1
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López-Hidalgo R, Ballestín R, Lorenzo L, Sánchez-Martí S, Blasco-Ibáñez JM, Crespo C, Nacher J, Varea E. Early chronic fasudil treatment rescues hippocampal alterations in the Ts65Dn model for down syndrome. Neurochem Int 2024; 174:105679. [PMID: 38309665 DOI: 10.1016/j.neuint.2024.105679] [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: 10/06/2023] [Revised: 01/23/2024] [Accepted: 01/24/2024] [Indexed: 02/05/2024]
Abstract
Down syndrome (DS) is the most common genetic disorder associated with intellectual disability. To study this syndrome, several mouse models have been developed. Among the most common is the Ts65Dn model, which mimics most of the alterations observed in DS. Ts65Dn mice, as humans with DS, show defects in the structure, density, and distribution of dendritic spines in the cerebral cortex and hippocampus. Fasudil is a potent inhibitor of the RhoA kinase pathway, which is involved in the formation and stabilization of dendritic spines. Our study analysed the effect of early chronic fasudil treatment on the alterations observed in the hippocampus of the Ts65Dn model. We observed that treating Ts65Dn mice with fasudil induced an increase in neural plasticity in the hippocampus: there was an increment in the expression of PSA-NCAM and BDNF, in the dendritic branching and spine density of granule neurons, as well as in cell proliferation and neurogenesis in the subgranular zone. Finally, the treatment reduced the unbalance between excitation and inhibition present in this model. Overall, early chronic treatment with fasudil increases cell plasticity and eliminates differences with euploid animals.
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Affiliation(s)
- Rosa López-Hidalgo
- Neurobiology Unit, Institute for Biotechnology and Biomedicine (BIOTECMED), University of Valencia, Spain
| | - Raúl Ballestín
- Neurobiology Unit, Institute for Biotechnology and Biomedicine (BIOTECMED), University of Valencia, Spain
| | - Lorena Lorenzo
- Neurobiology Unit, Institute for Biotechnology and Biomedicine (BIOTECMED), University of Valencia, Spain
| | - Sandra Sánchez-Martí
- Neurobiology Unit, Institute for Biotechnology and Biomedicine (BIOTECMED), University of Valencia, Spain
| | - José Miguel Blasco-Ibáñez
- Neurobiology Unit, Institute for Biotechnology and Biomedicine (BIOTECMED), University of Valencia, Spain
| | - Carlos Crespo
- Neurobiology Unit, Institute for Biotechnology and Biomedicine (BIOTECMED), University of Valencia, Spain
| | - Juan Nacher
- Neurobiology Unit, Institute for Biotechnology and Biomedicine (BIOTECMED), University of Valencia, Spain; CIBERSAM, Spanish National Network for Research in Mental Health, Madrid, Spain; Institute of research of the Clinic Hospital from Valencia (INCLIVA), Valencia, Spain
| | - Emilio Varea
- Neurobiology Unit, Institute for Biotechnology and Biomedicine (BIOTECMED), University of Valencia, Spain.
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2
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Kuil LE, Chauhan RK, de Graaf BM, Cheng WW, Kakiailatu NJM, Lasabuda R, Verhaeghe C, Windster JD, Schriemer D, Azmani Z, Brooks AS, Edie S, Reeves RH, Eggen BJL, Shepherd IT, Burns AJ, Hofstra RMW, Melotte V, Brosens E, Alves MM. ATP5PO levels regulate enteric nervous system development in zebrafish, linking Hirschsprung disease to Down Syndrome. Biochim Biophys Acta Mol Basis Dis 2024; 1870:166991. [PMID: 38128843 DOI: 10.1016/j.bbadis.2023.166991] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2023] [Revised: 12/09/2023] [Accepted: 12/11/2023] [Indexed: 12/23/2023]
Abstract
Hirschsprung disease (HSCR) is a complex genetic disorder characterized by the absence of enteric nervous system (ENS) in the distal region of the intestine. Down Syndrome (DS) patients have a >50-fold higher risk of developing HSCR than the general population, suggesting that overexpression of human chromosome 21 (Hsa21) genes contribute to HSCR etiology. However, identification of responsible genes remains challenging. Here, we describe a genetic screening of potential candidate genes located on Hsa21, using the zebrafish. Candidate genes were located in the DS-HSCR susceptibility region, expressed in the human intestine, were known potential biomarkers for DS prenatal diagnosis, and were present in the zebrafish genome. With this approach, four genes were selected: RCAN1, ITSN1, ATP5PO and SUMO3. However, only overexpression of ATP5PO, coding for a component of the mitochondrial ATPase, led to significant reduction of ENS cells. Paradoxically, in vitro studies showed that overexpression of ATP5PO led to a reduction of ATP5PO protein levels. Impaired neuronal differentiation and reduced mitochondrial ATP production, were also detected in vitro, after overexpression of ATP5PO in a neuroblastoma cell line. Finally, epistasis was observed between ATP5PO and ret, the most important HSCR gene. Taken together, our results identify ATP5PO as the gene responsible for the increased risk of HSCR in DS patients in particular if RET variants are also present, and show that a balanced expression of ATP5PO is required for normal ENS development.
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Affiliation(s)
- L E Kuil
- Department of Clinical Genetics, Erasmus University Medical Center Rotterdam - Sophia Children's Hospital, Rotterdam, the Netherlands
| | - R K Chauhan
- Department of Clinical Genetics, Erasmus University Medical Center Rotterdam - Sophia Children's Hospital, Rotterdam, the Netherlands
| | - B M de Graaf
- Department of Clinical Genetics, Erasmus University Medical Center Rotterdam - Sophia Children's Hospital, Rotterdam, the Netherlands
| | - W W Cheng
- Department of Clinical Genetics, Erasmus University Medical Center Rotterdam - Sophia Children's Hospital, Rotterdam, the Netherlands
| | - N J M Kakiailatu
- Department of Clinical Genetics, Erasmus University Medical Center Rotterdam - Sophia Children's Hospital, Rotterdam, the Netherlands
| | - R Lasabuda
- Department of Clinical Genetics, Erasmus University Medical Center Rotterdam - Sophia Children's Hospital, Rotterdam, the Netherlands
| | - C Verhaeghe
- Department of Clinical Genetics, Erasmus University Medical Center Rotterdam - Sophia Children's Hospital, Rotterdam, the Netherlands
| | - J D Windster
- Department of Clinical Genetics, Erasmus University Medical Center Rotterdam - Sophia Children's Hospital, Rotterdam, the Netherlands; Department of Pediatric Surgery, Erasmus University Medical Center Rotterdam, Sophia's Children's Hospital, Rotterdam, the Netherlands
| | - D Schriemer
- Department of Biomedical Sciences of Cells and Systems, Section Molecular Neurobiology, University of Groningen, University Medical Center Groningen, Groningen, the Netherlands
| | - Z Azmani
- Department of Clinical Genetics, Erasmus University Medical Center Rotterdam - Sophia Children's Hospital, Rotterdam, the Netherlands
| | - A S Brooks
- Department of Clinical Genetics, Erasmus University Medical Center Rotterdam - Sophia Children's Hospital, Rotterdam, the Netherlands
| | - S Edie
- Johns Hopkins University School of Medicine, Department of Physiology and McKusick-Nathans Department of Genetic Medicine, Baltimore, MD, United States of America
| | - R H Reeves
- Johns Hopkins University School of Medicine, Department of Physiology and McKusick-Nathans Department of Genetic Medicine, Baltimore, MD, United States of America
| | - B J L Eggen
- Department of Biomedical Sciences of Cells and Systems, Section Molecular Neurobiology, University of Groningen, University Medical Center Groningen, Groningen, the Netherlands
| | - I T Shepherd
- Department of Biology, Emory University, Atlanta, GA, United States of America
| | - A J Burns
- Department of Clinical Genetics, Erasmus University Medical Center Rotterdam - Sophia Children's Hospital, Rotterdam, the Netherlands; Birth Defects Research Centre, UCL Institute of Child Health, London, United Kingdom; Gastrointestinal Drug Discovery Unit, Takeda Pharmaceuticals, Cambridge, MA, United States of America
| | - R M W Hofstra
- Department of Clinical Genetics, Erasmus University Medical Center Rotterdam - Sophia Children's Hospital, Rotterdam, the Netherlands
| | - V Melotte
- Department of Clinical Genetics, Erasmus University Medical Center Rotterdam - Sophia Children's Hospital, Rotterdam, the Netherlands; Department of Pathology, GROW-school for Oncology and Developmental Biology, Maastricht University Medical Center, Maastricht, the Netherlands
| | - E Brosens
- Department of Clinical Genetics, Erasmus University Medical Center Rotterdam - Sophia Children's Hospital, Rotterdam, the Netherlands
| | - M M Alves
- Department of Clinical Genetics, Erasmus University Medical Center Rotterdam - Sophia Children's Hospital, Rotterdam, the Netherlands; Department of Pediatric Surgery, Erasmus University Medical Center Rotterdam, Sophia's Children's Hospital, Rotterdam, the Netherlands.
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3
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Schneider F, Metz I, Rust MB. Regulation of actin filament assembly and disassembly in growth cone motility and axon guidance. Brain Res Bull 2023; 192:21-35. [PMID: 36336143 DOI: 10.1016/j.brainresbull.2022.10.019] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2022] [Revised: 10/26/2022] [Accepted: 10/28/2022] [Indexed: 11/06/2022]
Abstract
Directed outgrowth of axons is fundamental for the establishment of neuronal networks. Axon outgrowth is guided by growth cones, highly motile structures enriched in filamentous actin (F-actin) located at the axons' distal tips. Growth cones exploit F-actin-based protrusions to scan the environment for guidance cues, and they contain the sensory apparatus to translate guidance cue information into intracellular signaling cascades. These cascades act upstream of actin-binding proteins (ABP) and thereby control assembly and disassembly of F-actin. Spatiotemporally controlled F-actin dis-/assembly in growth cones steers the axon towards attractants and away from repellents, and it thereby navigates the axon through the developing nervous system. Hence, ABP that control F-actin dynamics emerged as critical regulators of neuronal network formation. In the present review article, we will summarize and discuss current knowledge of the mechanisms that control remodeling of the actin cytoskeleton in growth cones, focusing on recent progress in the field. Further, we will introduce tools and techniques that allow to study actin regulatory mechanism in growth cones.
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Affiliation(s)
- Felix Schneider
- Molecular Neurobiology Group, Institute of Physiological Chemistry, Philipps-University of Marburg, 35032 Marburg, Germany; DFG Research Training Group 'Membrane Plasticity in Tissue Development and Remodeling', GRK 2213, Philipps-University of Marburg, 35032 Marburg, Germany; Molecular Urooncology, Department of Urology, University Hospital Heidelberg, 69120 Heidelberg, Germany
| | - Isabell Metz
- Molecular Neurobiology Group, Institute of Physiological Chemistry, Philipps-University of Marburg, 35032 Marburg, Germany; DFG Research Training Group 'Membrane Plasticity in Tissue Development and Remodeling', GRK 2213, Philipps-University of Marburg, 35032 Marburg, Germany
| | - Marco B Rust
- Molecular Neurobiology Group, Institute of Physiological Chemistry, Philipps-University of Marburg, 35032 Marburg, Germany; DFG Research Training Group 'Membrane Plasticity in Tissue Development and Remodeling', GRK 2213, Philipps-University of Marburg, 35032 Marburg, Germany; Center for Mind, Brain and Behavior (CMBB), University of Marburg and Justus-Liebig-University Giessen, 35032 Marburg, Germany.
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4
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mtIF3 is locally translated in axons and regulates mitochondrial translation for axonal growth. BMC Biol 2022; 20:12. [PMID: 34996455 PMCID: PMC8742369 DOI: 10.1186/s12915-021-01215-w] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2021] [Accepted: 11/09/2021] [Indexed: 11/13/2022] Open
Abstract
Background The establishment and maintenance of functional neural connections relies on appropriate distribution and localization of mitochondria in neurites, as these organelles provide essential energy and metabolites. In particular, mitochondria are transported to axons and support local energy production to maintain energy-demanding neuronal processes including axon branching, growth, and regeneration. Additionally, local protein synthesis is required for structural and functional changes in axons, with nuclear-encoded mitochondrial mRNAs having been found localized in axons. However, it remains unclear whether these mRNAs are locally translated and whether the potential translated mitochondrial proteins are involved in the regulation of mitochondrial functions in axons. Here, we aim to further understand the purpose of such compartmentalization by focusing on the role of mitochondrial initiation factor 3 (mtIF3), whose nuclear-encoded transcripts have been shown to be present in axonal growth cones. Results We demonstrate that brain-derived neurotrophic factor (BDNF) induces local translation of mtIF3 mRNA in axonal growth cones. Subsequently, mtIF3 protein is translocated into axonal mitochondria and promotes mitochondrial translation as assessed by our newly developed bimolecular fluorescence complementation sensor for the assembly of mitochondrial ribosomes. We further show that BDNF-induced axonal growth requires mtIF3-dependent mitochondrial translation in distal axons. Conclusion We describe a previously unknown function of mitochondrial initiation factor 3 (mtIF3) in axonal protein synthesis and development. These findings provide insight into the way neurons adaptively control mitochondrial physiology and axonal development via local mtIF3 translation. Supplementary Information The online version contains supplementary material available at 10.1186/s12915-021-01215-w.
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5
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Agrawal M, Welshhans K. Local Translation Across Neural Development: A Focus on Radial Glial Cells, Axons, and Synaptogenesis. Front Mol Neurosci 2021; 14:717170. [PMID: 34434089 PMCID: PMC8380849 DOI: 10.3389/fnmol.2021.717170] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2021] [Accepted: 07/20/2021] [Indexed: 11/13/2022] Open
Abstract
In the past two decades, significant progress has been made in our understanding of mRNA localization and translation at distal sites in axons and dendrites. The existing literature shows that local translation is regulated in a temporally and spatially restricted manner and is critical throughout embryonic and post-embryonic life. Here, recent key findings about mRNA localization and local translation across the various stages of neural development, including neurogenesis, axon development, and synaptogenesis, are reviewed. In the early stages of development, mRNAs are localized and locally translated in the endfeet of radial glial cells, but much is still unexplored about their functional significance. Recent in vitro and in vivo studies have provided new information about the specific mechanisms regulating local translation during axon development, including growth cone guidance and axon branching. Later in development, localization and translation of mRNAs help mediate the major structural and functional changes that occur in the axon during synaptogenesis. Clinically, changes in local translation across all stages of neural development have important implications for understanding the etiology of several neurological disorders. Herein, local translation and mechanisms regulating this process across developmental stages are compared and discussed in the context of function and dysfunction.
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Affiliation(s)
- Manasi Agrawal
- School of Biomedical Sciences, Kent State University, Kent, OH, United States
| | - Kristy Welshhans
- Department of Biological Sciences, University of South Carolina, Columbia, SC, United States
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6
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Schneider F, Duong TA, Metz I, Winkelmeier J, Hübner CA, Endesfelder U, Rust MB. Mutual functional dependence of cyclase-associated protein 1 (CAP1) and cofilin1 in neuronal actin dynamics and growth cone function. Prog Neurobiol 2021; 202:102050. [PMID: 33845164 DOI: 10.1016/j.pneurobio.2021.102050] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2020] [Revised: 02/14/2021] [Accepted: 04/07/2021] [Indexed: 01/20/2023]
Abstract
Neuron connectivity depends on growth cones that navigate axons through the developing brain. Growth cones protrude and retract actin-rich structures to sense guidance cues. These cues control local actin dynamics and steer growth cones towards attractants and away from repellents, thereby directing axon outgrowth. Hence, actin binding proteins (ABPs) moved into the focus as critical regulators of neuron connectivity. We found cyclase-associated protein 1 (CAP1), an ABP with unknown brain function, abundant in growth cones. Super-resolution microscopy and live cell imaging combined with pharmacological approaches on hippocampal neurons from gene-targeted mice revealed a crucial role for CAP1 in actin dynamics that is critical for growth cone morphology and function. Growth cone defects in CAP1 knockout (KO) neurons compromised neuron differentiation and was associated with impaired neuron connectivity in CAP1-KO brains. Mechanistically, by rescue experiments in double KO neurons lacking CAP1 and the key actin regulator cofilin1, we demonstrated that CAP1 was essential for cofilin1 function in growth cone actin dynamics and morphology and vice versa. Together, we identified CAP1 as a novel actin regulator in growth cones that was relevant for neuron connectivity, and we demonstrated functional interdependence of CAP1 and cofilin1 in neuronal actin dynamics and growth cone function.
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Affiliation(s)
- Felix Schneider
- Molecular Neurobiology Group, Institute of Physiological Chemistry, University of Marburg, 35032, Marburg, Germany; Center for Mind, Brain and Behavior (CMBB), University of Marburg and Justus-Liebig-University Giessen, 35032, Marburg, Germany; DFG Research Training Group, Membrane Plasticity in Tissue Development and Remodeling, GRK 2213, Philipps-University of Marburg, 35032, Marburg, Germany
| | - Thuy-An Duong
- Molecular Neurobiology Group, Institute of Physiological Chemistry, University of Marburg, 35032, Marburg, Germany
| | - Isabell Metz
- Molecular Neurobiology Group, Institute of Physiological Chemistry, University of Marburg, 35032, Marburg, Germany; Center for Mind, Brain and Behavior (CMBB), University of Marburg and Justus-Liebig-University Giessen, 35032, Marburg, Germany
| | - Jannik Winkelmeier
- Department of Systems and Synthetic Microbiology, Max Planck Institute for Terrestrial Microbiology and LOEWE Center for Synthetic Microbiology (SYNMIKRO), 35043, Marburg, Germany; Department of Physics, Mellon College of Science, Carnegie-Mellon University, Pittsburgh, PA, USA
| | - Christian A Hübner
- Institute of Human Genetics, University Hospital Jena, 07743, Jena, Germany
| | - Ulrike Endesfelder
- Department of Systems and Synthetic Microbiology, Max Planck Institute for Terrestrial Microbiology and LOEWE Center for Synthetic Microbiology (SYNMIKRO), 35043, Marburg, Germany; Department of Physics, Mellon College of Science, Carnegie-Mellon University, Pittsburgh, PA, USA
| | - Marco B Rust
- Molecular Neurobiology Group, Institute of Physiological Chemistry, University of Marburg, 35032, Marburg, Germany; Center for Mind, Brain and Behavior (CMBB), University of Marburg and Justus-Liebig-University Giessen, 35032, Marburg, Germany; DFG Research Training Group, Membrane Plasticity in Tissue Development and Remodeling, GRK 2213, Philipps-University of Marburg, 35032, Marburg, Germany.
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7
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Site-Specific Fluorescent Labeling of RNA Interior Positions. Molecules 2021; 26:molecules26051341. [PMID: 33802273 PMCID: PMC7959133 DOI: 10.3390/molecules26051341] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2021] [Revised: 02/26/2021] [Accepted: 03/01/2021] [Indexed: 02/08/2023] Open
Abstract
The introduction of fluorophores into RNA for both in vitro and in cellulo studies of RNA function and cellular distribution is a subject of great current interest. Here I briefly review methods, some well-established and others newly developed, which have been successfully exploited to site-specifically fluorescently label interior positions of RNAs, as a guide to investigators seeking to apply this approach to their studies. Most of these methods can be applied directly to intact RNAs, including (1) the exploitation of natural posttranslational modifications, (2) the repurposing of enzymatic transferase reactions, and (3) the nucleic acid-assisted labeling of intact RNAs. In addition, several methods are described in which specifically labeled RNAs are prepared de novo.
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8
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Martínez-Cué C, Rueda N. Signalling Pathways Implicated in Alzheimer's Disease Neurodegeneration in Individuals with and without Down Syndrome. Int J Mol Sci 2020; 21:E6906. [PMID: 32962300 PMCID: PMC7555886 DOI: 10.3390/ijms21186906] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Revised: 09/17/2020] [Accepted: 09/18/2020] [Indexed: 02/07/2023] Open
Abstract
Down syndrome (DS), the most common cause of intellectual disability of genetic origin, is characterized by alterations in central nervous system morphology and function that appear from early prenatal stages. However, by the fourth decade of life, all individuals with DS develop neuropathology identical to that found in sporadic Alzheimer's disease (AD), including the development of amyloid plaques and neurofibrillary tangles due to hyperphosphorylation of tau protein, loss of neurons and synapses, reduced neurogenesis, enhanced oxidative stress, and mitochondrial dysfunction and neuroinflammation. It has been proposed that DS could be a useful model for studying the etiopathology of AD and to search for therapeutic targets. There is increasing evidence that the neuropathological events associated with AD are interrelated and that many of them not only are implicated in the onset of this pathology but are also a consequence of other alterations. Thus, a feedback mechanism exists between them. In this review, we summarize the signalling pathways implicated in each of the main neuropathological aspects of AD in individuals with and without DS as well as the interrelation of these pathways.
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Affiliation(s)
- Carmen Martínez-Cué
- Department of Physiology and Pharmacology, Faculty of Medicine, University of Cantabria, 39011 Santander, Spain;
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9
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Koltun B, Ironi S, Gershoni-Emek N, Barrera I, Hleihil M, Nanguneri S, Sasmal R, Agasti SS, Nair D, Rosenblum K. Measuring mRNA translation in neuronal processes and somata by tRNA-FRET. Nucleic Acids Res 2020; 48:e32. [PMID: 31974573 PMCID: PMC7102941 DOI: 10.1093/nar/gkaa042] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2019] [Revised: 12/04/2019] [Accepted: 01/15/2020] [Indexed: 01/12/2023] Open
Abstract
In neurons, the specific spatial and temporal localization of protein synthesis is of great importance for function and survival. Here, we visualized tRNA and protein synthesis events in fixed and live mouse primary cortical culture using fluorescently-labeled tRNAs. We were able to characterize the distribution and transport of tRNAs in different neuronal sub-compartments and to study their association with the ribosome. We found that tRNA mobility in neural processes is lower than in somata and corresponds to patterns of slow transport mechanisms, and that larger tRNA puncta co-localize with translational machinery components and are likely the functional fraction. Furthermore, chemical induction of long-term potentiation (LTP) in culture revealed up-regulation of mRNA translation with a similar effect in dendrites and somata, which appeared to be GluR-dependent 6 h post-activation. Importantly, measurement of protein synthesis in neurons with high resolutions offers new insights into neuronal function in health and disease states.
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Affiliation(s)
- Bella Koltun
- Sagol Department of Neurobiology, University of Haifa, Haifa, Israel
| | - Sivan Ironi
- Sagol Department of Neurobiology, University of Haifa, Haifa, Israel
| | | | - Iliana Barrera
- Sagol Department of Neurobiology, University of Haifa, Haifa, Israel
| | - Mohammad Hleihil
- Sagol Department of Neurobiology, University of Haifa, Haifa, Israel
| | | | - Ranjan Sasmal
- New Chemistry Unit and Chemistry & Physics of Materials Unit, Jawaharlal Nehru Centre for Advanced Scientific Research (JNCASR), Bangalore, Karnataka, India
| | - Sarit S Agasti
- New Chemistry Unit and Chemistry & Physics of Materials Unit, Jawaharlal Nehru Centre for Advanced Scientific Research (JNCASR), Bangalore, Karnataka, India
| | - Deepak Nair
- Centre for Neuroscience, Indian Institute of Science, Bangalore, India
| | - Kobi Rosenblum
- Sagol Department of Neurobiology, University of Haifa, Haifa, Israel.,Center for Gene Manipulation in the Brain, University of Haifa, Haifa, Israel
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10
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Expression of Genes Involved in Axon Guidance: How Much Have We Learned? Int J Mol Sci 2020; 21:ijms21103566. [PMID: 32443632 PMCID: PMC7278939 DOI: 10.3390/ijms21103566] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2020] [Revised: 05/15/2020] [Accepted: 05/16/2020] [Indexed: 12/20/2022] Open
Abstract
Neuronal axons are guided to their target during the development of the brain. Axon guidance allows the formation of intricate neural circuits that control the function of the brain, and thus the behavior. As the axons travel in the brain to find their target, they encounter various axon guidance cues, which interact with the receptors on the tip of the growth cone to permit growth along different signaling pathways. Although many scientists have performed numerous studies on axon guidance signaling pathways, we still have an incomplete understanding of the axon guidance system. Lately, studies on axon guidance have shifted from studying the signal transduction pathways to studying other molecular features of axon guidance, such as the gene expression. These new studies present evidence for different molecular features that broaden our understanding of axon guidance. Hence, in this review we will introduce recent studies that illustrate different molecular features of axon guidance. In particular, we will review literature that demonstrates how axon guidance cues and receptors regulate local translation of axonal genes and how the expression of guidance cues and receptors are regulated both transcriptionally and post-transcriptionally. Moreover, we will highlight the pathological relevance of axon guidance molecules to specific diseases.
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11
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Batool S, Raza H, Zaidi J, Riaz S, Hasan S, Syed NI. Synapse formation: from cellular and molecular mechanisms to neurodevelopmental and neurodegenerative disorders. J Neurophysiol 2019; 121:1381-1397. [PMID: 30759043 DOI: 10.1152/jn.00833.2018] [Citation(s) in RCA: 69] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
The precise patterns of neuronal assembly during development determine all functional outputs of a nervous system; these may range from simple reflexes to learning, memory, cognition, etc. To understand how brain functions and how best to repair it after injury, disease, or trauma, it is imperative that we first seek to define fundamental steps mediating this neuronal assembly. To acquire the sophisticated ensemble of highly specialized networks seen in a mature brain, all proliferated and migrated neurons must extend their axonal and dendritic processes toward targets, which are often located at some distance. Upon contact with potential partners, neurons must undergo dramatic structural changes to become either a pre- or a postsynaptic neuron. This connectivity is cemented through specialized structures termed synapses. Both structurally and functionally, the newly formed synapses are, however, not static as they undergo consistent changes in order for an animal to meet its behavioral needs in a changing environment. These changes may be either in the form of new synapses or an enhancement of their synaptic efficacy, referred to as synaptic plasticity. Thus, synapse formation is not restricted to neurodevelopment; it is a process that remains active throughout life. As the brain ages, either the lack of neuronal activity or cell death render synapses dysfunctional, thus giving rise to neurodegenerative disorders. This review seeks to highlight salient steps that are involved in a neuron's journey, starting with the establishment, maturation, and consolidation of synapses; we particularly focus on identifying key players involved in the synaptogenic program. We hope that this endeavor will not only help the beginners in this field to understand how brain networks are assembled in the first place but also shed light on various neurodevelopmental, neurological, neurodegenerative, and neuropsychiatric disorders that involve synaptic inactivity or dysfunction.
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Affiliation(s)
- Shadab Batool
- Hotchkiss Brain Institute, University of Calgary, Alberta, Canada.,Department of Neuroscience, University of Calgary, Alberta, Canada
| | - Hussain Raza
- Hotchkiss Brain Institute, University of Calgary, Alberta, Canada
| | - Jawwad Zaidi
- Hotchkiss Brain Institute, University of Calgary, Alberta, Canada
| | - Saba Riaz
- Hotchkiss Brain Institute, University of Calgary, Alberta, Canada
| | - Sean Hasan
- Hotchkiss Brain Institute, University of Calgary, Alberta, Canada
| | - Naweed I Syed
- Hotchkiss Brain Institute, University of Calgary, Alberta, Canada.,Department of Cell Biology & Anatomy, University of Calgary, Alberta, Canada
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12
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Zhang M, Ergin V, Lin L, Stork C, Chen L, Zheng S. Axonogenesis Is Coordinated by Neuron-Specific Alternative Splicing Programming and Splicing Regulator PTBP2. Neuron 2019; 101:690-706.e10. [PMID: 30733148 DOI: 10.1016/j.neuron.2019.01.022] [Citation(s) in RCA: 53] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2018] [Revised: 11/08/2018] [Accepted: 01/14/2019] [Indexed: 12/20/2022]
Abstract
How a neuron acquires an axon is a fundamental question. Piecemeal identification of many axonogenesis-related genes has been done, but coordinated regulation is unknown. Through unbiased transcriptome profiling of immature primary cortical neurons during early axon formation, we discovered an association between axonogenesis and neuron-specific alternative splicing. Known axonogenesis genes exhibit little expression alternation but widespread splicing changes. Axonogenesis-associated splicing is governed by RNA binding protein PTBP2, which is enriched in neurons and peaks around axonogenesis in the brain. Cortical depletion of PTBP2 prematurely induces axonogenesis-associated splicing, causes imbalanced expression of axonogenesis-associated isoforms, and specifically affects axon formation in vitro and in vivo. PTBP2-controlled axonogenesis-associated Shtn1 splicing determines SHTN1's capacity to regulate actin interaction, polymerization, and axon growth. Precocious Shtn1 isoform switch contributes to disorganized axon formation of Ptbp2-/- neurons. We conclude that PTBP2-orchestrated alternative splicing programming is required for robust generation of a single axon in mammals.
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Affiliation(s)
- Min Zhang
- Division of Biomedical Sciences, University of California, Riverside, Riverside, CA 92521, USA
| | - Volkan Ergin
- Division of Biomedical Sciences, University of California, Riverside, Riverside, CA 92521, USA
| | - Lin Lin
- Division of Biomedical Sciences, University of California, Riverside, Riverside, CA 92521, USA
| | - Cheryl Stork
- Graduate Program in Cell, Molecular and Developmental Biology, University of California, Riverside, Riverside, CA 92521, USA
| | - Liang Chen
- Department of Biological Sciences, Quantitative and Computational Biology, University of Southern California, Los Angeles, CA 90089, USA.
| | - Sika Zheng
- Division of Biomedical Sciences, University of California, Riverside, Riverside, CA 92521, USA; Graduate Program in Cell, Molecular and Developmental Biology, University of California, Riverside, Riverside, CA 92521, USA.
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13
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Seo JY, Jung Y, Kim DY, Ryu HG, Lee J, Kim SW, Kim KT. DAP5 increases axonal outgrowth of hippocampal neurons by enhancing the cap-independent translation of DSCR1.4 mRNA. Cell Death Dis 2019; 10:49. [PMID: 30718468 PMCID: PMC6362140 DOI: 10.1038/s41419-018-1299-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2018] [Revised: 11/30/2018] [Accepted: 12/19/2018] [Indexed: 12/18/2022]
Abstract
Proper wiring between neurons is indispensable for proper brain function. From the early developmental stage, axons grow and navigate to connect to targets according to specific guidance cues. The accuracy of axonal outgrowth and navigation are controlled by a variety of genes, and mutations and/or deficiencies in these genes are closely related to several brain disorders, such as autism. DSCR1 is one of these genes and regulates actin filament formation in axons. Thus, identifying the detailed regulatory mechanisms of DSCR1 expression is crucial for the understanding of the axon development of neurons; however, these regulatory mechanisms of DSCR1 remain unknown. Here, we discovered that mRNA encoding the DSCR1 isoform DSCR1.4 is present and mainly translated by the cap-independent initiation mechanisms in both the soma and axons of hippocampal neurons. We found that translation of DSCR1.4 mRNA is enhanced by death-associated protein 5 (DAP5), which can bind to DSCR1.4 5'UTR. BDNF-stimulus induced an increase in DAP5 expression and the cap-independent translation efficiency of DSCR1.4 mRNA in axon as well as soma. Furthermore, we showed the importance of the cap-independent translation of DSCR1.4 on enhancement of DSCR1.4 expression by BDNF-stimulus and axonal outgrowth of hippocampal neurons. Our findings suggest a new translational regulatory mechanism for DSCR1.4 expressions and a novel function of DAP5 as a positive regulator of DSCR1.4 mRNA translation induced in soma and axon of hippocampal neurons.
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Affiliation(s)
- Ji-Young Seo
- Division of Integrative Biosciences and Biotechnology, Pohang University of Science and Technology (POSTECH), Pohang, Gyeongbuk, Republic of Korea
| | - Youngseob Jung
- Division of Integrative Biosciences and Biotechnology, Pohang University of Science and Technology (POSTECH), Pohang, Gyeongbuk, Republic of Korea
| | - Do-Yeon Kim
- Department of Pharmacology, School of Dentistry, Kyungpook National University (KNU), Daegu, Republic of Korea
| | - Hye Guk Ryu
- Department of Life Sciences, Pohang University of Science and Technology (POSTECH), Pohang, Gyeongbuk, Republic of Korea
| | - Juhyun Lee
- Division of Integrative Biosciences and Biotechnology, Pohang University of Science and Technology (POSTECH), Pohang, Gyeongbuk, Republic of Korea
| | - Sung Wook Kim
- Division of Integrative Biosciences and Biotechnology, Pohang University of Science and Technology (POSTECH), Pohang, Gyeongbuk, Republic of Korea
| | - Kyong-Tai Kim
- Division of Integrative Biosciences and Biotechnology, Pohang University of Science and Technology (POSTECH), Pohang, Gyeongbuk, Republic of Korea. .,Department of Life Sciences, Pohang University of Science and Technology (POSTECH), Pohang, Gyeongbuk, Republic of Korea.
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14
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Vásquez-Navarrete J, Martínez AD, Ory S, Baéz-Matus X, González-Jamett AM, Brauchi S, Caviedes P, Cárdenas AM. RCAN1 Knockdown Reverts Defects in the Number of Calcium-Induced Exocytotic Events in a Cellular Model of Down Syndrome. Front Cell Neurosci 2018; 12:189. [PMID: 30034324 PMCID: PMC6043644 DOI: 10.3389/fncel.2018.00189] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2018] [Accepted: 06/12/2018] [Indexed: 12/15/2022] Open
Abstract
In humans, Down Syndrome (DS) is a condition caused by partial or full trisomy of chromosome 21. Genes present in the DS critical region can result in excess gene dosage, which at least partially can account for DS phenotype. Although regulator of calcineurin 1 (RCAN1) belongs to this region and its ectopic overexpression in neurons impairs transmitter release, synaptic plasticity, learning and memory, the relative contribution of RCAN1 in a context of DS has yet to be clarified. In the present work, we utilized an in vitro model of DS, the CTb neuronal cell line derived from the brain cortex of a trisomy 16 (Ts16) fetal mouse, which reportedly exhibits acetylcholine release impairments compared to CNh cells (a neuronal cell line established from a normal littermate). We analyzed single exocytotic events by using total internal reflection fluorescence microscopy (TIRFM) and the vesicular acetylcholine transporter fused to the pH-sensitive green fluorescent protein (VAChT-pHluorin) as a reporter. Our analyses showed that, compared with control CNh cells, the trisomic CTb cells overexpress RCAN1, and they display a reduced number of Ca2+-induced exocytotic events. Remarkably, RCAN1 knockdown increases the extent of exocytosis at levels comparable to those of CNh cells. These results support a critical contribution of RCAN1 to the exocytosis process in the trisomic condition.
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Affiliation(s)
- Jacqueline Vásquez-Navarrete
- Centro Interdisciplinario de Neurociencia de Valparaíso, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso, Chile
| | - Agustín D Martínez
- Centro Interdisciplinario de Neurociencia de Valparaíso, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso, Chile
| | - Stéphane Ory
- Centre National de la Recherche Scientifique (CNRS UPR 3212), Institut des Neurosciences Cellulaires et Intégratives (INCI), Strasbourg, France
| | - Ximena Baéz-Matus
- Centro Interdisciplinario de Neurociencia de Valparaíso, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso, Chile
| | - Arlek M González-Jamett
- Centro Interdisciplinario de Neurociencia de Valparaíso, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso, Chile
| | - Sebastián Brauchi
- Department of Physiology, Faculty of Medicine, Universidad Austral de Chile, Valdivia, Chile
| | - Pablo Caviedes
- Programa de Farmacología Molecular y Clínica, ICBM, Facultad de Medicina, Universidad de Chile, Santiago, Chile.,Centro de Biotecnología y Bioingeniería (CeBiB), Departamento de Ingeniería Química, Biotecnología y Materiales, Facultad de Ciencias Físicas y Matemáticas, Universidad de Chile, Santiago, Chile
| | - Ana M Cárdenas
- Centro Interdisciplinario de Neurociencia de Valparaíso, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso, Chile
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15
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Choi JH, Wang W, Park D, Kim SH, Kim KT, Min KT. IRES-mediated translation of cofilin regulates axonal growth cone extension and turning. EMBO J 2018; 37:embj.201695266. [PMID: 29440227 DOI: 10.15252/embj.201695266] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2016] [Revised: 12/19/2017] [Accepted: 01/05/2018] [Indexed: 11/09/2022] Open
Abstract
In neuronal development, dynamic rearrangement of actin promotes axonal growth cone extension, and spatiotemporal translation of local mRNAs in response to guidance cues directs axonal growth cone steering, where cofilin plays a critical role. While regulation of cofilin activity is well studied, regulatory mechanism for cofilin mRNA translation in neurons is unknown. In eukaryotic cells, proteins can be synthesized by cap-dependent or cap-independent mechanism via internal ribosome entry site (IRES)-mediated translation. IRES-mediated translation has been reported in various pathophysiological conditions, but its role in normal physiological environment is poorly understood. Here, we report that 5'UTR of cofilin mRNA contains an IRES element, and cofilin is predominantly translated by IRES-mediated mechanism in neurons. Furthermore, we show that IRES-mediated translation of cofilin is required for both axon extension and axonal growth cone steering. Our results provide new insights into the function of IRES-mediated translation in neuronal development.
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Affiliation(s)
- Jung-Hyun Choi
- Department of Life Sciences, Pohang University of Science and Technology, Pohang, Korea
| | - Wei Wang
- Department of Biological Sciences, School of Life Sciences, Ulsan, Korea.,National Creative Research Initiative Center for Proteostasis, Ulsan National Institute of Science and Technology, Ulsan, Korea
| | - Dongkeun Park
- Department of Biological Sciences, School of Life Sciences, Ulsan, Korea.,National Creative Research Initiative Center for Proteostasis, Ulsan National Institute of Science and Technology, Ulsan, Korea
| | - Sung-Hoon Kim
- Division of Integrative Biosciences and Biotechnology, Pohang University of Science and Technology, Pohang, Korea
| | - Kyong-Tai Kim
- Department of Life Sciences, Pohang University of Science and Technology, Pohang, Korea .,Division of Integrative Biosciences and Biotechnology, Pohang University of Science and Technology, Pohang, Korea
| | - Kyung-Tai Min
- Department of Biological Sciences, School of Life Sciences, Ulsan, Korea .,National Creative Research Initiative Center for Proteostasis, Ulsan National Institute of Science and Technology, Ulsan, Korea
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16
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Skruber K, Read TA, Vitriol EA. Reconsidering an active role for G-actin in cytoskeletal regulation. J Cell Sci 2018; 131:131/1/jcs203760. [PMID: 29321224 DOI: 10.1242/jcs.203760] [Citation(s) in RCA: 65] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Globular (G)-actin, the actin monomer, assembles into polarized filaments that form networks that can provide structural support, generate force and organize the cell. Many of these structures are highly dynamic and to maintain them, the cell relies on a large reserve of monomers. Classically, the G-actin pool has been thought of as homogenous. However, recent work has shown that actin monomers can exist in distinct groups that can be targeted to specific networks, where they drive and modify filament assembly in ways that can have profound effects on cellular behavior. This Review focuses on the potential factors that could create functionally distinct pools of actin monomers in the cell, including differences between the actin isoforms and the regulation of G-actin by monomer binding proteins, such as profilin and thymosin β4. Owing to difficulties in studying and visualizing G-actin, our knowledge over the precise role that specific actin monomer pools play in regulating cellular actin dynamics remains incomplete. Here, we discuss some of these unanswered questions and also provide a summary of the methodologies currently available for the imaging of G-actin.
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Affiliation(s)
- Kristen Skruber
- Department of Anatomy and Cell Biology, University of Florida, Gainesville, FL 32610, USA
| | - Tracy-Ann Read
- Department of Anatomy and Cell Biology, University of Florida, Gainesville, FL 32610, USA
| | - Eric A Vitriol
- Department of Anatomy and Cell Biology, University of Florida, Gainesville, FL 32610, USA
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17
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Fu Q, Wu Y. RCAN1 in the inverse association between Alzheimer's disease and cancer. Oncotarget 2017; 9:54-66. [PMID: 29416595 PMCID: PMC5787488 DOI: 10.18632/oncotarget.23094] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2017] [Accepted: 11/17/2017] [Indexed: 01/05/2023] Open
Abstract
The inverse association between Alzheimer’s disease (AD) and cancer has been reported in several population-based studies although both of them are age-related disorders. However, molecular mechanisms of the inverse association remain elusive. Increased expression of regulator of calcineurin 1 (RCAN1) promotes the pathogenesis of AD, while it suppresses cancer growth and progression in many types of cancer. Moreover, aberrant RCAN1 expression is detected in both AD and various types of cancer. It suggests that RCAN1 may play a key role in the inverse association between AD and cancer. In this article, we aim to review the role of RCAN1 in the inverse association and discuss underlying mechanisms, providing an insight into developing a novel approach to treat AD and cancer.
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Affiliation(s)
- Qiang Fu
- Department of General Surgery, Tianjin Medical University General Hospital, Tianjin, China
| | - Yili Wu
- Department of Psychiatry, Jining Medical University, Jining, Shandong, China.,Shandong Key Laboratory of Behavioral Medicine, Jining, Shandong, China.,Collaborative Innovation Center for Birth Defect Research and Transformation of Shandong Province, Jining, Shandong, China
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18
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Peiris H, Keating DJ. The neuronal and endocrine roles of RCAN1 in health and disease. Clin Exp Pharmacol Physiol 2017; 45:377-383. [PMID: 29094385 DOI: 10.1111/1440-1681.12884] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2017] [Revised: 10/18/2017] [Accepted: 10/24/2017] [Indexed: 01/15/2023]
Abstract
The regulator of calcineurin 1 (RCAN1) was first discovered as a gene located on human chromosome 21, expressed in neurons and overexpressed in the brains of Down syndrome individuals. Increased expression of RCAN1 has been linked with not only Down syndrome-associated pathology but also an associated neurological disorder, Alzheimer's Disease, in which neuronal RCAN1 expression is also increased. RCAN1 has additionally been demonstrated to affect other cell types including endocrine cells, with links to the pathogenesis of β-cell dysfunction in type 2 diabetes. The primary functions of RCAN1 relate to the inhibition of the phosphatase calcineurin, and to the regulation of mitochondrial function. Various forms of cellular stress such as reactive oxygen species and hyperglycaemia cause transient increases in RCAN1 expression. The short term (hours to days) induction of RCAN1 expression is generally thought to have a protective effect by regulating the expression of pro-survival genes in multiple cell types, many of which are mediated via the calcineurin/NFAT transcriptional pathway. However, strong evidence also supports the notion that chronic (weeks-years) overexpression of RCAN1 has a detrimental effect on cells and that this may drive pathophysiological changes in neurons and endocrine cells linked to Down syndrome, Alzheimer's Disease and type 2 diabetes. Here we review the evidence related to these roles of RCAN1 in neurons and endocrine cells and their relationship to these human health disorders.
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Affiliation(s)
- Heshan Peiris
- College of Medicine and Public Health and Centre for Neuroscience, Flinders University, Adelaide, SA, Australia
| | - Damien J Keating
- College of Medicine and Public Health and Centre for Neuroscience, Flinders University, Adelaide, SA, Australia
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19
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Bendella H, Rink S, Grosheva M, Sarikcioglu L, Gordon T, Angelov DN. Putative roles of soluble trophic factors in facial nerve regeneration, target reinnervation, and recovery of vibrissal whisking. Exp Neurol 2017; 300:100-110. [PMID: 29104116 DOI: 10.1016/j.expneurol.2017.10.029] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2017] [Revised: 10/25/2017] [Accepted: 10/30/2017] [Indexed: 12/15/2022]
Abstract
It is well-known that, after nerve transection and surgical repair, misdirected regrowth of regenerating motor axons may occur in three ways. The first way is that the axons enter into endoneurial tubes that they did not previously occupy, regenerate through incorrect fascicles and reinnervate muscles that they did not formerly supply. Consequently the activation of these muscles results in inappropriate movements. The second way is that, in contrast with the precise target-directed pathfinding by elongating motor nerves during embryonic development, several axons rather than a single axon grow out from each transected nerve fiber. The third way of misdirection occurs by the intramuscular terminal branching (sprouting) of each regenerating axon to culminate in some polyinnervation of neuromuscular junctions, i.e. reinnervation of junctions by more than a single axon. Presently, "fascicular" or "topographic specificity" cannot be achieved and hence target-directed nerve regeneration is, as yet, unattainable. Nonetheless, motor and sensory reinnervation of appropriate endoneurial tubes does occur and can be promoted by brief nerve electrical stimulation. This review considers the expression of neurotrophic factors in the neuromuscular system and how this expression can promote functional recovery, with emphasis on the whisking of vibrissae on the rat face in relationship to the expression of the factors. Evidence is reviewed for a role of neurotrophic factors as short-range diffusible sprouting stimuli in promoting complete functional recovery of vibrissal whisking in blind Sprague Dawley (SD)/RCS rats but not in SD rats with normal vision, after facial nerve transection and surgical repair. Briefly, a complicated time course of growth factor expression in the nerves and denervated muscles include (1) an early increase in FGF2 and IGF2, (2) reduced NGF between 2 and 14days after nerve transection and surgical repair, (3) a late rise in BDNF and (4) reduced IGF1 protein in the denervated muscles at 28days. These findings suggest that recovery of motor function after peripheral nerve injury is due, at least in part, to a complex regulation of nerve injury-associated neurotrophic factors and cytokines at the neuromuscular junctions of denervated muscles. In particular, the increase of FGF2 and concomittant decrease of NGF during the first week after facial nerve-nerve anastomosis in SD/RCS blind rats may prevent intramuscular axon sprouting and, in turn, reduce poly-innervation of the neuromuscular junction.
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Affiliation(s)
- Habib Bendella
- Department of Neurosurgery, University of Witten/Herdecke, Cologne Merheim Medical Center (CMMC), Cologne, Germany
| | - Svenja Rink
- Department of Prosthetic Dentistry, School of Dental and Oral Medicine, University of Cologne, Germany
| | - Maria Grosheva
- Department of Oto-Rhino-Laryngology, University of Cologne, Germany
| | | | - Tessa Gordon
- Department of Surgery, The Hospital for Sick Children, Toronto, Ontario M5G 1X8, Canada
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20
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Shaw AE, Bamburg JR. Peptide regulation of cofilin activity in the CNS: A novel therapeutic approach for treatment of multiple neurological disorders. Pharmacol Ther 2017; 175:17-27. [PMID: 28232023 PMCID: PMC5466456 DOI: 10.1016/j.pharmthera.2017.02.031] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Cofilin is a ubiquitous protein which cooperates with many other actin-binding proteins in regulating actin dynamics. Cofilin has essential functions in nervous system development including neuritogenesis, neurite elongation, growth cone pathfinding, dendritic spine formation, and the regulation of neurotransmission and spine function, components of synaptic plasticity essential for learning and memory. Cofilin's phosphoregulation is a downstream target of many transmembrane signaling processes, and its misregulation in neurons has been linked in rodent models to many different neurodegenerative and neurological disorders including Alzheimer disease (AD), aggression due to neonatal isolation, autism, manic/bipolar disorder, and sleep deprivation. Cognitive and behavioral deficits of these rodent models have been largely abrogated by modulation of cofilin activity using viral-mediated, genetic, and/or small molecule or peptide therapeutic approaches. Neuropathic pain in rats from sciatic nerve compression has also been reduced by modulating the cofilin pathway within neurons of the dorsal root ganglia. Neuroinflammation, which occurs following cerebral ischemia/reperfusion, but which also accompanies many other neurodegenerative syndromes, is markedly reduced by peptides targeting specific chemokine receptors, which also modulate cofilin activity. Thus, peptide therapeutics offer potential for cost-effective treatment of a wide variety of neurological disorders. Here we discuss some recent results from rodent models using therapeutic peptides with a surprising ability to cross the rodent blood brain barrier and alter cofilin activity in brain. We also offer suggestions as to how neuronal-specific cofilin regulation might be achieved.
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Affiliation(s)
- Alisa E Shaw
- Department of Biochemistry and Molecular Biology, Molecular, Cellular and Integrative Neuroscience Program, Colorado State University, Fort Collins, CO 80523-1870, United States
| | - James R Bamburg
- Department of Biochemistry and Molecular Biology, Molecular, Cellular and Integrative Neuroscience Program, Colorado State University, Fort Collins, CO 80523-1870, United States.
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21
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Catlett TS, Gomez TM. Division of labor in the growth cone by DSCR1. J Cell Biol 2017; 213:407-9. [PMID: 27216257 PMCID: PMC4878096 DOI: 10.1083/jcb.201605012] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2016] [Accepted: 05/05/2016] [Indexed: 01/04/2023] Open
Abstract
Local protein synthesis directs growth cone turning of nascent axons, but mechanisms governing this process within compact, largely autonomous microenvironments remain poorly understood. In this issue, Wang et al. (2016. J. Cell Biol. http://dx.doi.org/10.1083/jcb.201510107) demonstrate that the calcineurin regulator Down syndrome critical region 1 protein modulates both basal neurite outgrowth and growth cone turning.
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Affiliation(s)
- Timothy S Catlett
- Department of Neuroscience, University of Wisconsin, Madison, WI 53706 Cell and Molecular Biology Training Program, University of Wisconsin, Madison, WI 53706
| | - Timothy M Gomez
- Department of Neuroscience, University of Wisconsin, Madison, WI 53706 Cell and Molecular Biology Training Program, University of Wisconsin, Madison, WI 53706
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22
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RCAN1.4 regulates VEGFR-2 internalisation, cell polarity and migration in human microvascular endothelial cells. Angiogenesis 2017; 20:341-358. [PMID: 28271280 PMCID: PMC5511620 DOI: 10.1007/s10456-017-9542-0] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2016] [Accepted: 02/22/2017] [Indexed: 01/13/2023]
Abstract
Regulator of calcineurin 1 (RCAN1) is an endogenous inhibitor of the calcineurin pathway in cells. It is expressed as two isoforms in vertebrates: RCAN1.1 is constitutively expressed in most tissues, whereas transcription of RCAN1.4 is induced by several stimuli that activate the calcineurin-NFAT pathway. RCAN1.4 is highly upregulated in response to VEGF in human endothelial cells in contrast to RCAN1.1 and is essential for efficient endothelial cell migration and tubular morphogenesis. Here, we show that RCAN1.4 has a role in the regulation of agonist-stimulated VEGFR-2 internalisation and establishment of endothelial cell polarity. siRNA-mediated gene silencing revealed that RCAN1 plays a vital role in regulating VEGF-mediated cytoskeletal reorganisation and directed cell migration and sprouting angiogenesis. Adenoviral-mediated overexpression of RCAN1.4 resulted in increased endothelial cell migration. Antisense-mediated morpholino silencing of the zebrafish RCAN1.4 orthologue revealed a disrupted vascular development further confirming a role for the RCAN1.4 isoform in regulating vascular endothelial cell physiology. Our data suggest that RCAN1.4 plays a novel role in regulating endothelial cell migration by establishing endothelial cell polarity in response to VEGF.
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23
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Li W, Choi TW, Ahnn J, Lee SK. Allele-Specific Phenotype Suggests a Possible Stimulatory Activity of RCAN-1 on Calcineurin in Caenorhabditis elegans. Mol Cells 2016; 39:827-833. [PMID: 27871170 PMCID: PMC5125939 DOI: 10.14348/molcells.2016.0222] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2016] [Revised: 10/27/2016] [Accepted: 10/31/2016] [Indexed: 11/27/2022] Open
Abstract
Regulator of calcineurin 1 (RCAN1) binds to calcineurin through the PxIxIT motif, which is evolutionarily conserved. SP repeat phosphorylation in RCAN1 is required for its complete function. The specific interaction between RCAN1 and calcineurin is critical for calcium/calmodulin-dependent regulation of calcineurin serine/threonine phosphatase activity. In this study, we investigated two available deletion rcan-1 mutants in Caenorhabditis elegans, which proceed differently for transcription and translation. We found that rcan-1 may be required for calcineurin activity and possess calcineurin-independent function in body growth and egg-laying behavior. In the genetic background of enhanced calcineurin activity, the rcan-1 mutant expressing a truncated RCAN-1 which retains the calcineurin-binding PxIxIT motif but misses SP repeats stimulated growth, while rcan-1 lack mutant resulted in hyperactive egg-laying suppression. These data suggest rcan-1 has unknown functions independent of calcineurin, and may be a stimulatory calcineurin regulator under certain circumstances.
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Affiliation(s)
- Weixun Li
- Department of Life Science, Hanyang University, Seoul 04763,
Korea
- BK21 PLUS Life Science for BDR Team, Hanyang University, Seoul 04763,
Korea
- Research Institute for Natural Sciences, Hanyang University, Seoul 04763,
Korea
| | - Tae-Woo Choi
- Department of Life Science, Hanyang University, Seoul 04763,
Korea
- BK21 PLUS Life Science for BDR Team, Hanyang University, Seoul 04763,
Korea
- Research Institute for Natural Sciences, Hanyang University, Seoul 04763,
Korea
| | - Joohong Ahnn
- Department of Life Science, Hanyang University, Seoul 04763,
Korea
- BK21 PLUS Life Science for BDR Team, Hanyang University, Seoul 04763,
Korea
- Research Institute for Natural Sciences, Hanyang University, Seoul 04763,
Korea
| | - Sun-Kyung Lee
- Department of Life Science, Hanyang University, Seoul 04763,
Korea
- BK21 PLUS Life Science for BDR Team, Hanyang University, Seoul 04763,
Korea
- Research Institute for Natural Sciences, Hanyang University, Seoul 04763,
Korea
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