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Dermentzaki G, Furlan M, Tanaka I, Leonardi T, Rinchetti P, Passos PMS, Bastos A, Ayala YM, Hanna JH, Przedborski S, Bonanomi D, Pelizzola M, Lotti F. Depletion of Mettl3 in cholinergic neurons causes adult-onset neuromuscular degeneration. Cell Rep 2024; 43:113999. [PMID: 38554281 DOI: 10.1016/j.celrep.2024.113999] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2023] [Revised: 01/25/2024] [Accepted: 03/10/2024] [Indexed: 04/01/2024] Open
Abstract
Motor neuron (MN) demise is a hallmark of several neurodegenerative diseases, including amyotrophic lateral sclerosis (ALS). Post-transcriptional gene regulation can control RNA's fate, and defects in RNA processing are critical determinants of MN degeneration. N6-methyladenosine (m6A) is a post-transcriptional RNA modification that controls diverse aspects of RNA metabolism. To assess the m6A requirement in MNs, we depleted the m6A methyltransferase-like 3 (METTL3) in cells and mice. METTL3 depletion in embryonic stem cell-derived MNs has profound and selective effects on survival and neurite outgrowth. Mice with cholinergic neuron-specific METTL3 depletion display a progressive decline in motor behavior, accompanied by MN loss and muscle denervation, culminating in paralysis and death. Reader proteins convey m6A effects, and their silencing phenocopies METTL3 depletion. Among the m6A targets, we identified transactive response DNA-binding protein 43 (TDP-43) and discovered that its expression is under epitranscriptomic control. Thus, impaired m6A signaling disrupts MN homeostasis and triggers neurodegeneration conceivably through TDP-43 deregulation.
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Affiliation(s)
- Georgia Dermentzaki
- Center for Motor Neuron Biology and Disease, Departments of Pathology & Cell Biology and Neurology, Columbia University, New York, NY, USA
| | - Mattia Furlan
- Center for Genomic Science of IIT@SEMM, Fondazione Istituto Italiano di Tecnologia, Milan, Italy
| | - Iris Tanaka
- Center for Genomic Science of IIT@SEMM, Fondazione Istituto Italiano di Tecnologia, Milan, Italy
| | - Tommaso Leonardi
- Center for Genomic Science of IIT@SEMM, Fondazione Istituto Italiano di Tecnologia, Milan, Italy
| | - Paola Rinchetti
- Center for Motor Neuron Biology and Disease, Departments of Pathology & Cell Biology and Neurology, Columbia University, New York, NY, USA
| | - Patricia M S Passos
- Department of Biochemistry & Molecular Biology, St. Louis University School of Medicine, St. Louis, Missouri, USA
| | - Alliny Bastos
- Department of Biochemistry & Molecular Biology, St. Louis University School of Medicine, St. Louis, Missouri, USA
| | - Yuna M Ayala
- Department of Biochemistry & Molecular Biology, St. Louis University School of Medicine, St. Louis, Missouri, USA
| | - Jacob H Hanna
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot, Israel
| | - Serge Przedborski
- Center for Motor Neuron Biology and Disease, Departments of Pathology & Cell Biology and Neurology, Columbia University, New York, NY, USA; Department of Neuroscience, Columbia University, New York, NY, USA
| | - Dario Bonanomi
- Division of Neuroscience, IRCCS San Raffaele Scientific Institute, Milan, Italy
| | - Mattia Pelizzola
- Center for Genomic Science of IIT@SEMM, Fondazione Istituto Italiano di Tecnologia, Milan, Italy; Department of Biotechnology and Biosciences, University of Milano-Bicocca, Milan, Italy
| | - Francesco Lotti
- Center for Motor Neuron Biology and Disease, Departments of Pathology & Cell Biology and Neurology, Columbia University, New York, NY, USA.
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2
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Bhat GP, Maurizio A, Motta A, Podini P, Diprima S, Malpighi C, Brambilla I, Martins L, Badaloni A, Boselli D, Bianchi F, Pellegatta M, Genua M, Ostuni R, Del Carro U, Taveggia C, de Pretis S, Quattrini A, Bonanomi D. Structured wound angiogenesis instructs mesenchymal barrier compartments in the regenerating nerve. Neuron 2024; 112:209-229.e11. [PMID: 37972594 DOI: 10.1016/j.neuron.2023.10.025] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2023] [Revised: 09/19/2023] [Accepted: 10/18/2023] [Indexed: 11/19/2023]
Abstract
Organ injury stimulates the formation of new capillaries to restore blood supply raising questions about the potential contribution of neoangiogenic vessel architecture to the healing process. Using single-cell mapping, we resolved the properties of endothelial cells that organize a polarized scaffold at the repair site of lesioned peripheral nerves. Transient reactivation of an embryonic guidance program is required to orient neovessels across the wound. Manipulation of this structured angiogenic response through genetic and pharmacological targeting of Plexin-D1/VEGF pathways within an early window of repair has long-term impact on configuration of the nerve stroma. Neovessels direct nerve-resident mesenchymal cells to mold a provisionary fibrotic scar by assembling an orderly system of stable barrier compartments that channel regenerating nerve fibers and shield them from the persistently leaky vasculature. Thus, guided and balanced repair angiogenesis enables the construction of a "bridge" microenvironment conducive for axon regrowth and homeostasis of the regenerated tissue.
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Affiliation(s)
- Ganesh Parameshwar Bhat
- Division of Neuroscience, IRCCS San Raffaele Scientific Institute, via Olgettina 60, 20132 Milan, Italy
| | - Aurora Maurizio
- Center for Omics Sciences, IRCCS San Raffaele Scientific Institute, 20132 Milan, Italy
| | - Alessia Motta
- Division of Neuroscience, IRCCS San Raffaele Scientific Institute, via Olgettina 60, 20132 Milan, Italy
| | - Paola Podini
- Division of Neuroscience, IRCCS San Raffaele Scientific Institute, via Olgettina 60, 20132 Milan, Italy; Institute of Experimental Neurology, IRCCS San Raffaele Scientific Institute, 20132 Milan, Italy
| | - Santo Diprima
- Division of Neuroscience, IRCCS San Raffaele Scientific Institute, via Olgettina 60, 20132 Milan, Italy; Center for Omics Sciences, IRCCS San Raffaele Scientific Institute, 20132 Milan, Italy
| | - Chiara Malpighi
- Division of Neuroscience, IRCCS San Raffaele Scientific Institute, via Olgettina 60, 20132 Milan, Italy
| | - Ilaria Brambilla
- Division of Neuroscience, IRCCS San Raffaele Scientific Institute, via Olgettina 60, 20132 Milan, Italy
| | - Luis Martins
- Division of Neuroscience, IRCCS San Raffaele Scientific Institute, via Olgettina 60, 20132 Milan, Italy
| | - Aurora Badaloni
- Division of Neuroscience, IRCCS San Raffaele Scientific Institute, via Olgettina 60, 20132 Milan, Italy
| | - Daniela Boselli
- FRACTAL-Flow cytometry Resource Advanced Cytometry Technical Applications Laboratory, IRCCS San Raffaele Scientific Institute, 20132 Milan, Italy
| | - Francesca Bianchi
- Division of Neuroscience, IRCCS San Raffaele Scientific Institute, via Olgettina 60, 20132 Milan, Italy
| | - Marta Pellegatta
- Division of Neuroscience, IRCCS San Raffaele Scientific Institute, via Olgettina 60, 20132 Milan, Italy
| | - Marco Genua
- San Raffaele Telethon Institute for Gene therapy (SR-Tiget), IRCCS San Raffaele Scientific Institute, 20132 Milan, Italy
| | - Renato Ostuni
- San Raffaele Telethon Institute for Gene therapy (SR-Tiget), IRCCS San Raffaele Scientific Institute, 20132 Milan, Italy
| | - Ubaldo Del Carro
- Division of Neuroscience, IRCCS San Raffaele Scientific Institute, via Olgettina 60, 20132 Milan, Italy
| | - Carla Taveggia
- Division of Neuroscience, IRCCS San Raffaele Scientific Institute, via Olgettina 60, 20132 Milan, Italy
| | - Stefano de Pretis
- Center for Omics Sciences, IRCCS San Raffaele Scientific Institute, 20132 Milan, Italy
| | - Angelo Quattrini
- Division of Neuroscience, IRCCS San Raffaele Scientific Institute, via Olgettina 60, 20132 Milan, Italy; Institute of Experimental Neurology, IRCCS San Raffaele Scientific Institute, 20132 Milan, Italy
| | - Dario Bonanomi
- Division of Neuroscience, IRCCS San Raffaele Scientific Institute, via Olgettina 60, 20132 Milan, Italy.
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3
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Martins LF, Brambilla I, Motta A, de Pretis S, Bhat GP, Badaloni A, Malpighi C, Amin ND, Imai F, Almeida RD, Yoshida Y, Pfaff SL, Bonanomi D. Motor neurons use push-pull signals to direct vascular remodeling critical for their connectivity. Neuron 2022; 110:4090-4107.e11. [PMID: 36240771 PMCID: PMC10316999 DOI: 10.1016/j.neuron.2022.09.021] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2022] [Revised: 07/19/2022] [Accepted: 09/15/2022] [Indexed: 11/06/2022]
Abstract
The nervous system requires metabolites and oxygen supplied by the neurovascular network, but this necessitates close apposition of neurons and endothelial cells. We find motor neurons attract vessels with long-range VEGF signaling, but endothelial cells in the axonal pathway are an obstacle for establishing connections with muscles. It is unclear how this paradoxical interference from heterotypic neurovascular contacts is averted. Through a mouse mutagenesis screen, we show that Plexin-D1 receptor is required in endothelial cells for development of neuromuscular connectivity. Motor neurons release Sema3C to elicit short-range repulsion via Plexin-D1, thus displacing endothelial cells that obstruct axon growth. When this signaling pathway is disrupted, epaxial motor neurons are blocked from reaching their muscle targets and concomitantly vascular patterning in the spinal cord is altered. Thus, an integrative system of opposing push-pull cues ensures detrimental axon-endothelial encounters are avoided while enabling vascularization within the nervous system and along peripheral nerves.
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Affiliation(s)
- Luis F Martins
- San Raffaele Scientific Institute, Division of Neuroscience, via Olgettina 60, 20132 Milan, Italy; CNC, Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra 3004-504, Portugal
| | - Ilaria Brambilla
- San Raffaele Scientific Institute, Division of Neuroscience, via Olgettina 60, 20132 Milan, Italy
| | - Alessia Motta
- San Raffaele Scientific Institute, Division of Neuroscience, via Olgettina 60, 20132 Milan, Italy
| | - Stefano de Pretis
- San Raffaele Scientific Institute, Division of Neuroscience, via Olgettina 60, 20132 Milan, Italy; Center for Omics Sciences, San Raffaele Scientific Institute, Milan, Italy
| | - Ganesh Parameshwar Bhat
- San Raffaele Scientific Institute, Division of Neuroscience, via Olgettina 60, 20132 Milan, Italy
| | - Aurora Badaloni
- San Raffaele Scientific Institute, Division of Neuroscience, via Olgettina 60, 20132 Milan, Italy
| | - Chiara Malpighi
- San Raffaele Scientific Institute, Division of Neuroscience, via Olgettina 60, 20132 Milan, Italy
| | - Neal D Amin
- Gene Expression Laboratory, Salk Institute for Biological Studies, 10010 North Torrey Pines, La Jolla, CA 92037, USA
| | - Fumiyasu Imai
- Burke Neurological Institute, White Plains, NY 10605, USA; Brain and Mind Research Institute, Weill Cornell Medicine, New York, NY 10065, USA
| | - Ramiro D Almeida
- CNC, Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra 3004-504, Portugal; iBiMED - Institute of Biomedicine, Department of Medical Sciences, University of Aveiro, Aveiro 3810-193, Portugal
| | - Yutaka Yoshida
- Burke Neurological Institute, White Plains, NY 10605, USA; Brain and Mind Research Institute, Weill Cornell Medicine, New York, NY 10065, USA; Neural Circuit Unit, Okinawa Institute of Science and Technology Graduate University, Okinawa, Japan
| | - Samuel L Pfaff
- Gene Expression Laboratory, Salk Institute for Biological Studies, 10010 North Torrey Pines, La Jolla, CA 92037, USA.
| | - Dario Bonanomi
- San Raffaele Scientific Institute, Division of Neuroscience, via Olgettina 60, 20132 Milan, Italy.
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4
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Vieira JR, Shah B, Dupraz S, Paredes I, Himmels P, Schermann G, Adler H, Motta A, Gärtner L, Navarro-Aragall A, Ioannou E, Dyukova E, Bonnavion R, Fischer A, Bonanomi D, Bradke F, Ruhrberg C, Ruiz de Almodóvar C. Endothelial PlexinD1 signaling instructs spinal cord vascularization and motor neuron development. Neuron 2022; 110:4074-4089.e6. [PMID: 36549270 PMCID: PMC9796814 DOI: 10.1016/j.neuron.2022.12.005] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2022] [Revised: 11/04/2022] [Accepted: 12/03/2022] [Indexed: 12/24/2022]
Abstract
How the vascular and neural compartment cooperate to achieve such a complex and highly specialized structure as the central nervous system is still unclear. Here, we reveal a crosstalk between motor neurons (MNs) and endothelial cells (ECs), necessary for the coordinated development of MNs. By analyzing cell-to-cell interaction profiles of the mouse developing spinal cord, we uncovered semaphorin 3C (Sema3C) and PlexinD1 as a communication axis between MNs and ECs. Using cell-specific knockout mice and in vitro assays, we demonstrate that removal of Sema3C in MNs, or its receptor PlexinD1 in ECs, results in premature and aberrant vascularization of MN columns. Those vascular defects impair MN axon exit from the spinal cord. Impaired PlexinD1 signaling in ECs also causes MN maturation defects at later stages. This study highlights the importance of a timely and spatially controlled communication between MNs and ECs for proper spinal cord development.
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Affiliation(s)
- José Ricardo Vieira
- European Center for Angioscience, Medical Faculty Mannheim, Heidelberg University, Ludolf-Krehl-Straße 13-17, 68167 Mannheim, Germany,Faculty of Biosciences, Heidelberg University, Im Neuenheimer 234, 69120 Heidelberg, Germany
| | - Bhavin Shah
- European Center for Angioscience, Medical Faculty Mannheim, Heidelberg University, Ludolf-Krehl-Straße 13-17, 68167 Mannheim, Germany
| | - Sebastian Dupraz
- Institute for Neurovascular Cell Biology, University Hospital Bonn, Venusberg-Campus 1, 53127 Bonn, Germany
| | - Isidora Paredes
- European Center for Angioscience, Medical Faculty Mannheim, Heidelberg University, Ludolf-Krehl-Straße 13-17, 68167 Mannheim, Germany,Faculty of Biosciences, Heidelberg University, Im Neuenheimer 234, 69120 Heidelberg, Germany
| | - Patricia Himmels
- Faculty of Biosciences, Heidelberg University, Im Neuenheimer 234, 69120 Heidelberg, Germany
| | - Géza Schermann
- European Center for Angioscience, Medical Faculty Mannheim, Heidelberg University, Ludolf-Krehl-Straße 13-17, 68167 Mannheim, Germany,Institute for Neurovascular Cell Biology, University Hospital Bonn, Venusberg-Campus 1, 53127 Bonn, Germany
| | - Heike Adler
- European Center for Angioscience, Medical Faculty Mannheim, Heidelberg University, Ludolf-Krehl-Straße 13-17, 68167 Mannheim, Germany
| | - Alessia Motta
- San Raffaele Scientific Institute, Division of Neuroscience, via Olgettina 60, 20132 Milan, Italy
| | - Lea Gärtner
- European Center for Angioscience, Medical Faculty Mannheim, Heidelberg University, Ludolf-Krehl-Straße 13-17, 68167 Mannheim, Germany
| | - Ariadna Navarro-Aragall
- UCL Institute of Ophthalmology, University College London, 11-43 Bath Street, EC1V 9EL London, UK
| | - Elena Ioannou
- UCL Institute of Ophthalmology, University College London, 11-43 Bath Street, EC1V 9EL London, UK
| | - Elena Dyukova
- Max-Planck-Institute for Heart and Lung Research, Ludwigstr. 43, 61231 Bad Nauheim, Germany
| | - Remy Bonnavion
- Max-Planck-Institute for Heart and Lung Research, Ludwigstr. 43, 61231 Bad Nauheim, Germany
| | - Andreas Fischer
- Department of Clinical Chemistry, University Medical Center Göttingen, Robert-Koch-Straße 40, 37075 Göttingen, Germany,Division Vascular Signaling and Cancer, German Cancer Research Center Heidelberg, Im Neuenheimer Feld 280, 69120 Heidelberg, Germany
| | - Dario Bonanomi
- San Raffaele Scientific Institute, Division of Neuroscience, via Olgettina 60, 20132 Milan, Italy
| | - Frank Bradke
- Laboratory of Axon Growth and Regeneration, German Center for Neurodegenerative Diseases (DZNE), Venusberg Campus 1/99, 53127 Bonn, Germany
| | - Christiana Ruhrberg
- UCL Institute of Ophthalmology, University College London, 11-43 Bath Street, EC1V 9EL London, UK
| | - Carmen Ruiz de Almodóvar
- European Center for Angioscience, Medical Faculty Mannheim, Heidelberg University, Ludolf-Krehl-Straße 13-17, 68167 Mannheim, Germany; Institute for Neurovascular Cell Biology, University Hospital Bonn, Venusberg-Campus 1, 53127 Bonn, Germany; Schlegel Chair for Neurovascular Cell Biology, University of Bonn, Venusberg-Campus 1, 53127 Bonn, Germany.
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Amin ND, Senturk G, Costaguta G, Driscoll S, O'Leary B, Bonanomi D, Pfaff SL. A hidden threshold in motor neuron gene networks revealed by modulation of miR-218 dose. Neuron 2021; 109:3252-3267.e6. [PMID: 34450025 DOI: 10.1016/j.neuron.2021.07.028] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2021] [Revised: 06/01/2021] [Accepted: 07/29/2021] [Indexed: 10/20/2022]
Abstract
Disruption of homeostatic microRNA (miRNA) expression levels is known to cause human neuropathology. However, the gene regulatory and phenotypic effects of altering a miRNA's in vivo abundance (rather than its binary gain or loss) are not well understood. By genetic combination, we generated an allelic series of mice expressing varying levels of miR-218, a motor neuron-selective gene regulator associated with motor neuron disease. Titration of miR-218 cellular dose unexpectedly revealed complex, non-ratiometric target mRNA dose responses and distinct gene network outputs. A non-linearly responsive regulon exhibited a steep miR-218 dose-dependent threshold in repression that, when crossed, resulted in severe motor neuron synaptic failure and death. This work demonstrates that a miRNA can govern distinct gene network outputs at different expression levels and that miRNA-dependent phenotypes emerge at particular dose ranges because of hidden regulatory inflection points of their underlying gene networks.
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Affiliation(s)
- Neal D Amin
- Gene Expression Laboratory, Salk Institute for Biological Studies, 10010 North Torrey Pines Road, La Jolla, CA 92037, USA.
| | - Gokhan Senturk
- Gene Expression Laboratory, Salk Institute for Biological Studies, 10010 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Giancarlo Costaguta
- Gene Expression Laboratory, Salk Institute for Biological Studies, 10010 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Shawn Driscoll
- Gene Expression Laboratory, Salk Institute for Biological Studies, 10010 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Brendan O'Leary
- Gene Expression Laboratory, Salk Institute for Biological Studies, 10010 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Dario Bonanomi
- Gene Expression Laboratory, Salk Institute for Biological Studies, 10010 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Samuel L Pfaff
- Gene Expression Laboratory, Salk Institute for Biological Studies, 10010 North Torrey Pines Road, La Jolla, CA 92037, USA.
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Bonanomi D, Valenza F, Chivatakarn O, Sternfeld MJ, Driscoll SP, Aslanian A, Lettieri K, Gullo M, Badaloni A, Lewcock JW, Hunter T, Pfaff SL. p190RhoGAP Filters Competing Signals to Resolve Axon Guidance Conflicts. Neuron 2019; 102:602-620.e9. [PMID: 30902550 PMCID: PMC8608148 DOI: 10.1016/j.neuron.2019.02.034] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2018] [Revised: 12/05/2018] [Accepted: 02/19/2019] [Indexed: 12/21/2022]
Abstract
The rich functional diversity of the nervous system is founded in the specific connectivity of the underlying neural circuitry. Neurons are often preprogrammed to respond to multiple axon guidance signals because they use sequential guideposts along their pathways, but this necessitates a strict spatiotemporal regulation of intracellular signaling to ensure the cues are detected in the correct order. We performed a mouse mutagenesis screen and identified the Rho GTPase antagonist p190RhoGAP as a critical regulator of motor axon guidance. Rather than acting as a compulsory signal relay, p190RhoGAP uses a non-conventional GAP-independent mode to transiently suppress attraction to Netrin-1 while motor axons exit the spinal cord. Once in the periphery, a subset of axons requires p190RhoGAP-mediated inhibition of Rho signaling to target specific muscles. Thus, the multifunctional activity of p190RhoGAP emerges from its modular design. Our findings reveal a cell-intrinsic gate that filters conflicting signals, establishing temporal windows of signal detection.
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Affiliation(s)
- Dario Bonanomi
- Gene Expression Laboratory and the Howard Hughes Medical Institute, Salk Institute for Biological Studies, 10010 North Torrey Pines, La Jolla, CA 92037, USA; San Raffaele Scientific Institute, Division of Neuroscience, via Olgettina 60, 20132 Milan, Italy.
| | - Fabiola Valenza
- San Raffaele Scientific Institute, Division of Neuroscience, via Olgettina 60, 20132 Milan, Italy
| | - Onanong Chivatakarn
- Gene Expression Laboratory and the Howard Hughes Medical Institute, Salk Institute for Biological Studies, 10010 North Torrey Pines, La Jolla, CA 92037, USA
| | - Matthew J Sternfeld
- Gene Expression Laboratory and the Howard Hughes Medical Institute, Salk Institute for Biological Studies, 10010 North Torrey Pines, La Jolla, CA 92037, USA
| | - Shawn P Driscoll
- Gene Expression Laboratory and the Howard Hughes Medical Institute, Salk Institute for Biological Studies, 10010 North Torrey Pines, La Jolla, CA 92037, USA
| | - Aaron Aslanian
- Molecular and Cell Biology Laboratory, Salk Institute for Biological Studies, 10010 North Torrey Pines, La Jolla, CA 92037, USA
| | - Karen Lettieri
- Gene Expression Laboratory and the Howard Hughes Medical Institute, Salk Institute for Biological Studies, 10010 North Torrey Pines, La Jolla, CA 92037, USA
| | - Miriam Gullo
- Gene Expression Laboratory and the Howard Hughes Medical Institute, Salk Institute for Biological Studies, 10010 North Torrey Pines, La Jolla, CA 92037, USA
| | - Aurora Badaloni
- San Raffaele Scientific Institute, Division of Neuroscience, via Olgettina 60, 20132 Milan, Italy
| | - Joseph W Lewcock
- Gene Expression Laboratory and the Howard Hughes Medical Institute, Salk Institute for Biological Studies, 10010 North Torrey Pines, La Jolla, CA 92037, USA
| | - Tony Hunter
- Molecular and Cell Biology Laboratory, Salk Institute for Biological Studies, 10010 North Torrey Pines, La Jolla, CA 92037, USA
| | - Samuel L Pfaff
- Gene Expression Laboratory and the Howard Hughes Medical Institute, Salk Institute for Biological Studies, 10010 North Torrey Pines, La Jolla, CA 92037, USA.
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7
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Valenza F, Cittaro D, Stupka E, Biancolini D, Patricelli MG, Bonanomi D, Lazarević D. A novel truncating variant of GLI2 associated with Culler-Jones syndrome impairs Hedgehog signalling. PLoS One 2019; 14:e0210097. [PMID: 30629636 PMCID: PMC6328167 DOI: 10.1371/journal.pone.0210097] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2018] [Accepted: 12/16/2018] [Indexed: 12/30/2022] Open
Abstract
Background GLI2 encodes for a transcription factor that controls the expression of several genes in the Hedgehog pathway. Mutations in GLI2 have been described as causative of a spectrum of clinical phenotypes, notably holoprosencephaly, hypopituitarism and postaxial polydactyl. Methods In order to identify causative genetic variant, we performed exome sequencing of a trio from an Italian family with multiple affected individuals presenting clinical phenotypes in the Culler-Jones syndrome spectrum. We performed a series of cell-based assays to test the functional properties of mutant GLI2. Results Here we report a novel deletion c.3493delC (p.P1167LfsX52) in the C-terminal activation domain of GLI2. Functional assays confirmed the pathogenicity of the identified variant and revealed a dominant-negative effect of mutant GLI2 on Hedgehog signalling. Conclusions Our results highlight the variable clinical manifestation of GLI2 mutations and emphasize the value of functional characterisation of novel gene variants to assist genetic counselling and diagnosis.
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Affiliation(s)
- Fabiola Valenza
- Molecular Neurobiology Laboratory, Division of Neuroscience, IRCSS San Raffaele Scientific Institute, Milan, Italy
| | - Davide Cittaro
- Centre for Translational Genomics and Bioinformatics, IRCSS San Raffaele Scientific Institute, Milan, Italy
| | - Elia Stupka
- Centre for Translational Genomics and Bioinformatics, IRCSS San Raffaele Scientific Institute, Milan, Italy
- Dana-Farber Cancer Institute, Harvard Medical School, Boston, MA, United States of America
| | - Donatella Biancolini
- Centre for Translational Genomics and Bioinformatics, IRCSS San Raffaele Scientific Institute, Milan, Italy
| | | | - Dario Bonanomi
- Molecular Neurobiology Laboratory, Division of Neuroscience, IRCSS San Raffaele Scientific Institute, Milan, Italy
| | - Dejan Lazarević
- Centre for Translational Genomics and Bioinformatics, IRCSS San Raffaele Scientific Institute, Milan, Italy
- * E-mail:
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8
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Kumar H, Choi H, Jo MJ, Joshi HP, Muttigi M, Bonanomi D, Kim SB, Ban E, Kim A, Lee SH, Kim KT, Sohn S, Zeng X, Han I. Neutrophil elastase inhibition effectively rescued angiopoietin-1 decrease and inhibits glial scar after spinal cord injury. Acta Neuropathol Commun 2018; 6:73. [PMID: 30086801 PMCID: PMC6080383 DOI: 10.1186/s40478-018-0576-3] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2018] [Accepted: 07/23/2018] [Indexed: 01/13/2023] Open
Abstract
After spinal cord injury (SCI), neutrophil elastase (NE) released at injury site disrupts vascular endothelium integrity and stabilization. Angiopoietins (ANGPTs) are vascular growth factors that play an important role in vascular stabilization. We hypothesized that neutrophil elastase is one of the key determinants of vascular endothelium disruption/destabilization and affects angiopoietins expression after spinal cord injury. To test this, tubule formation and angiopoietins expression were assessed in endothelial cells exposed to different concentrations of recombinant neutropil elastase. Then, the expression of angiopoietin-1, angiopoietin-2, and neutrophil elastase was determined at 3 h and at 1, 3, 5, 7, 14, 21, and 28 days in a clinically relevant model of moderate compression (35 g for 5 min at T10) spinal cord injury. A dichotomy between the levels of angiopoietin-1 and angiopoietin-2 was observed; thus, we utilized a specific neutrophil elastase inhibitor (sivelestat sodium; 30 mg/kg, i.p., b.i.d.) after spinal cord injury. The expression levels of neutropil elastase and angiopoietin-2 increased, and that of angiopoietin-1 decreased after spinal cord injury in rats. The sivelestat regimen, optimized via a pharmacokinetics study, had potent effects on vascular stabilization by upregulating angiopoietin-1 via the AKT pathway and preventing tight junction protein degradation. Moreover, sivelestat attenuated the levels of inflammatory cytokines and chemokines after spinal cord injury and hence subsequently alleviated secondary damage observed as a reduction in glial scar formation and the promotion of blood vessel formation and stabilization. As a result, hindlimb locomotor function significantly recovered in the sivelestat-treated animals as determined by the Basso, Beattie, and Bresnahan scale and footprint analyses. Furthermore, sivelestat treatment attenuated neuropathic pain as assessed by responses to von Frey filaments after spinal cord injury. Thus, our result suggests that inhibiting neutropil elastase by administration of sivelestat is a promising therapeutic strategy to inhibit glial scar and promote functional recovery by upregulating angiopoietin-1 after spinal cord injury.
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Affiliation(s)
- Hemant Kumar
- Department of Neurosurgery, CHA University School of Medicine, CHA Bundang Medical Center, Seongnam-si, Gyeonggi-do, 13496, Republic of Korea
| | - Hyemin Choi
- Department of Neurosurgery, CHA University School of Medicine, CHA Bundang Medical Center, Seongnam-si, Gyeonggi-do, 13496, Republic of Korea
| | - Min-Jae Jo
- Department of Neurosurgery, CHA University School of Medicine, CHA Bundang Medical Center, Seongnam-si, Gyeonggi-do, 13496, Republic of Korea
| | - Hari Prasad Joshi
- Department of Neurosurgery, CHA University School of Medicine, CHA Bundang Medical Center, Seongnam-si, Gyeonggi-do, 13496, Republic of Korea
| | - Manjunatha Muttigi
- Department of Biomedical Science, CHA University, Seongnam-si, Gyeonggi-do, Republic of Korea
| | - Dario Bonanomi
- Molecular Neurobiology Laboratory, Division of Neuroscience, San Raffaele Scientific Institute, Milan, Italy
| | - Sung Bum Kim
- Department of Neurosurgery, Kyung Hee University, Dongdaemun-gu, Seoul, 02447, Republic of Korea
| | - Eunmi Ban
- College of Pharmacy, CHA University, Seongnam-si, Gyeonggi-do, Republic of Korea
| | - Aeri Kim
- College of Pharmacy, CHA University, Seongnam-si, Gyeonggi-do, Republic of Korea
| | - Soo-Hong Lee
- Department of Biomedical Science, CHA University, Seongnam-si, Gyeonggi-do, Republic of Korea
| | - Kyoung-Tae Kim
- Department of Neurosurgery, Kyungpook National University Hospital, Kyungpook National University, 130, Dongdeok-ro, Jung-gu, Daegu, 41944, Republic of Korea
- Department of Neurosurgery, School of Medicine,Kyungpook National University, 130, Dongdeok-ro, Jung-gu, Daegu, 41944, Republic of Korea
| | - Seil Sohn
- Department of Neurosurgery, CHA University School of Medicine, CHA Bundang Medical Center, Seongnam-si, Gyeonggi-do, 13496, Republic of Korea
| | - Xiang Zeng
- Department of Histology and Embryology, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, 510080, Guangdong Province, China.
| | - Inbo Han
- Department of Neurosurgery, CHA University School of Medicine, CHA Bundang Medical Center, Seongnam-si, Gyeonggi-do, 13496, Republic of Korea.
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9
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Abstract
Motor neurons of the spinal cord are responsible for the assembly of neuromuscular connections indispensable for basic locomotion and skilled movements. A precise spatial relationship exists between the position of motor neuron cell bodies in the spinal cord and the course of their axonal projections to peripheral muscle targets. Motor neuron innervation of the vertebrate limb is a prime example of this topographic organization and by virtue of its accessibility and predictability has provided access to fundamental principles of motor system development and neuronal guidance. The seemingly basic binary map established by genetically defined motor neuron subtypes that target muscles in the limb is directed by a surprisingly large number of directional cues. Rather than being simply redundant, these converging signaling pathways are hierarchically linked and cooperate to increase the fidelity of axon pathfinding decisions. A current priority is to determine how multiple guidance signals are integrated by individual growth cones and how they synergize to delineate class-specific axonal trajectories.
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Affiliation(s)
- Dario Bonanomi
- Molecular Neurobiology Laboratory, Division of Neuroscience, San Raffaele Scientific Institute, Milan, Italy.
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10
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Pozzi L, Valenza F, Mosca L, Dal Mas A, Domi T, Romano A, Tarlarini C, Falzone YM, Tremolizzo L, Sorarù G, Cerri F, Ferraro PM, Basaia S, Agosta F, Fazio R, Comola M, Comi G, Ferrari M, Quattrini A, Lunetta C, Penco S, Bonanomi D, Carrera P, Riva N. TBK1 mutations in Italian patients with amyotrophic lateral sclerosis: genetic and functional characterisation. J Neurol Neurosurg Psychiatry 2017; 88:869-875. [PMID: 28822984 PMCID: PMC5629935 DOI: 10.1136/jnnp-2017-316174] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/31/2017] [Revised: 05/31/2017] [Accepted: 06/23/2017] [Indexed: 01/02/2023]
Abstract
BACKGROUND TANK-binding kinase 1 (TBK1) gene has been recently identified as a causative gene of amyotrophic lateral sclerosis (ALS). METHODS We sequenced the TBK1 gene in a cohort of 154 Italian patients with ALS with unclear genetic aetiology. We subsequently assessed the pathogenic potential of novel identified TBK1 variants using functional in vitro studies: expression, targeting and activity were evaluated in patient-derived fibroblasts and in cells transfected with mutated-TBK1 plasmids. RESULTS We identified novel genomic TBK1 variants including two loss-of-function (LoF) (p.Leu59Phefs*16 and c.358+5G>A), two missense (p.Asp118Asn and p.Ile397Thr) and one intronic variant (c.1644-5_1644-2delAATA), in addition to two previously reported pathogenetic missense variants (p.Lys291Glu and p.Arg357Gln). Functional studies in patient-derived fibroblasts revealed that the c.358+5G>A causes aberrant pre-mRNA processing leading TBK1 haploinsufficiency. Biochemical studies in cellular models showed that the truncating variant p.Leu59Phefs*16 abolishes TBK1 protein expression, whereas the p.Asp118Asn variant severely impairs TBK1 phosphorylation activity. Conversely, the p.Ile397Thr variant displayed enhanced phosphorylation activity, whose biological relevance is not clear. CONCLUSION The observed frequency of TBK1 LoF variants was 1.3% (2/154), increasing up to 3.2% (5/154) by taking into account also the functional missense variants that we were able to classify as potentially pathogenic, supporting the relevance of TBK1 in the Italian population with ALS.
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Affiliation(s)
- Laura Pozzi
- Neuropathology Unit, Institute of Experimental Neurology (INSPE), Division of Neuroscience, San Raffaele Scientific Institute, Milan, Italy
| | - Fabiola Valenza
- Molecular Neurobiology Laboratory, Division of Neuroscience, San Raffaele Scientific Institute, Milan, Italy
| | - Lorena Mosca
- Medical Genetic Unit, Department of Laboratory Medicine, Niguarda Hospital, Milan, Italy
| | - Andrea Dal Mas
- Molecular Neurobiology Laboratory, Division of Neuroscience, San Raffaele Scientific Institute, Milan, Italy
| | - Teuta Domi
- Neuropathology Unit, Institute of Experimental Neurology (INSPE), Division of Neuroscience, San Raffaele Scientific Institute, Milan, Italy
| | - Alessandro Romano
- Neuropathology Unit, Institute of Experimental Neurology (INSPE), Division of Neuroscience, San Raffaele Scientific Institute, Milan, Italy
| | - Claudia Tarlarini
- Medical Genetic Unit, Department of Laboratory Medicine, Niguarda Hospital, Milan, Italy
| | - Yuri Matteo Falzone
- Neuropathology Unit, Institute of Experimental Neurology (INSPE), Division of Neuroscience, San Raffaele Scientific Institute, Milan, Italy.,Department of Neurology, Institute of Experimental Neurology (INSPE), Division of Neuroscience, San Raffaele Scientific Institute, Milan, Italy
| | - Lucio Tremolizzo
- Neurology Unit, "San Gerardo" Hospital and University of Milano-Bicocca, Monza, Italy
| | - Gianni Sorarù
- Department of Neurosciences, Neuromuscular Center, University of Padova, Padua, Italy
| | - Federica Cerri
- Neuropathology Unit, Institute of Experimental Neurology (INSPE), Division of Neuroscience, San Raffaele Scientific Institute, Milan, Italy.,Department of Neurology, Institute of Experimental Neurology (INSPE), Division of Neuroscience, San Raffaele Scientific Institute, Milan, Italy
| | - Pilar M Ferraro
- Neuroimaging Research Unit, Department of Neurology, Institute of Experimental Neurology (INSPE), Division of Neuroscience, San Raffaele Scientific Institute, Milan, Italy
| | - Silvia Basaia
- Neuroimaging Research Unit, Department of Neurology, Institute of Experimental Neurology (INSPE), Division of Neuroscience, San Raffaele Scientific Institute, Milan, Italy
| | - Federica Agosta
- Neuroimaging Research Unit, Department of Neurology, Institute of Experimental Neurology (INSPE), Division of Neuroscience, San Raffaele Scientific Institute, Milan, Italy
| | - Raffaella Fazio
- Department of Neurology, Institute of Experimental Neurology (INSPE), Division of Neuroscience, San Raffaele Scientific Institute, Milan, Italy
| | - Mauro Comola
- Department of Neurology, Institute of Experimental Neurology (INSPE), Division of Neuroscience, San Raffaele Scientific Institute, Milan, Italy
| | - Giancarlo Comi
- Department of Neurology, Institute of Experimental Neurology (INSPE), Division of Neuroscience, San Raffaele Scientific Institute, Milan, Italy.,Università Vita e Salute San Raffaele, Milan, Italy
| | - Maurizio Ferrari
- Università Vita e Salute San Raffaele, Milan, Italy.,Division of Genetics and Cell Biology, Unit of Genomics for Human Disease Diagnosis, San Raffaele Scientific Institute, Milan, Italy
| | - Angelo Quattrini
- Neuropathology Unit, Institute of Experimental Neurology (INSPE), Division of Neuroscience, San Raffaele Scientific Institute, Milan, Italy
| | - Christian Lunetta
- NEuroMuscular Omnicentre (NEMO), Fondazione Serena Onlus, Milan, Italy
| | - Silvana Penco
- Medical Genetic Unit, Department of Laboratory Medicine, Niguarda Hospital, Milan, Italy
| | - Dario Bonanomi
- Molecular Neurobiology Laboratory, Division of Neuroscience, San Raffaele Scientific Institute, Milan, Italy
| | - Paola Carrera
- Division of Genetics and Cell Biology, Unit of Genomics for Human Disease Diagnosis, San Raffaele Scientific Institute, Milan, Italy
| | - Nilo Riva
- Neuropathology Unit, Institute of Experimental Neurology (INSPE), Division of Neuroscience, San Raffaele Scientific Institute, Milan, Italy.,Department of Neurology, Institute of Experimental Neurology (INSPE), Division of Neuroscience, San Raffaele Scientific Institute, Milan, Italy
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11
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Sternfeld MJ, Hinckley CA, Moore NJ, Pankratz MT, Hilde KL, Driscoll SP, Hayashi M, Amin ND, Bonanomi D, Gifford WD, Sharma K, Goulding M, Pfaff SL. Speed and segmentation control mechanisms characterized in rhythmically-active circuits created from spinal neurons produced from genetically-tagged embryonic stem cells. eLife 2017; 6. [PMID: 28195039 PMCID: PMC5308898 DOI: 10.7554/elife.21540] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2016] [Accepted: 01/16/2017] [Indexed: 12/31/2022] Open
Abstract
Flexible neural networks, such as the interconnected spinal neurons that control distinct motor actions, can switch their activity to produce different behaviors. Both excitatory (E) and inhibitory (I) spinal neurons are necessary for motor behavior, but the influence of recruiting different ratios of E-to-I cells remains unclear. We constructed synthetic microphysical neural networks, called circuitoids, using precise combinations of spinal neuron subtypes derived from mouse stem cells. Circuitoids of purified excitatory interneurons were sufficient to generate oscillatory bursts with properties similar to in vivo central pattern generators. Inhibitory V1 neurons provided dual layers of regulation within excitatory rhythmogenic networks - they increased the rhythmic burst frequency of excitatory V3 neurons, and segmented excitatory motor neuron activity into sub-networks. Accordingly, the speed and pattern of spinal circuits that underlie complex motor behaviors may be regulated by quantitatively gating the intra-network cellular activity ratio of E-to-I neurons. DOI:http://dx.doi.org/10.7554/eLife.21540.001 The nerve cells or neurons within an animal’s nervous system connect with one another like the wires in a complex circuit. Each neuron can send and receive signals and a major challenge in neuroscience is to understand how these circuits of neurons behave. To do this, researchers often use genetic tools and computer modeling to map the connections between the cells in a nervous system. However, it remains difficult to predict how an input signal will appear at the output after it passes through a network made of different types of neuron. Brains contain many networks of interconnected neurons. Some of these networks send signals with a rhythmic pattern and typically drive repetitive movements such as breathing and walking. The networks are called central pattern generators (or CPGs for short). They contain both excitatory and inhibitory neurons and can generate rhythmic activity without any additional input. Nevertheless CPGs are not rigid, but can flexibly control when and how fast the muscles are activated to suit the animal's needs. It is thought the circuits are flexible because of the way excitatory and inhibitory neurons interact, but it is not known how these interactions define the behavior of the circuit. Sternfeld et al. have now developed a new method to examine how the neurons that make up a circuit influence its activity. First, embryonic stem cells from mice were coaxed to develop into a number of subtypes of both excitatory and inhibitory neurons in the laboratory. These neurons were used to grow networks of neurons in a dish, named “circuitoids”. The precise combination of subtypes of neuron was deliberately varied between each circuitoid, and Sternfeld et al. then studied how the different circuitoids behaved. Several subtypes of excitatory neurons showed rhythmic bursts of activity, just like simple CPGs. Moreover, the ratio of excitatory to inhibitory neurons in the circuitoids was critical for establishing how fast and synchronized the bursts of activity were across the network. It is possible that the brain also uses this simple strategy of varying the ratio of excitatory to inhibitory neurons in circuits of neurons to generate complex, yet highly flexible, circuits with rhythmic activity. Further work will be needed to test this idea. Finally, other researchers will hopefully be able to use this new approach to construct circuitoids and learn more about how the brain generates and controls rhythmic activity. It might also be possible to one-day transplant similar circuitoids into people to repair injured or diseased parts of a nervous system, or use circuitoids that resemble specific neurological disorders to screen for new treatments. DOI:http://dx.doi.org/10.7554/eLife.21540.002
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Affiliation(s)
- Matthew J Sternfeld
- Gene Expression Laboratory, Howard Hughes Medical Institute, Salk Institute for Biological Studies, La Jolla, United States.,Biological Sciences Graduate Program, University of California, San Diego, La Jolla, United States
| | - Christopher A Hinckley
- Gene Expression Laboratory, Howard Hughes Medical Institute, Salk Institute for Biological Studies, La Jolla, United States
| | - Niall J Moore
- Gene Expression Laboratory, Howard Hughes Medical Institute, Salk Institute for Biological Studies, La Jolla, United States
| | - Matthew T Pankratz
- Gene Expression Laboratory, Howard Hughes Medical Institute, Salk Institute for Biological Studies, La Jolla, United States
| | - Kathryn L Hilde
- Gene Expression Laboratory, Howard Hughes Medical Institute, Salk Institute for Biological Studies, La Jolla, United States.,Biomedical Sciences Graduate Program, University of California, San Diego, La Jolla, United States
| | - Shawn P Driscoll
- Gene Expression Laboratory, Howard Hughes Medical Institute, Salk Institute for Biological Studies, La Jolla, United States
| | - Marito Hayashi
- Gene Expression Laboratory, Howard Hughes Medical Institute, Salk Institute for Biological Studies, La Jolla, United States.,Biological Sciences Graduate Program, University of California, San Diego, La Jolla, United States
| | - Neal D Amin
- Gene Expression Laboratory, Howard Hughes Medical Institute, Salk Institute for Biological Studies, La Jolla, United States.,Biomedical Sciences Graduate Program, University of California, San Diego, La Jolla, United States.,Medical Scientist Training Program, University of California, San Diego, La Jolla, United States
| | - Dario Bonanomi
- Gene Expression Laboratory, Howard Hughes Medical Institute, Salk Institute for Biological Studies, La Jolla, United States
| | - Wesley D Gifford
- Gene Expression Laboratory, Howard Hughes Medical Institute, Salk Institute for Biological Studies, La Jolla, United States.,Medical Scientist Training Program, University of California, San Diego, La Jolla, United States.,Neurosciences Graduate Program, University of California, San Diego, La Jolla, United States
| | - Kamal Sharma
- Department of Anatomy and Cell Biology, University of Illinois at Chicago, Chicago, United States
| | - Martyn Goulding
- Molecular Neurobiology Laboratory, Salk Institute for Biological Studies, La Jolla, United States
| | - Samuel L Pfaff
- Gene Expression Laboratory, Howard Hughes Medical Institute, Salk Institute for Biological Studies, La Jolla, United States
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12
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Amin ND, Bai G, Klug JR, Bonanomi D, Pankratz MT, Gifford WD, Hinckley CA, Sternfeld MJ, Driscoll SP, Dominguez B, Lee KF, Jin X, Pfaff SL. Loss of motoneuron-specific microRNA-218 causes systemic neuromuscular failure. Science 2016; 350:1525-9. [PMID: 26680198 DOI: 10.1126/science.aad2509] [Citation(s) in RCA: 108] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Dysfunction of microRNA (miRNA) metabolism is thought to underlie diseases affecting motoneurons. One miRNA, miR-218, is abundantly and selectively expressed by developing and mature motoneurons. Here we show that mutant mice lacking miR-218 die neonatally and exhibit neuromuscular junction defects, motoneuron hyperexcitability, and progressive motoneuron cell loss, all of which are hallmarks of motoneuron diseases such as amyotrophic lateral sclerosis and spinal muscular atrophy. Gene profiling reveals that miR-218 modestly represses a cohort of hundreds of genes that are neuronally enriched but are not specific to a single neuron subpopulation. Thus, the set of messenger RNAs targeted by miR-218, designated TARGET(218), defines a neuronal gene network that is selectively tuned down in motoneurons to prevent neuromuscular failure and neurodegeneration.
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Affiliation(s)
- Neal D Amin
- Howard Hughes Medical Institute and Gene Expression Laboratory, Salk Institute for Biological Studies, 10010 North Torrey Pines Road, La Jolla, CA 92037, USA. Medical Scientist Training Program, University of California, San Diego (UCSD), 9500 Gilman Drive, La Jolla, CA 92037, USA. Biomedical Sciences Graduate Program, UCSD, 9500 Gilman Drive, La Jolla, CA 92037, USA
| | - Ge Bai
- Howard Hughes Medical Institute and Gene Expression Laboratory, Salk Institute for Biological Studies, 10010 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Jason R Klug
- Molecular Neurobiology Laboratory, Salk Institute for Biological Studies, 10010 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Dario Bonanomi
- Howard Hughes Medical Institute and Gene Expression Laboratory, Salk Institute for Biological Studies, 10010 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Matthew T Pankratz
- Howard Hughes Medical Institute and Gene Expression Laboratory, Salk Institute for Biological Studies, 10010 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Wesley D Gifford
- Howard Hughes Medical Institute and Gene Expression Laboratory, Salk Institute for Biological Studies, 10010 North Torrey Pines Road, La Jolla, CA 92037, USA. Medical Scientist Training Program, University of California, San Diego (UCSD), 9500 Gilman Drive, La Jolla, CA 92037, USA. Neurosciences Graduate Program, UCSD, 9500 Gilman Drive, La Jolla, CA 92037, USA
| | - Christopher A Hinckley
- Howard Hughes Medical Institute and Gene Expression Laboratory, Salk Institute for Biological Studies, 10010 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Matthew J Sternfeld
- Howard Hughes Medical Institute and Gene Expression Laboratory, Salk Institute for Biological Studies, 10010 North Torrey Pines Road, La Jolla, CA 92037, USA. Biological Sciences Graduate Program, UCSD, 9500 Gilman Drive, La Jolla, CA 92037, USA
| | - Shawn P Driscoll
- Howard Hughes Medical Institute and Gene Expression Laboratory, Salk Institute for Biological Studies, 10010 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Bertha Dominguez
- Peptide Biology Laboratory, Salk Institute for Biological Studies, 10010 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Kuo-Fen Lee
- Peptide Biology Laboratory, Salk Institute for Biological Studies, 10010 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Xin Jin
- Molecular Neurobiology Laboratory, Salk Institute for Biological Studies, 10010 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Samuel L Pfaff
- Howard Hughes Medical Institute and Gene Expression Laboratory, Salk Institute for Biological Studies, 10010 North Torrey Pines Road, La Jolla, CA 92037, USA.
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13
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Wang L, Mongera A, Bonanomi D, Cyganek L, Pfaff SL, Nüsslein-Volhard C, Marquardt T. A conserved axon type hierarchy governing peripheral nerve assembly. Development 2014; 141:1875-83. [DOI: 10.1242/dev.106211] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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14
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Bonanomi D, Chivatakarn O, Bai G, Abdesselem H, Lettieri K, Marquardt T, Pierchala BA, Pfaff SL. Ret is a multifunctional coreceptor that integrates diffusible- and contact-axon guidance signals. Cell 2012; 148:568-82. [PMID: 22304922 DOI: 10.1016/j.cell.2012.01.024] [Citation(s) in RCA: 94] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2011] [Revised: 12/14/2011] [Accepted: 01/17/2012] [Indexed: 02/02/2023]
Abstract
Growing axons encounter multiple guidance cues, but it is unclear how separate signals are resolved and integrated into coherent instructions for growth cone navigation. We report that glycosylphosphatidylinositol (GPI)-anchored ephrin-As function as "reverse" signaling receptors for motor axons when contacted by transmembrane EphAs present in the dorsal limb. Ephrin-A receptors are thought to depend on transmembrane coreceptors for transmitting signals intracellularly. We show that the receptor tyrosine kinase Ret is required for motor axon attraction mediated by ephrin-A reverse signaling. Ret also mediates GPI-anchored GFRα1 signaling in response to GDNF, a diffusible chemoattractant in the limb, indicating that Ret is a multifunctional coreceptor for guidance molecules. Axons respond synergistically to coactivation by GDNF and EphA ligands, and these cooperative interactions are gated by GFRα1 levels. Our studies uncover a hierarchical GPI-receptor signaling network that is constructed from combinatorial components and integrated through Ret using ligand coincidence detection.
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Affiliation(s)
- Dario Bonanomi
- Howard Hughes Medical Institute and Gene Expression Laboratory, The Salk Institute for Biological Studies, La Jolla, CA 92037, USA
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15
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Perlini LE, Botti F, Fornasiero EF, Giannandrea M, Bonanomi D, Amendola M, Naldini L, Benfenati F, Valtorta F. Effects of phosphorylation and neuronal activity on the control of synapse formation by synapsin I. J Cell Sci 2011; 124:3643-53. [DOI: 10.1242/jcs.086223] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Synapsins are synaptic vesicle (SV)-associated proteins that regulate synaptic transmission and neuronal differentiation. At early stages, Syn I and II phosphorylation at Ser9 by cAMP-dependent protein kinase (PKA) and Ca2+/calmodulin-dependent protein kinase I/IV modulates axon elongation and SV-precursor dynamics. We evaluated the requirement of Syn I for synapse formation by siRNA-mediated knockdown as well as by overexpression of either its wild-type (WT) form or its phosphorylation mutants. Syn1 knockdown at 14 days in vitro caused a decrease in the number of synapses, accompanied by a reduction of SV recycling. Although overexpression of WT Syn I was ineffective, overexpression of its phosphorylation mutants resulted in a complex temporal regulation of synapse density. At early stages of synaptogenesis, phosphomimetic Syn I S9E significantly increased the number of synapses. Conversely, dephosphomimetic Syn I S9A decreased synapse number at more advanced stages. Overexpression of either WT Syn I or its phosphomimetic S9E mutant rescued the decrease in synapse number caused by chronic treatment with tetrodotoxin at early stages, suggesting that Syn I participates in an alternative PKA-dependent mechanism that can compensate for the impairment of the activity-dependent synaptogenic pathway. Altogether these results indicate that Syn I is an important regulator of synapse formation, which adjusts synapse number in response to extracellular signals.
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Affiliation(s)
- Laura E. Perlini
- San Raffaele Scientific Institute and Vita-Salute University, Via Olgettina 58, 20132 Milano, Italy
- Department of Neuroscience and Brain Technologies, The Italian Institute of Technology, Via Morego 30, 16163 Genova, Italy
| | - Francesca Botti
- San Raffaele Scientific Institute and Vita-Salute University, Via Olgettina 58, 20132 Milano, Italy
| | - Eugenio F. Fornasiero
- San Raffaele Scientific Institute and Vita-Salute University, Via Olgettina 58, 20132 Milano, Italy
| | - Maila Giannandrea
- San Raffaele Scientific Institute and Vita-Salute University, Via Olgettina 58, 20132 Milano, Italy
| | - Dario Bonanomi
- San Raffaele Scientific Institute and Vita-Salute University, Via Olgettina 58, 20132 Milano, Italy
| | - Mario Amendola
- San Raffaele Scientific Institute and Vita-Salute University, Via Olgettina 58, 20132 Milano, Italy
- TIGET, Telethon Institute for Genetics and Medicine, Via Olgettina 58, 20132 Milano, Italy
| | - Luigi Naldini
- San Raffaele Scientific Institute and Vita-Salute University, Via Olgettina 58, 20132 Milano, Italy
- TIGET, Telethon Institute for Genetics and Medicine, Via Olgettina 58, 20132 Milano, Italy
| | - Fabio Benfenati
- Department of Neuroscience and Brain Technologies, The Italian Institute of Technology, Via Morego 30, 16163 Genova, Italy
- Department of Experimental Medicine, Section of Physiology, University of Genoa and National Institute of Neuroscience, Viale Benedetto XV, 3, 16132 Genova, Italy
| | - Flavia Valtorta
- San Raffaele Scientific Institute and Vita-Salute University, Via Olgettina 58, 20132 Milano, Italy
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16
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Bai G, Chivatakarn O, Bonanomi D, Lettieri K, Franco L, Xia C, Stein E, Ma L, Lewcock JW, Pfaff SL. Presenilin-dependent receptor processing is required for axon guidance. Cell 2011; 144:106-18. [PMID: 21215373 PMCID: PMC3034090 DOI: 10.1016/j.cell.2010.11.053] [Citation(s) in RCA: 95] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2010] [Revised: 09/20/2010] [Accepted: 11/08/2010] [Indexed: 01/17/2023]
Abstract
The Alzheimer's disease-linked gene presenilin is required for intramembrane proteolysis of amyloid-β precursor protein, contributing to the pathogenesis of neurodegeneration that is characterized by loss of neuronal connections, but the role of Presenilin in establishing neuronal connections is less clear. Through a forward genetic screen in mice for recessive genes affecting motor neurons, we identified the Columbus allele, which disrupts motor axon projections from the spinal cord. We mapped this mutation to the Presenilin-1 gene. Motor neurons and commissural interneurons in Columbus mutants lacking Presenilin-1 acquire an inappropriate attraction to Netrin produced by the floor plate because of an accumulation of DCC receptor fragments within the membrane that are insensitive to Slit/Robo silencing. Our findings reveal that Presenilin-dependent DCC receptor processing coordinates the interplay between Netrin/DCC and Slit/Robo signaling. Thus, Presenilin is a key neural circuit builder that gates the spatiotemporal pattern of guidance signaling, thereby ensuring neural projections occur with high fidelity.
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Affiliation(s)
- Ge Bai
- Howard Hughes Medical Institute and Gene Expression Laboratory, The Salk Institute for Biological Studies, 10010 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Onanong Chivatakarn
- Howard Hughes Medical Institute and Gene Expression Laboratory, The Salk Institute for Biological Studies, 10010 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Dario Bonanomi
- Howard Hughes Medical Institute and Gene Expression Laboratory, The Salk Institute for Biological Studies, 10010 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Karen Lettieri
- Howard Hughes Medical Institute and Gene Expression Laboratory, The Salk Institute for Biological Studies, 10010 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Laura Franco
- Howard Hughes Medical Institute and Gene Expression Laboratory, The Salk Institute for Biological Studies, 10010 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Caihong Xia
- Zilkha Neurogenetic Institute, Department of Cell and Neurobiology, Keck School of Medicine, University of Southern California, 1501 San Pablo Street, Los Angeles, CA 90089, USA
| | - Elke Stein
- Department of Molecular, Cellular, and Developmental Biology, Yale University, 266 Whitney Avenue, New Haven, CT 06520, USA
| | - Le Ma
- Zilkha Neurogenetic Institute, Department of Cell and Neurobiology, Keck School of Medicine, University of Southern California, 1501 San Pablo Street, Los Angeles, CA 90089, USA
| | - Joseph W. Lewcock
- Howard Hughes Medical Institute and Gene Expression Laboratory, The Salk Institute for Biological Studies, 10010 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Samuel L. Pfaff
- Howard Hughes Medical Institute and Gene Expression Laboratory, The Salk Institute for Biological Studies, 10010 North Torrey Pines Road, La Jolla, CA 92037, USA
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17
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Abstract
Motor neurons are functionally related, but represent a diverse collection of cells that show strict preferences for specific axon pathways during embryonic development. In this article, we describe the ligands and receptors that guide motor axons as they extend toward their peripheral muscle targets. Motor neurons share similar guidance molecules with many other neuronal types, thus one challenge in the field of axon guidance has been to understand how the vast complexity of brain connections can be established with a relatively small number of factors. In the context of motor guidance, we highlight some of the temporal and spatial mechanisms used to optimize the fidelity of pathfinding and increase the functional diversity of the signaling proteins.
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Affiliation(s)
- Dario Bonanomi
- Gene Expression Laboratory, The Salk Institute for Biological Studies, La Jolla, California 92037, USA
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Fornasiero EF, Bonanomi D, Benfenati F, Valtorta F. The role of synapsins in neuronal development. Cell Mol Life Sci 2009; 67:1383-96. [PMID: 20035364 DOI: 10.1007/s00018-009-0227-8] [Citation(s) in RCA: 85] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2009] [Revised: 11/22/2009] [Accepted: 12/04/2009] [Indexed: 12/23/2022]
Abstract
The synapsins, the first identified synaptic vesicle-specific proteins, are phosphorylated on multiple sites by a number of protein kinases and are involved in neurite outgrowth and synapse formation as well as in synaptic transmission. In mammals, the synapsin family consists of at least 10 isoforms encoded by 3 distinct genes and composed by a mosaic of conserved and variable domains. The synapsins are highly conserved evolutionarily, and orthologues have been found in invertebrates and lower vertebrates. Within nerve terminals, synapsins are implicated in multiple interactions with presynaptic proteins and the actin cytoskeleton. Via these interactions, synapsins control several mechanisms important for neuronal homeostasis. In this review, we describe the main functional features of the synapsins, in relation to the complex role played by these phosphoproteins in neuronal development.
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Affiliation(s)
- Eugenio F Fornasiero
- San Raffaele Scientific Institute, Vita-Salute University, Via Olgettina 58, 20132, Milan, Italy
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Bonanomi D, Fornasiero EF, Valdez G, Halegoua S, Benfenati F, Menegon A, Valtorta F. Identification of a developmentally regulated pathway of membrane retrieval in neuronal growth cones. J Cell Sci 2008; 121:3757-69. [PMID: 18940911 DOI: 10.1242/jcs.033803] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
The growth-cone plasma membrane constantly reconfigures during axon navigation and upon target recognition. The identity and regulation of the membrane pathway(s) participating in remodeling of the growth-cone surface remain elusive. Here, we identify a constitutive, high-capacity plasma-membrane-recycling activity in the axonal growth cones, which is mediated by a novel bulk endocytic pathway that is mechanistically related to macropinocytosis. This pathway generates large compartments at sites of intense actin-based membrane ruffling through the actions of phosphatidylinositol 3-kinase, the small GTPase Rac1 and the pinocytic chaperone Pincher. At early developmental stages, bulk endocytosis is the primary endocytic pathway for rapid retrieval of the growth-cone plasma membrane. At later stages, during the onset of synaptogenesis, an intrinsic program of maturation leads to downregulation of basal bulk endocytosis and the emergence of depolarization-induced synaptic-vesicle exo-endocytosis. We propose that the control of bulk membrane retrieval contributes to the homeostatic regulation of the axonal plasma membrane and to growth-cone remodeling during axonal outgrowth. In addition, we suggest that the downregulation of bulk endocytosis during synaptogenesis might contribute to the preservation of synaptic-vesicle specificity.
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Affiliation(s)
- Dario Bonanomi
- S. Raffaele Scientific Institute/Vita-Salute University and IIT Unit of Molecular Neuroscience, 20132 Milano, Italy
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Gallarda BW, Bonanomi D, Müller D, Brown A, Alaynick WA, Andrews SE, Lemke G, Pfaff SL, Marquardt T. Segregation of axial motor and sensory pathways via heterotypic trans-axonal signaling. Science 2008; 320:233-6. [PMID: 18403711 DOI: 10.1126/science.1153758] [Citation(s) in RCA: 80] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Execution of motor behaviors relies on circuitries effectively integrating immediate sensory feedback to efferent pathways controlling muscle activity. It remains unclear how, during neuromuscular circuit assembly, sensory and motor projections become incorporated into tightly coordinated, yet functionally separate pathways. We report that, within axial nerves, establishment of discrete afferent and efferent pathways depends on coordinate signaling between coextending sensory and motor projections. These heterotypic axon-axon interactions require motor axonal EphA3/EphA4 receptor tyrosine kinases activated by cognate sensory axonal ephrin-A ligands. Genetic elimination of trans-axonal ephrin-A --> EphA signaling in mice triggers drastic motor-sensory miswiring, culminating in functional efferents within proximal afferent pathways. Effective assembly of a key circuit underlying motor behaviors thus critically depends on trans-axonal signaling interactions resolving motor and sensory projections into discrete pathways.
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Affiliation(s)
- Benjamin W Gallarda
- Gene Expression Laboratory, Salk Institute for Biological Studies, 10010 North Torrey Pines Road, La Jolla, CA 92037, USA
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Badaloni A, Bonanomi D, Albieri I, Givogri I, Bongarzone E, Valtorta F, Consalez GG. Transgenic mice expressing a dual, CRE-inducible reporter for the analysis of axon guidance and synaptogenesis. Genesis 2007; 45:405-12. [PMID: 17554764 DOI: 10.1002/dvg.20307] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Improved and modular tools are needed for the neuroanatomical dissection of CNS axonal tracts, and to study the cell-intrinsic and cell-extrinsic cues that govern their assembly and plasticity. Here we describe a general purpose transgenic tracer that can be used to visualize axonal tracts and synaptic terminals in any region of the embryonic neural tube or postnatal CNS, on any wild type or mutant genetic background. The construct permits CRE-inducible expression of a dicistronic axonal marker encoding two surface reporter proteins: a farnesylated GFP and the human Placental Alkaline Phosphatase (PLAP). Both proteins localize alongside the neuronal surface, permitting the concomitant detection of cell body, neurites, and presynaptic and postsynaptic sites in the same neuron. This provides a CRE-inducible dual system for imaging neural circuits in vivo, and to study their assembly and remodeling in cultured neurons, neural stem cells, and tissue explants derived from the reporter line. Unlike existing lines, this reporter does not encode a ubiquitously expressed, floxable LacZ gene, permitting the simultaneous analysis of beta galactosidase activity in mutant lines.
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Affiliation(s)
- Aurora Badaloni
- San Raffaele Scientific Institute and Università Vita-Salute San Raffaele, Milano, Italy
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22
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Abstract
Biogenesis and recycling of synaptic vesicles are accompanied by sorting processes that preserve the molecular composition of the compartments involved. In the present study, we have addressed the targeting of synaptobrevin 2/VAMP2 (vesicle-associated membrane protein 2), a critical component of the synaptic vesicle--fusion machinery, in a heterotypic context where its sorting is not confounded by the presence of other neuron-specific molecules. Ectopically expressed synaptophysin I interacts with VAMP2 and alters its default surface targeting to a prominent vesicular distribution, with no effect on the targeting of other membrane proteins. Protein-protein interaction is not sufficient for the control of VAMP2 sorting, which is mediated by the C-terminal domain of synaptophysin I. Synaptophysin I directs the sorting of VAMP2 to vesicles before surface delivery, without influencing VAMP2 endocytosis. Consistent with this, dynamin and alpha-SNAP (soluble N-ethylmaleimide-sensitive fusion protein-attachment protein) mutants which block trafficking at the plasma membrane do not abrogate the effect of synaptophysin I on VAMP2 sorting. These results indicate that the sorting determinants of synaptic vesicle proteins can operate independently of a neuronal context and implicate the association of VAMP2 with synaptophysin I in the specification of the pathway of synaptic vesicle biogenesis.
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Affiliation(s)
- Dario Bonanomi
- *San Raffaele Scientific Institute and “Vita-Salute” University, Via Olgettina 58, 20132 Milan, Italy
| | - Laura Rusconi
- *San Raffaele Scientific Institute and “Vita-Salute” University, Via Olgettina 58, 20132 Milan, Italy
| | - Chiara Agnese Colombo
- *San Raffaele Scientific Institute and “Vita-Salute” University, Via Olgettina 58, 20132 Milan, Italy
| | - Fabio Benfenati
- †Department of Neuroscience, The Italian Institute of Technology, Genova, Italy
- ‡Department of Experimental Medicine, University of Genova, Via Benedetto XV 3, 16132 Genova, Italy
| | - Flavia Valtorta
- *San Raffaele Scientific Institute and “Vita-Salute” University, Via Olgettina 58, 20132 Milan, Italy
- §The Italian Institute of Technology, Research Unit of Molecular Neuroscience, via Olgettina 58, 20132 Milan, Italy
- To whom correspondence should be addressed (email )
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Bonanomi D, Menegon A, Baldelli P, Benfenati F, Valtorta F. [P60]: Protein kinase a‐mediated synapsin I phosphorylation is a developmentally conserved mechanism for the control of synaptic vesicle dynamics. Int J Dev Neurosci 2006. [DOI: 10.1016/j.ijdevneu.2006.09.123] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Affiliation(s)
- D. Bonanomi
- San Raffaele Scientific Institute and “Vita‐Salute” UniversityItaly
| | - A. Menegon
- San Raffaele Scientific Institute and “Vita‐Salute” UniversityItaly
| | | | | | - F. Valtorta
- San Raffaele Scientific Institute and “Vita‐Salute” UniversityItaly
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Menegon A, Bonanomi D, Albertinazzi C, Lotti F, Ferrari G, Kao HT, Benfenati F, Baldelli P, Valtorta F. Protein kinase A-mediated synapsin I phosphorylation is a central modulator of Ca2+-dependent synaptic activity. J Neurosci 2006; 26:11670-81. [PMID: 17093089 PMCID: PMC6674776 DOI: 10.1523/jneurosci.3321-06.2006] [Citation(s) in RCA: 111] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Protein kinase A (PKA) modulates several steps of synaptic transmission. However, the identification of the mediators of these effects is as yet incomplete. Synapsins are synaptic vesicle (SV)-associated phosphoproteins that represent the major presynaptic targets of PKA. We show that, in hippocampal neurons, cAMP-dependent pathways affect SV exocytosis and that this effect is primarily brought about through synapsin I phosphorylation. Phosphorylation by PKA, by promoting dissociation of synapsin I from SVs, enhances the rate of SV exocytosis on stimulation. This effect becomes relevant when neurons are challenged with sustained stimulation, because it appears to counteract synaptic depression and accelerate recovery from depression by fostering the supply of SVs from the reserve pool to the readily releasable pool. In contrast, synapsin phosphorylation appears to be dispensable for the effects of cAMP on the frequency and amplitude of spontaneous synaptic currents and on the amplitude of evoked synaptic currents. The modulation of depolarization-evoked SV exocytosis by PKA phosphorylation of synapsin I is primarily caused by calmodulin (CaM)-dependent activation of cAMP pathways rather than by direct activation of CaM kinases. These data define a hierarchical crosstalk between cAMP- and CaM-dependent cascades and point to synapsin as a major effector of PKA in the modulation of activity-dependent SV exocytosis.
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Affiliation(s)
- Andrea Menegon
- San Raffaele Scientific Institute and “Vita-Salute” University, 20132 Milan, Italy
| | - Dario Bonanomi
- San Raffaele Scientific Institute and “Vita-Salute” University, 20132 Milan, Italy
| | - Chiara Albertinazzi
- San Raffaele Scientific Institute and “Vita-Salute” University, 20132 Milan, Italy
| | - Francesco Lotti
- San Raffaele Scientific Institute and “Vita-Salute” University, 20132 Milan, Italy
- Telethon Institute for Gene Therapy, 20132 Milan, Italy
| | - Giuliana Ferrari
- San Raffaele Scientific Institute and “Vita-Salute” University, 20132 Milan, Italy
- Telethon Institute for Gene Therapy, 20132 Milan, Italy
| | - Hung-Teh Kao
- Nathan Kline Institute for Psychiatric Research, Orangeburg, New York 12229
| | - Fabio Benfenati
- Department of Neuroscience, The Italian Institute of Technology Central Laboratories and Department of Experimental Medicine, Section of Physiology, University of Genova, 16126 Genova, Italy, and
| | - Pietro Baldelli
- Department of Neuroscience, The Italian Institute of Technology Central Laboratories and Department of Experimental Medicine, Section of Physiology, University of Genova, 16126 Genova, Italy, and
| | - Flavia Valtorta
- San Raffaele Scientific Institute and “Vita-Salute” University, 20132 Milan, Italy
- The Italian Institute of Technology, Research Unit of Molecular Neuroscience, 20132 Milan, Italy
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Bonanomi D, Benfenati F, Valtorta F. Protein sorting in the synaptic vesicle life cycle. Prog Neurobiol 2006; 80:177-217. [PMID: 17074429 DOI: 10.1016/j.pneurobio.2006.09.002] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2006] [Revised: 09/14/2006] [Accepted: 09/18/2006] [Indexed: 01/06/2023]
Abstract
At early stages of differentiation neurons already contain many of the components necessary for synaptic transmission. However, in order to establish fully functional synapses, both the pre- and postsynaptic partners must undergo a process of maturation. At the presynaptic level, synaptic vesicles (SVs) must acquire the highly specialized complement of proteins, which make them competent for efficient neurotransmitter release. Although several of these proteins have been characterized and linked to precise functions in the regulation of the SV life cycle, a systematic and unifying view of the mechanisms underlying selective protein sorting during SV biogenesis remains elusive. Since SV components do not share common sorting motifs, their targeting to SVs likely relies on a complex network of protein-protein and protein-lipid interactions, as well as on post-translational modifications. Pleiomorphic carriers containing SV proteins travel and recycle along the axon in developing neurons. Nevertheless, SV components appear to eventually undertake separate trafficking routes including recycling through the neuronal endomembrane system and the plasmalemma. Importantly, SV biogenesis does not appear to be limited to a precise stage during neuronal differentiation, but it rather continues throughout the entire neuronal lifespan and within synapses. At nerve terminals, remodeling of the SV membrane results from the use of alternative exocytotic pathways and possible passage through as yet poorly characterized vacuolar/endosomal compartments. As a result of both processes, SVs with heterogeneous molecular make-up, and hence displaying variable competence for exocytosis, may be generated and coexist within the same nerve terminal.
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Affiliation(s)
- Dario Bonanomi
- Department of Neuroscience, San Raffaele Scientific Institute and Vita-Salute University, Milan, Italy
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Bonanomi D, Menegon A, Miccio A, Ferrari G, Corradi A, Kao HT, Benfenati F, Valtorta F. Phosphorylation of synapsin I by cAMP-dependent protein kinase controls synaptic vesicle dynamics in developing neurons. J Neurosci 2006; 25:7299-308. [PMID: 16093379 PMCID: PMC6725302 DOI: 10.1523/jneurosci.1573-05.2005] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
In developing neurons, synaptic vesicles (SVs) undergo cycles of exo-endocytosis along isolated axons. However, it is currently unknown whether SV exocytosis is regulated before synaptogenesis. Here, we show that cAMP-dependent pathways affect SV distribution and recycling in the axonal growth cone and that these effects are mediated by the SV-associated phosphoprotein synapsin I. The presence of synapsin I on SVs is necessary for the correct localization of the vesicles in the central portion of the growth cone. Phosphorylation of synapsin I by cAMP-dependent protein kinase (protein kinase A) causes the dissociation of the protein from the SV membrane, allowing diffusion of the vesicles to the periphery of the growth cone and enhancing their rate of recycling. These results provide new clues as to the bases of the well known activity of synapsin I in synapse maturation and indicate that molecular mechanisms similar to those operating at mature nerve terminals are active in developing neurons to regulate the SV life cycle before synaptogenesis.
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Affiliation(s)
- Dario Bonanomi
- Department of Neuroscience, San Raffaele Scientific Institute, Vita-Salute University, 20132 Milan, Italy
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Bellomunno C, Bonanomi D, Falciola L, Longhi M, Mussini P, Doubova L, Di Silvestro G. Building up an electrocatalytic activity scale of cathode materials for organic halide reductions. Electrochim Acta 2005. [DOI: 10.1016/j.electacta.2004.10.047] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Bonanomi D, Pennuto M, Rigoni M, Rossetto O, Montecucco C, Valtorta F. Taipoxin Induces Synaptic Vesicle Exocytosis and Disrupts the Interaction of Synaptophysin I with VAMP2. Mol Pharmacol 2005; 67:1901-8. [PMID: 15695624 DOI: 10.1124/mol.104.005678] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The application of the snake neurotoxin taipoxin to hippocampal neurons in culture induced Ca(2+)-dependent synaptic vesicle (SV) exocytosis, with swelling of nerve terminals and redistribution of SV proteins to the axolemma. Using digital imaging videomicroscopy to measure fluorescence resonance energy transfer in live neurons, we also found that taipoxin modulates the machinery for neurosecretion by causing dissociation of the SV proteins synaptobrevin 2 and synaptophysin I at a stage preceding taipoxin-induced facilitation of SV fusion. These early effects of the toxin are followed by severe impairment of SV exo-endocytosis, which might underlie the prevention of neurotransmitter release reported after intoxication by taipoxin.
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Affiliation(s)
- Dario Bonanomi
- Department of Neuroscience, San Raffaele Scientific Institute, via Olgettina 58, 20132 Milan, Italy
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Abstract
Synaptophysin (Syp) was the first synaptic vesicle (SV) protein to be cloned. Since its discovery in 1985, it has been used by us and by many laboratories around the world as an invaluable marker to study the distribution of synapses in the brain and to uncover the basic features of the life cycle of SVs. Although single gene ablation of Syp does not lead to an overt phenotype, a large body of experimental data both in vitro and in vivo indicate that Syp (alone or in association with homologous proteins) is involved in multiple, important aspects of SV exo-endocytosis, including regulation of SNARE assembly into the fusion core complex, formation of the fusion pore initiating neurotransmitter release, activation of SV endocytosis and SV biogenesis. In this article, we summarise the main results of the studies on Syp carried out by our and other laboratories, and explain why we believe that Syp plays a major role in SV trafficking.
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Affiliation(s)
- Flavia Valtorta
- Department of Neuroscience, S. Raffaele Scientific Institute and Vita-Salute University, Milan, Italy.
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Abstract
Synaptic vesicle (SV) proteins are synthesized at the level of the cell body and transported down the axon in membrane precursors of SVs. To investigate the mechanisms underlying sorting of proteins to SVs, fluorescent chimeras of vesicle-associated membrane protein (VAMP) 2, its highly homologous isoform VAMP1 and synaptotagmin I (SytI) were expressed in hippocampal neurons in culture. Interestingly, the proteins displayed a diffuse component of distribution along the axon. In addition, VAMP2 was found to travel in vesicles that constitutively fuse with the plasma membrane. Coexpression of VAMP2 with synaptophysin I (SypI), a major resident of SVs, restored the correct sorting of VAMP2 to SVs. The effect of SypI on VAMP2 sorting was dose dependent, being reversed by increasing VAMP2 expression levels, and highly specific, because the sorting of the SV proteins VAMP1 and SytI was not affected by SypI. The cytoplasmic domain of VAMP2 was found to be necessary for both the formation of VAMP2-SypI hetero-dimers and for VAMP2 sorting to SVs. These data support a role for SypI in directing the correct sorting of VAMP2 in neurons and demonstrate that a direct interaction between the two proteins is required for SypI in order to exert its effect.
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Affiliation(s)
- Maria Pennuto
- Department of Neuroscience, San Raffaele Scientific Institute and Vita-Salute University, 20132 Milano, Italy
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Contestabile A, Bonanomi D, Burgaya F, Girault JA, Valtorta F. Localization of focal adhesion kinase isoforms in cells of the central nervous system. Int J Dev Neurosci 2003; 21:83-93. [PMID: 12615084 DOI: 10.1016/s0736-5748(02)00126-0] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Focal adhesion kinase (FAK) is a non-receptor tyrosine kinase which in non-neuronal cells is localized to focal adhesions, where it participates to adhesion-dependent intracellular signalling. FAK is highly expressed in the central nervous system both during development and in the adult. FAK(+), a splice isoform of FAK selectively enriched in neurons, contains a three-amino acid insertion in the carboxy-terminal sequence responsible for the localization of FAK to focal adhesions. Enhanced green fluorescent protein-tagged constructs were used to study the targeting of FAK and FAK(+) in neuronal and non-neuronal cells of the central nervous system. In transfected non-neuronal cells, both fusion proteins colocalized with vinculin in focal contacts. When expressed in hippocampal neurons in culture, both chimeras were locally concentrated in the growth cone, where they overlapped with F-actin enrichments but not with vinculin. In the growth cone of living neurons, the FAK(+) chimera showed a dynamic relocalization to membrane ruffles and to the tips of the membrane protrusions induced by cytochalasin D treatment, indicating a dependence of FAK distribution on F-actin organization. Since virtually identical patterns of distribution were found for FAK and FAK(+) chimeras, it follows that the additional insertion in FAK(+) is not responsible for the localization of the kinase. Finally, we showed that the carboxy-terminal domain of both FAK and FAK(+) is sufficient to mediate the localization of the proteins to focal adhesions in non-neuronal cells and to maintain their correct intracellular targeting in neurons.
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Affiliation(s)
- Andrea Contestabile
- Department of Neuroscience, S. Raffaele Scientific Institute and Vita-Salute University, Milano, Italy
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