network, Chevy Chase, MD, USA.
| | - Peter A Sims
- Department of Systems Biology, Columbia University Irving Medical Center, New York 10032, NY, USA; Department of Biochemistry & Molecular Biophysics, Columbia University Irving Medical Center, New York, NY 10032, USA; Sulzberger Columbia Genome Center, Columbia University Irving Medical Center, New York, NY 10032, USA; Aligning Science Across Parkinson's (ASAP) Collaborative Research Network, Chevy Chase, MD, USA.
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37
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Liu X, Kumar V, Tsai NP, Auerbach BD. Hyperexcitability and Homeostasis in Fragile X Syndrome. Front Mol Neurosci 2022; 14:805929. [PMID: 35069112 PMCID: PMC8770333 DOI: 10.3389/fnmol.2021.805929] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2021] [Accepted: 12/14/2021] [Indexed: 01/13/2023] Open
Abstract
Fragile X Syndrome (FXS) is a leading inherited cause of autism and intellectual disability, resulting from a mutation in the FMR1 gene and subsequent loss of its protein product FMRP. Despite this simple genetic origin, FXS is a phenotypically complex disorder with a range of physical and neurocognitive disruptions. While numerous molecular and cellular pathways are affected by FMRP loss, there is growing evidence that circuit hyperexcitability may be a common convergence point that can account for many of the wide-ranging phenotypes seen in FXS. The mechanisms for hyperexcitability in FXS include alterations to excitatory synaptic function and connectivity, reduced inhibitory neuron activity, as well as changes to ion channel expression and conductance. However, understanding the impact of FMR1 mutation on circuit function is complicated by the inherent plasticity in neural circuits, which display an array of homeostatic mechanisms to maintain activity near set levels. FMRP is also an important regulator of activity-dependent plasticity in the brain, meaning that dysregulated plasticity can be both a cause and consequence of hyperexcitable networks in FXS. This makes it difficult to separate the direct effects of FMR1 mutation from the myriad and pleiotropic compensatory changes associated with it, both of which are likely to contribute to FXS pathophysiology. Here we will: (1) review evidence for hyperexcitability and homeostatic plasticity phenotypes in FXS models, focusing on similarities/differences across brain regions, cell-types, and developmental time points; (2) examine how excitability and plasticity disruptions interact with each other to ultimately contribute to circuit dysfunction in FXS; and (3) discuss how these synaptic and circuit deficits contribute to disease-relevant behavioral phenotypes like epilepsy and sensory hypersensitivity. Through this discussion of where the current field stands, we aim to introduce perspectives moving forward in FXS research.
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Affiliation(s)
- Xiaopeng Liu
- Deparment of Molecular & Integrative Physiology, University of Illinois at Urbana-Champaign, Urbana, IL, United States
- Beckman Institute for Advanced Science & Technology, University of Illinois at Urbana-Champaign, Urbana, IL, United States
| | - Vipendra Kumar
- Deparment of Molecular & Integrative Physiology, University of Illinois at Urbana-Champaign, Urbana, IL, United States
| | - Nien-Pei Tsai
- Deparment of Molecular & Integrative Physiology, University of Illinois at Urbana-Champaign, Urbana, IL, United States
| | - Benjamin D. Auerbach
- Deparment of Molecular & Integrative Physiology, University of Illinois at Urbana-Champaign, Urbana, IL, United States
- Beckman Institute for Advanced Science & Technology, University of Illinois at Urbana-Champaign, Urbana, IL, United States
- *Correspondence: Benjamin D. Auerbach
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38
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Hale CR, Sawicka K, Mora K, Fak JJ, Kang JJ, Cutrim P, Cialowicz K, Carroll TS, Darnell RB. FMRP regulates mRNAs encoding distinct functions in the cell body and dendrites of CA1 pyramidal neurons. eLife 2021; 10:71892. [PMID: 34939924 PMCID: PMC8820740 DOI: 10.7554/elife.71892] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2021] [Accepted: 12/13/2021] [Indexed: 12/02/2022] Open
Abstract
Neurons rely on translation of synaptic mRNAs in order to generate activity-dependent changes in plasticity. Here, we develop a strategy combining compartment-specific crosslinking immunoprecipitation (CLIP) and translating ribosome affinity purification (TRAP) in conditionally tagged mice to precisely define the ribosome-bound dendritic transcriptome of CA1 pyramidal neurons. We identify CA1 dendritic transcripts with differentially localized mRNA isoforms generated by alternative polyadenylation and alternative splicing, including many that have altered protein-coding capacity. Among dendritic mRNAs, FMRP targets were found to be overrepresented. Cell-type-specific FMRP-CLIP and TRAP in microdissected CA1 neuropil revealed 383 dendritic FMRP targets and suggests that FMRP differentially regulates functionally distinct modules in CA1 dendrites and cell bodies. FMRP regulates ~15–20% of mRNAs encoding synaptic functions and 10% of chromatin modulators, in the dendrite and cell body, respectively. In the absence of FMRP, dendritic FMRP targets had increased ribosome association, consistent with a function for FMRP in synaptic translational repression. Conversely, downregulation of FMRP targets involved in chromatin regulation in cell bodies suggests a role for FMRP in stabilizing mRNAs containing stalled ribosomes in this compartment. Together, the data support a model in which FMRP regulates the translation and expression of synaptic and nuclear proteins within different compartments of a single neuronal cell type. The brain has over 100 billion neurons that together form vast networks to relay electrical signals. A neuron receives electrical signals from other neurons via branch-like structures known as dendrites. The signals then travel into the cell body of the neuron. If their sum reaches a threshold, they fire a new signal through a single outgoing projection known as the axon, which is connected to the dendrites of other neurons. A single neuron has thousands of dendrites that each receive inputs from different axons, and it is thought that the strengthening and weakening of these dendritic connections enables us to learn and store memories. Dendrites are filled with molecules known as messenger ribonucleic acids (mRNAs) that act as templates to make proteins. Axonal signals reaching the dendrites can trigger these mRNAs to make new proteins that strengthen or weaken the connections between the two neurons, which is believed to be necessary for generating long-term memories. A protein called FMRP is found in both the cell body and dendrites and is able to bind to and regulate the ability of mRNAs to make proteins. A loss of the gene encoding FMRP is the most common cause of inherited intellectual disability and autism in humans, but it remains unclear precisely what role this protein plays in learning and memory. Hale et al. used genetic and bioinformatics approaches to specifically study mRNAs in the dendrites and the cell body of a specific type of neuron involved in memory in mice. The experiments revealed that FMRP played different roles in the dendrites and cell body. In the dendrites, FMRP interacted with mRNAs encoding proteins that can change how the neuron responds to a signal from a neighboring neuron and may alter how strong the connections between the neurons are. On the other hand, FMRP in the cell body modulated the activities of mRNAs encoding proteins that in turn regulate the activities of genes. These findings change the way we think about how memory may work by suggesting that groups of mRNAs encoding proteins with certain activities are found in distinct parts of a single neuron. These observations offer new ways to approach intellectual disabilities and autism spectrum disorder.
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Affiliation(s)
- Caryn R Hale
- Laboratory of Molecular Neuro-Oncology, Rockefeller University, New York, United States
| | - Kirsty Sawicka
- Laboratory of Molecular Neuro-Oncology, Rockefeller University, New York, United States
| | - Kevin Mora
- Laboratory of Molecular Neuro-Oncology, Rockefeller University, New York, United States
| | - John J Fak
- Laboratory of Molecular Neuro-Oncology, Rockefeller University, New York, United States
| | - Jin Joo Kang
- Laboratory of Molecular Neuro-Oncology, Rockefeller University, New York, United States
| | - Paula Cutrim
- Laboratory of Molecular Neuro-Oncology, Rockefeller University, New York, United States
| | - Katarzyna Cialowicz
- Bio-Imaging Resource Center, Rockefeller University, New York, United States
| | - Thomas S Carroll
- Bioinformatics Resouce Center, Rockefeller University, New York, United States
| | - Robert B Darnell
- Howard Hughes Medical Institute, Rockefeller University, New York, United States
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Membrane trafficking and positioning of mGluRs at presynaptic and postsynaptic sites of excitatory synapses. Neuropharmacology 2021; 200:108799. [PMID: 34592242 DOI: 10.1016/j.neuropharm.2021.108799] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2021] [Revised: 08/31/2021] [Accepted: 09/17/2021] [Indexed: 01/21/2023]
Abstract
The plethora of functions of glutamate in the brain are mediated by the complementary actions of ionotropic and metabotropic glutamate receptors (mGluRs). The ionotropic glutamate receptors carry most of the fast excitatory transmission, while mGluRs modulate transmission on longer timescales by triggering multiple intracellular signaling pathways. As such, mGluRs mediate critical aspects of synaptic transmission and plasticity. Interestingly, at synapses, mGluRs operate at both sides of the cleft, and thus bidirectionally exert the effects of glutamate. At postsynaptic sites, group I mGluRs act to modulate excitability and plasticity. At presynaptic sites, group II and III mGluRs act as auto-receptors, modulating release properties in an activity-dependent manner. Thus, synaptic mGluRs are essential signal integrators that functionally couple presynaptic and postsynaptic mechanisms of transmission and plasticity. Understanding how these receptors reach the membrane and are positioned relative to the presynaptic glutamate release site are therefore important aspects of synapse biology. In this review, we will discuss the currently known mechanisms underlying the trafficking and positioning of mGluRs at and around synapses, and how these mechanisms contribute to synaptic functioning. We will highlight outstanding questions and present an outlook on how recent technological developments will move this exciting research field forward.
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Ghasemi Z, Naderi N, Shojaei A, Raoufy MR, Ahmadirad N, Barkley V, Mirnajafi-Zadeh J. Group I metabotropic glutamate receptors contribute to the antiepileptic effect of electrical stimulation in hippocampal CA1 pyramidal neurons. Epilepsy Res 2021; 178:106821. [PMID: 34839145 DOI: 10.1016/j.eplepsyres.2021.106821] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Revised: 11/04/2021] [Accepted: 11/16/2021] [Indexed: 11/17/2022]
Abstract
Low-frequency deep brain stimulation (LFS) inhibits neuronal hyperexcitability during epilepsy. Accordingly, the use of LFS as a treatment method for patients with drug-resistant epilepsy has been proposed. However, the LFS antiepileptic mechanisms are not fully understood. Here, the role of metabotropic glutamate receptors group I (mGluR I) in LFS inhibitory action on epileptiform activity (EA) was investigated. EA was induced by increasing the K+ concentration in artificial cerebrospinal fluid (ACSF) up to 12 mM in hippocampal slices of male Wistar rats. LFS (1 Hz, 900 pulses) was delivered to the bundles of Schaffer collaterals at the beginning of EA. The excitability of CA1 pyramidal neurons was assayed by intracellular whole-cell recording. Applying LFS reduced the firing frequency during EA and substantially moved the membrane potential toward repolarization after a high-K+ ACSF washout. In addition, LFS attenuated the EA-generated neuronal hyperexcitability. A blockade of both mGluR 1 and mGluR 5 prevented the inhibitory action of LFS on EA-generated neuronal hyperexcitability. Activation of mGluR I mimicked the LFS effects and had similar inhibitory action on excitability of CA1 pyramidal neurons following EA. However, mGluR I agonist's antiepileptic action was not as strong as LFS. The observed LFS effects were significantly attenuated in the presence of a PKC inhibitor. Altogether, the LFS' inhibitory action on neuronal hyperexcitability following EA relies, in part, on the activity of mGluR I and a PKC-related signaling pathway.
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Affiliation(s)
- Zahra Ghasemi
- Department of Physiology, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran; Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, Canada
| | - Nima Naderi
- Department of Pharmacology and Toxicology, School of Pharmacy, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Amir Shojaei
- Department of Physiology, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran
| | - Mohammad Reza Raoufy
- Department of Physiology, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran
| | - Nooshin Ahmadirad
- Department of Physiology, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran
| | - Victoria Barkley
- Krembil Research Institute, University Health Network, Toronto, Canada
| | - Javad Mirnajafi-Zadeh
- Department of Physiology, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran; Institute for Brain Sciences and Cognition, Tarbiat Modares University, Tehran, Iran.
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Metaplastic Reinforcement of Long-Term Potentiation in Hippocampal Area CA2 by Cholinergic Receptor Activation. J Neurosci 2021; 41:9082-9098. [PMID: 34561235 DOI: 10.1523/jneurosci.2885-20.2021] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2020] [Revised: 09/13/2021] [Accepted: 09/18/2021] [Indexed: 11/21/2022] Open
Abstract
Hippocampal CA2, an inconspicuously positioned area between the well-studied CA1 and CA3 subfields, has captured research interest in recent years because of its role in social memory formation. However, the role of cholinergic inputs to the CA2 area for the regulation of synaptic plasticity remains to be fully understood. We show that cholinergic receptor activation with the nonselective cholinergic agonist, carbachol (CCh), triggers a protein synthesis-dependent and NMDAR-independent long-term synaptic depression (CCh-LTD) at entorhinal cortical (EC)-CA2 and Schaffer collateral (SC)-CA2 synapses in the hippocampus of adult male Wistar rats. The activation of muscarinic acetylcholine receptors (mAChRs) is critical for the induction of CCh-LTD with the results suggesting an involvement of M3 and M1 mAChRs in the early facilitation of CCh-LTD, while nicotinic AChR activation plays a role in the late maintenance of CCh-LTD at CA2 synapses. Remarkably, we find that CCh priming lowers the threshold for the subsequent induction of persistent long-term potentiation (LTP) of synaptic transmission at EC-CA2 and the plasticity-resistant SC-CA2 pathways. The effects of such a cholinergic-dependent synaptic depression on subsequent LTP at EC-CA2 and SC-CA2 synapses have not been previously explored. Collectively, the results demonstrate that CA2 synaptic learning rules are regulated in a metaplastic manner, whereby modifications triggered by prior cholinergic stimulation can dictate the outcome of future plasticity events. Moreover, the reinforcement of LTP at EC inputs to CA2 following the priming stimulus coexists with concurrent sustained CCh-LTD at the SC-CA2 pathway and is dynamically scaled by modulation of SC-CA2 synaptic transmission.SIGNIFICANCE STATEMENT The release of the neuromodulator acetylcholine is critically involved in processes of hippocampus-dependent memory formation. Cholinergic afferents originating in the medial septum and diagonal bands of Broca terminating in the hippocampal area CA2 might play an important role in the modulation of area-specific synaptic plasticity. Our findings demonstrate that cholinergic receptor activation induces an LTD of synaptic transmission at entorhinal cortical- and Schaffer collateral-CA2 synapses. This cholinergic activation-mediated LTD displays a bidirectional metaplastic switch to LTP on a future timescale. This suggests that such bidirectional synaptic modifications triggered by the dynamic modulation of tonic cholinergic receptor activation may support the formation of CA2-dependent memories given the increased hippocampal cholinergic tone during active wakefulness observed in exploratory behavior.
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Chalkiadaki K, Statoulla E, Markou M, Bellou S, Bagli E, Fotsis T, Murphy C, Gkogkas CG. Translational control in neurovascular brain development. ROYAL SOCIETY OPEN SCIENCE 2021; 8:211088. [PMID: 34659781 PMCID: PMC8511748 DOI: 10.1098/rsos.211088] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Accepted: 09/23/2021] [Indexed: 06/13/2023]
Abstract
The human brain carries out complex tasks and higher functions and is crucial for organismal survival, as it senses both intrinsic and extrinsic environments. Proper brain development relies on the orchestrated development of different precursor cells, which will give rise to the plethora of mature brain cell-types. Within this process, neuronal cells develop closely to and in coordination with vascular cells (endothelial cells (ECs), pericytes) in a bilateral communication process that relies on neuronal activity, attractive or repulsive guidance cues for both cell types and on tight-regulation of gene expression. Translational control is a master regulator of the gene-expression pathway and in particular for neuronal and ECs, it can be localized in developmentally relevant (axon growth cone, endothelial tip cell) and mature compartments (synapses, axons). Herein, we will review mechanisms of translational control relevant to brain development in neurons and ECs in health and disease.
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Affiliation(s)
- Kleanthi Chalkiadaki
- Division of Biomedical Research, Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas, University Campus, 45110 Ioannina, Greece
| | - Elpida Statoulla
- Division of Biomedical Research, Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas, University Campus, 45110 Ioannina, Greece
| | - Maria Markou
- Division of Biomedical Research, Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas, University Campus, 45110 Ioannina, Greece
| | - Sofia Bellou
- Division of Biomedical Research, Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas, University Campus, 45110 Ioannina, Greece
| | - Eleni Bagli
- Division of Biomedical Research, Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas, University Campus, 45110 Ioannina, Greece
| | - Theodore Fotsis
- Division of Biomedical Research, Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas, University Campus, 45110 Ioannina, Greece
| | - Carol Murphy
- Division of Biomedical Research, Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas, University Campus, 45110 Ioannina, Greece
| | - Christos G. Gkogkas
- Division of Biomedical Research, Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas, University Campus, 45110 Ioannina, Greece
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Cui F, Gu S, Gu Y, Yin J, Fang C, Liu L. Alteration in the mRNA expression profile of the autophagy-related mTOR pathway in schizophrenia patients treated with olanzapine. BMC Psychiatry 2021; 21:388. [PMID: 34348681 PMCID: PMC8335969 DOI: 10.1186/s12888-021-03394-w] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/18/2021] [Accepted: 07/26/2021] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The mammalian target of rapamycin protein (mTOR) signaling pathway is involved in the pathogenesis of schizophrenia and the mechanism of extrapyramidal adverse reactions to antipsychotic drugs, which might be mediated by an mTOR-dependent autophagy impairment. This study aimed to examine the expression of mTOR pathway genes in patients with schizophrenia treated with olanzapine, which is considered an mTOR inhibitor and autophagy inducer. METHODS Thirty-two patients with acute schizophrenia who had been treated with olanzapine for four weeks (average dose 14.24 ± 4.35 mg/d) and 32 healthy volunteers were recruited. Before and after olanzapine treatment, the Positive and Negative Syndrome Scale (PANSS) was used to evaluate the symptoms of patients with schizophrenia, and the mRNA expression levels of mTOR pathway-related genes, including MTOR, RICTOR, RAPTOR, and DEPTOR, were detected in fasting venous blood samples from all subjects using real-time quantitative PCR. RESULTS The MTOR and RICTOR mRNA expression levels in patients with acute schizophrenia were significantly decreased compared with those of healthy controls and further significantly decreased after four weeks of olanzapine treatment. The DEPTOR mRNA expression levels in patients with acute schizophrenia were not significantly different from those of healthy controls but were significantly increased after treatment. The expression levels of the RAPTOR mRNA were not significantly different among the three groups. The pairwise correlations of MTOR, DEPTOR, RAPTOR, and RICTOR mRNA expression levels in patients with acute schizophrenia and healthy controls were significant. After olanzapine treatment, the correlations between the expression levels of the DEPTOR and MTOR mRNAs and between the DEPTOR and RICTOR mRNAs disappeared. CONCLUSIONS Abnormalities in the mTOR pathway, especially DEPTOR and mTORC2, might play important roles in the autophagy mechanism underlying the pathophysiology of schizophrenia and effects of olanzapine treatment.
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Affiliation(s)
- Fengwei Cui
- grid.89957.3a0000 0000 9255 8984Department of Geriatric Psychiatry, Wuxi Mental Health Center, Nanjing Medical University, Wuxi, 214151 Jiangsu China
| | - Shuguang Gu
- grid.89957.3a0000 0000 9255 8984Department of Geriatric Psychiatry, Wuxi Mental Health Center, Nanjing Medical University, Wuxi, 214151 Jiangsu China
| | - Yue Gu
- grid.89957.3a0000 0000 9255 8984The First Clinical Medical College, Nanjing Medical University, Nanjing, 211166 Jiangsu China
| | - Jiajun Yin
- grid.89957.3a0000 0000 9255 8984Department of Geriatric Psychiatry, Wuxi Mental Health Center, Nanjing Medical University, Wuxi, 214151 Jiangsu China
| | - Chunxia Fang
- Combined TCM & Western Medicine Department, Wuxi Mental Health Center, Nanjing Medical University, Wuxi, 214151, Jiangsu, China.
| | - Liang Liu
- Department of Geriatric Psychiatry, Wuxi Mental Health Center, Nanjing Medical University, Wuxi, 214151, Jiangsu, China.
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Abstract
Autism is a common and complex neurologic disorder whose scientific underpinnings have begun to be established in the past decade. The essence of this breakthrough has been a focus on families, where genetic analyses are strongest, versus large-scale, case-control studies. Autism genetics has progressed in parallel with technology, from analyses of copy number variation to whole-exome sequencing (WES) and whole-genome sequencing (WGS). Gene mutations causing complete loss of function account for perhaps one-third of cases, largely detected through WES. This limitation has increased interest in understanding the regulatory variants of genes that contribute in more subtle ways to the disorder. Strategies combining biochemical analysis of gene regulation, WGS analysis of the noncoding genome, and machine learning have begun to succeed. The emerging picture is that careful control of the amounts of transcription, mRNA, and proteins made by key brain genes-stoichiometry-plays a critical role in defining the clinical features of autism.
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Affiliation(s)
- Robert B Darnell
- Laboratory of Molecular Neuro-Oncology, Howard Hughes Medical Institute, The Rockefeller University, New York, NY 10065, USA;
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Pan Y, He X, Li C, Li Y, Li W, Zhang H, Wang Y, Zhou G, Yang J, Li J, Qu J, Wang H, Gao Z, Shen Y, Li T, Hu H, Ma H. Neuronal activity recruits the CRTC1/CREB axis to drive transcription-dependent autophagy for maintaining late-phase LTD. Cell Rep 2021; 36:109398. [PMID: 34289350 DOI: 10.1016/j.celrep.2021.109398] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2020] [Revised: 05/05/2021] [Accepted: 06/22/2021] [Indexed: 12/31/2022] Open
Abstract
Cellular resources must be reorganized for long-term synaptic plasticity during brain information processing, in which coordinated gene transcription and protein turnover are required. However, the mechanism underlying this process remains elusive. Here, we report that activating N-methyl-d-aspartate receptors (NMDARs) induce transcription-dependent autophagy for synaptic turnover and late-phase long-term synaptic depression (L-LTD), which invokes cytoplasm-to-nucleus signaling mechanisms known to be required for late-phase long-term synaptic potentiation (L-LTP). Mechanistically, LTD-inducing stimuli specifically dephosphorylate CRTC1 (CREB-regulated transcription coactivator 1) at Ser-151 and are advantaged in recruiting CRTC1 from cytoplasm to the nucleus, where it competes with FXR (fed-state sensing nuclear receptor) for binding to CREB (cAMP response element-binding protein) and drives autophagy gene expression. Disrupting synergistic actions of CREB and CRTC1 (two essential L-LTP transcription factors) impairs transcription-dependent autophagy induction and prevents NMDAR-dependent L-LTD, which can be rescued by constitutively inducing mechanistic target of rapamycin (mTOR)-dependent autophagy. Together, these findings uncover mechanistic commonalities between L-LTP and L-LTD, suggesting that synaptic activity can tune excitation-transcription coupling for distinct long-lasting synaptic remodeling.
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Affiliation(s)
- Yue Pan
- Department of Neurobiology and Department of Neurology of Second Affiliated Hospital, Affiliated Mental Health Center, Zhejiang University School of Medicine, Hangzhou 310058, China; NHC and CAMS Key Laboratory of Medical Neurobiology, MOE Frontier Science Center for Brain Research and Brain-Machine Integration, School of Brain Science and Brain Medicine, Zhejiang University, Hangzhou 310058, China
| | - Xingzhi He
- Department of Neurobiology and Department of Neurology of Second Affiliated Hospital, Affiliated Mental Health Center, Zhejiang University School of Medicine, Hangzhou 310058, China; NHC and CAMS Key Laboratory of Medical Neurobiology, MOE Frontier Science Center for Brain Research and Brain-Machine Integration, School of Brain Science and Brain Medicine, Zhejiang University, Hangzhou 310058, China
| | - Cuicui Li
- Department of Neurobiology and Department of Neurology of Second Affiliated Hospital, Affiliated Mental Health Center, Zhejiang University School of Medicine, Hangzhou 310058, China; NHC and CAMS Key Laboratory of Medical Neurobiology, MOE Frontier Science Center for Brain Research and Brain-Machine Integration, School of Brain Science and Brain Medicine, Zhejiang University, Hangzhou 310058, China
| | - Yanjun Li
- Department of Neurobiology and Department of Neurology of Second Affiliated Hospital, Affiliated Mental Health Center, Zhejiang University School of Medicine, Hangzhou 310058, China; NHC and CAMS Key Laboratory of Medical Neurobiology, MOE Frontier Science Center for Brain Research and Brain-Machine Integration, School of Brain Science and Brain Medicine, Zhejiang University, Hangzhou 310058, China
| | - Wenwen Li
- Department of Neurobiology and Department of Neurology of Second Affiliated Hospital, Affiliated Mental Health Center, Zhejiang University School of Medicine, Hangzhou 310058, China; NHC and CAMS Key Laboratory of Medical Neurobiology, MOE Frontier Science Center for Brain Research and Brain-Machine Integration, School of Brain Science and Brain Medicine, Zhejiang University, Hangzhou 310058, China
| | - Hanbin Zhang
- Department of Neurobiology and Department of Neurology of Second Affiliated Hospital, Affiliated Mental Health Center, Zhejiang University School of Medicine, Hangzhou 310058, China; NHC and CAMS Key Laboratory of Medical Neurobiology, MOE Frontier Science Center for Brain Research and Brain-Machine Integration, School of Brain Science and Brain Medicine, Zhejiang University, Hangzhou 310058, China
| | - Yang Wang
- Department of Neurobiology and Department of Neurology of Second Affiliated Hospital, Affiliated Mental Health Center, Zhejiang University School of Medicine, Hangzhou 310058, China; NHC and CAMS Key Laboratory of Medical Neurobiology, MOE Frontier Science Center for Brain Research and Brain-Machine Integration, School of Brain Science and Brain Medicine, Zhejiang University, Hangzhou 310058, China
| | - Guangjun Zhou
- Department of Neurobiology and Department of Neurology of Second Affiliated Hospital, Affiliated Mental Health Center, Zhejiang University School of Medicine, Hangzhou 310058, China; NHC and CAMS Key Laboratory of Medical Neurobiology, MOE Frontier Science Center for Brain Research and Brain-Machine Integration, School of Brain Science and Brain Medicine, Zhejiang University, Hangzhou 310058, China
| | - Jing Yang
- Department of Neurobiology and Department of Neurology of Second Affiliated Hospital, Affiliated Mental Health Center, Zhejiang University School of Medicine, Hangzhou 310058, China; NHC and CAMS Key Laboratory of Medical Neurobiology, MOE Frontier Science Center for Brain Research and Brain-Machine Integration, School of Brain Science and Brain Medicine, Zhejiang University, Hangzhou 310058, China
| | - Jiarui Li
- Department of Neurobiology and Department of Neurology of Second Affiliated Hospital, Affiliated Mental Health Center, Zhejiang University School of Medicine, Hangzhou 310058, China; NHC and CAMS Key Laboratory of Medical Neurobiology, MOE Frontier Science Center for Brain Research and Brain-Machine Integration, School of Brain Science and Brain Medicine, Zhejiang University, Hangzhou 310058, China
| | - Jing Qu
- Department of Neurobiology and Department of Neurology of Second Affiliated Hospital, Affiliated Mental Health Center, Zhejiang University School of Medicine, Hangzhou 310058, China; NHC and CAMS Key Laboratory of Medical Neurobiology, MOE Frontier Science Center for Brain Research and Brain-Machine Integration, School of Brain Science and Brain Medicine, Zhejiang University, Hangzhou 310058, China
| | - Hao Wang
- Department of Neurobiology and Department of Neurology of Second Affiliated Hospital, Affiliated Mental Health Center, Zhejiang University School of Medicine, Hangzhou 310058, China; NHC and CAMS Key Laboratory of Medical Neurobiology, MOE Frontier Science Center for Brain Research and Brain-Machine Integration, School of Brain Science and Brain Medicine, Zhejiang University, Hangzhou 310058, China
| | - Zhihua Gao
- Department of Neurobiology and Department of Neurology of Second Affiliated Hospital, Affiliated Mental Health Center, Zhejiang University School of Medicine, Hangzhou 310058, China; NHC and CAMS Key Laboratory of Medical Neurobiology, MOE Frontier Science Center for Brain Research and Brain-Machine Integration, School of Brain Science and Brain Medicine, Zhejiang University, Hangzhou 310058, China
| | - Ying Shen
- Department of Neurobiology and Department of Neurology of Second Affiliated Hospital, Affiliated Mental Health Center, Zhejiang University School of Medicine, Hangzhou 310058, China; NHC and CAMS Key Laboratory of Medical Neurobiology, MOE Frontier Science Center for Brain Research and Brain-Machine Integration, School of Brain Science and Brain Medicine, Zhejiang University, Hangzhou 310058, China
| | - Tao Li
- Department of Neurobiology and Department of Neurology of Second Affiliated Hospital, Affiliated Mental Health Center, Zhejiang University School of Medicine, Hangzhou 310058, China; NHC and CAMS Key Laboratory of Medical Neurobiology, MOE Frontier Science Center for Brain Research and Brain-Machine Integration, School of Brain Science and Brain Medicine, Zhejiang University, Hangzhou 310058, China
| | - Hailan Hu
- Department of Neurobiology and Department of Neurology of Second Affiliated Hospital, Affiliated Mental Health Center, Zhejiang University School of Medicine, Hangzhou 310058, China; NHC and CAMS Key Laboratory of Medical Neurobiology, MOE Frontier Science Center for Brain Research and Brain-Machine Integration, School of Brain Science and Brain Medicine, Zhejiang University, Hangzhou 310058, China; Research Units for Emotion and Emotion Disorders, Chinese Academy of Medical Sciences, Beijing 100730, China
| | - Huan Ma
- Department of Neurobiology and Department of Neurology of Second Affiliated Hospital, Affiliated Mental Health Center, Zhejiang University School of Medicine, Hangzhou 310058, China; NHC and CAMS Key Laboratory of Medical Neurobiology, MOE Frontier Science Center for Brain Research and Brain-Machine Integration, School of Brain Science and Brain Medicine, Zhejiang University, Hangzhou 310058, China; Research Units for Emotion and Emotion Disorders, Chinese Academy of Medical Sciences, Beijing 100730, China.
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Rajgor D, Welle TM, Smith KR. The Coordination of Local Translation, Membranous Organelle Trafficking, and Synaptic Plasticity in Neurons. Front Cell Dev Biol 2021; 9:711446. [PMID: 34336865 PMCID: PMC8317219 DOI: 10.3389/fcell.2021.711446] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2021] [Accepted: 06/14/2021] [Indexed: 12/16/2022] Open
Abstract
Neurons are highly complex polarized cells, displaying an extraordinary degree of spatial compartmentalization. At presynaptic and postsynaptic sites, far from the cell body, local protein synthesis is utilized to continually modify the synaptic proteome, enabling rapid changes in protein production to support synaptic function. Synapses undergo diverse forms of plasticity, resulting in long-term, persistent changes in synapse strength, which are paramount for learning, memory, and cognition. It is now well-established that local translation of numerous synaptic proteins is essential for many forms of synaptic plasticity, and much work has gone into deciphering the strategies that neurons use to regulate activity-dependent protein synthesis. Recent studies have pointed to a coordination of the local mRNA translation required for synaptic plasticity and the trafficking of membranous organelles in neurons. This includes the co-trafficking of RNAs to their site of action using endosome/lysosome “transports,” the regulation of activity-dependent translation at synapses, and the role of mitochondria in fueling synaptic translation. Here, we review our current understanding of these mechanisms that impact local translation during synaptic plasticity, providing an overview of these novel and nuanced regulatory processes involving membranous organelles in neurons.
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Affiliation(s)
- Dipen Rajgor
- Department of Pharmacology, University of Colorado School of Medicine, Aurora, CO, United States
| | - Theresa M Welle
- Department of Pharmacology, University of Colorado School of Medicine, Aurora, CO, United States
| | - Katharine R Smith
- Department of Pharmacology, University of Colorado School of Medicine, Aurora, CO, United States
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Di Cicco G, Marzano E, Iacovelli L, Celli R, van Luijtelaar G, Nicoletti F, Ngomba RT, Wall MJ. Group I metabotropic glutamate receptor-mediated long term depression is disrupted in the hippocampus of WAG/Rij rats modelling absence epilepsy. Neuropharmacology 2021; 196:108686. [PMID: 34197893 DOI: 10.1016/j.neuropharm.2021.108686] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2021] [Revised: 06/16/2021] [Accepted: 06/17/2021] [Indexed: 11/19/2022]
Abstract
Absence epilepsy is frequently associated with cognitive dysfunction, although the underlying mechanisms are not well understood. Here we report that some forms of hippocampal synaptic plasticity are abnormal in symptomatic Wistar Albino Glaxo/Rijswijk (WAG/Rij) rats. Metabotropic Glu 1/5 receptor-mediated long term depression (LTD) at Schaffer collateral CA1 synapses is significantly reduced in symptomatic, 5-6 months old WAG/Rij rats compared to age-matched non epileptic control rats. There were no significant changes in mGlu1/5-dependent LTD in pre-symptomatic, 4-6 weeks old WAG/Rij rats compared to age matched controls. The changes in LTD found in symptomatic WAG/Rij forms are not indicative of general deficits in all forms of synaptic plasticity as long term potentiation (LTP) was unchanged. Immunoblot analysis of hippocampal tissue showed a significant reduction in mGlu5 receptor expression, a trend to an increase in pan Homer protein levels and a decrease in GluA1 receptor expression in the hippocampus of symptomatic WAG/Rij rats vs non-epileptic control rats. There were no changes in mGlu1α receptor or GluA2 protein levels. These findings suggest that abnormalities in hippocampal mGlu5 receptor-dependent synaptic plasticity are associated with the pathological phenotype of WAG/Rij rats. This lays the groundwork for the study of mGlu5 receptors as a candidate drug target for the treatment of cognitive dysfunction linked to absence epilepsy.
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Affiliation(s)
- Gabriele Di Cicco
- Departments of Physiology and Pharmacology, University Sapienza of Rome, Italy
| | - Emanuela Marzano
- Departments of Physiology and Pharmacology, University Sapienza of Rome, Italy
| | - Luisa Iacovelli
- Departments of Physiology and Pharmacology, University Sapienza of Rome, Italy
| | | | | | - Ferdinando Nicoletti
- Departments of Physiology and Pharmacology, University Sapienza of Rome, Italy; IRCCS Neuromed, Pozzilli, Italy
| | - Richard T Ngomba
- University of Lincoln, School of Pharmacy Lincoln, United Kingdom; and, Coventry, UK.
| | - Mark J Wall
- School of Life Sciences, University of Warwick, Coventry, UK.
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Mills A, Gago F. On the Need to Tell Apart Fraternal Twins eEF1A1 and eEF1A2, and Their Respective Outfits. Int J Mol Sci 2021; 22:6973. [PMID: 34203525 PMCID: PMC8268798 DOI: 10.3390/ijms22136973] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2021] [Revised: 06/25/2021] [Accepted: 06/25/2021] [Indexed: 01/03/2023] Open
Abstract
eEF1A1 and eEF1A2 are paralogous proteins whose presence in most normal eukaryotic cells is mutually exclusive and developmentally regulated. Often described in the scientific literature under the collective name eEF1A, which stands for eukaryotic elongation factor 1A, their best known activity (in a monomeric, GTP-bound conformation) is to bind aminoacyl-tRNAs and deliver them to the A-site of the 80S ribosome. However, both eEF1A1 and eEF1A2 are endowed with multitasking abilities (sometimes performed by homo- and heterodimers) and can be located in different subcellular compartments, from the plasma membrane to the nucleus. Given the high sequence identity of these two sister proteins and the large number of post-translational modifications they can undergo, we are often confronted with the dilemma of discerning which is the particular proteoform that is actually responsible for the ascribed biochemical or cellular effects. We argue in this review that acquiring this knowledge is essential to help clarify, in molecular and structural terms, the mechanistic involvement of these two ancestral and abundant G proteins in a variety of fundamental cellular processes other than translation elongation. Of particular importance for this special issue is the fact that several de novo heterozygous missense mutations in the human EEF1A2 gene are associated with a subset of rare but severe neurological syndromes and cardiomyopathies.
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Affiliation(s)
| | - Federico Gago
- Department of Biomedical Sciences & “Unidad Asociada IQM-CSIC”, School of Medicine and Health Sciences, University of Alcalá, E-28805 Alcalá de Henares, Spain;
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Reyes-García SE, Escobar ML. Calcineurin Participation in Hebbian and Homeostatic Plasticity Associated With Extinction. Front Cell Neurosci 2021; 15:685838. [PMID: 34220454 PMCID: PMC8242195 DOI: 10.3389/fncel.2021.685838] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2021] [Accepted: 05/25/2021] [Indexed: 12/21/2022] Open
Abstract
In nature, animals need to adapt to constant changes in their environment. Learning and memory are cognitive capabilities that allow this to happen. Extinction, the reduction of a certain behavior or learning previously established, refers to a very particular and interesting type of learning that has been the basis of a series of therapies to diminish non-adaptive behaviors. In recent years, the exploration of the cellular and molecular mechanisms underlying this type of learning has received increasing attention. Hebbian plasticity (the activity-dependent modification of the strength or efficacy of synaptic transmission), and homeostatic plasticity (the homeostatic regulation of plasticity) constitute processes intimately associated with memory formation and maintenance. Particularly, long-term depression (LTD) has been proposed as the underlying mechanism of extinction, while the protein phosphatase calcineurin (CaN) has been widely related to both the extinction process and LTD. In this review, we focus on the available evidence that sustains CaN modulation of LTD and its association with extinction. Beyond the classic view, we also examine the interconnection among extinction, Hebbian and homeostatic plasticity, as well as emergent evidence of the participation of kinases and long-term potentiation (LTP) on extinction learning, highlighting the importance of the balance between kinases and phosphatases in the expression of extinction. Finally, we also integrate data that shows the association between extinction and less-studied phenomena, such as synaptic silencing and engram formation that open new perspectives in the field.
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Affiliation(s)
- Salma E Reyes-García
- Laboratorio de Neurobiología del Aprendizaje y la Memoria, División de Investigación y Estudios de Posgrado, Facultad de Psicología, Universidad Nacional Autónoma de México, Ciudad de México, Mexico
| | - Martha L Escobar
- Laboratorio de Neurobiología del Aprendizaje y la Memoria, División de Investigación y Estudios de Posgrado, Facultad de Psicología, Universidad Nacional Autónoma de México, Ciudad de México, Mexico
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Mahaman YAR, Huang F, Embaye KS, Wang X, Zhu F. The Implication of STEP in Synaptic Plasticity and Cognitive Impairments in Alzheimer's Disease and Other Neurological Disorders. Front Cell Dev Biol 2021; 9:680118. [PMID: 34195199 PMCID: PMC8236946 DOI: 10.3389/fcell.2021.680118] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2021] [Accepted: 05/06/2021] [Indexed: 12/31/2022] Open
Abstract
STriatal-Enriched protein tyrosine Phosphatase (STEP) is a tyrosine phosphatase that has been implicated in Alzheimer’s disease (AD), the most common form of dementia, and many other neurological diseases. The protein level and activity of STEP have been found to be elevated in most of these disorders, and specifically in AD as a result of dysregulation of different pathways including PP2B/DARPP32/PP1, PKA as well as impairments of both proteasomal and lysosomal systems. The upregulation in STEP leads to increased binding to, and dephosphorylation of, its substrates which are mainly found to be synaptic plasticity and thus learning and memory related proteins. These proteins include kinases like Fyn, Pyk2, ERK1/2 and both NMDA and AMPA receptor subunits GluN2B and GluA2. The dephosphorylation of these molecules results in inactivation of these kinases and internalization of NMDA and AMPA receptor complexes leading to synapse loss and cognitive impairments. In this study, we aim to review STEP regulation and its implications in AD as well as other neurological disorders and then summarize data on targeting STEP as therapeutic strategy in these diseases.
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Affiliation(s)
- Yacoubou Abdoul Razak Mahaman
- Cognitive Impairment Ward of Neurology Department, The Third Affiliated Hospital, Shenzhen University, Shenzhen, China.,Department of Pathophysiology, School of Basic Medicine, Key Laboratory of Education Ministry of China for Neurological Disorders, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Fang Huang
- Department of Pathophysiology, School of Basic Medicine, Key Laboratory of Education Ministry of China for Neurological Disorders, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Kidane Siele Embaye
- Department of Pathophysiology, School of Basic Medicine, Key Laboratory of Education Ministry of China for Neurological Disorders, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Xiaochuan Wang
- Department of Pathophysiology, School of Basic Medicine, Key Laboratory of Education Ministry of China for Neurological Disorders, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.,Co-Innovation Center of Neuroregeneration, Nantong University, Nantong, China
| | - Feiqi Zhu
- Cognitive Impairment Ward of Neurology Department, The Third Affiliated Hospital, Shenzhen University, Shenzhen, China
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