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Mercaldo V, Vidimova B, Gastaldo D, Fernández E, Lo AC, Cencelli G, Pedini G, De Rubeis S, Longo F, Klann E, Smit AB, Grant SGN, Achsel T, Bagni C. Altered striatal actin dynamics drives behavioral inflexibility in a mouse model of fragile X syndrome. Neuron 2023; 111:1760-1775.e8. [PMID: 36996810 DOI: 10.1016/j.neuron.2023.03.008] [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] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2022] [Revised: 12/21/2022] [Accepted: 03/06/2023] [Indexed: 03/31/2023]
Abstract
The proteome of glutamatergic synapses is diverse across the mammalian brain and involved in neurodevelopmental disorders (NDDs). Among those is fragile X syndrome (FXS), an NDD caused by the absence of the functional RNA-binding protein FMRP. Here, we demonstrate how the brain region-specific composition of postsynaptic density (PSD) contributes to FXS. In the striatum, the FXS mouse model shows an altered association of the PSD with the actin cytoskeleton, reflecting immature dendritic spine morphology and reduced synaptic actin dynamics. Enhancing actin turnover with constitutively active RAC1 ameliorates these deficits. At the behavioral level, the FXS model displays striatal-driven inflexibility, a typical feature of FXS individuals, which is rescued by exogenous RAC1. Striatal ablation of Fmr1 is sufficient to recapitulate behavioral impairments observed in the FXS model. These results indicate that dysregulation of synaptic actin dynamics in the striatum, a region largely unexplored in FXS, contributes to the manifestation of FXS behavioral phenotypes.
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Affiliation(s)
- Valentina Mercaldo
- Department of Fundamental Neurosciences, Université de Lausanne, 1005 Lausanne, Switzerland
| | - Barbora Vidimova
- Department of Fundamental Neurosciences, Université de Lausanne, 1005 Lausanne, Switzerland
| | - Denise Gastaldo
- Department of Fundamental Neurosciences, Université de Lausanne, 1005 Lausanne, Switzerland
| | - Esperanza Fernández
- VIB & UGent Center for Medical Biotechnology, Universiteit Gent, 9052 Ghent, Belgium
| | - Adrian C Lo
- Department of Fundamental Neurosciences, Université de Lausanne, 1005 Lausanne, Switzerland
| | - Giulia Cencelli
- Department of Biomedicine and Prevention, Università degli Studi di Roma "Tor Vergata", 00133 Rome, Italy; Institute of Neurosurgery, Fondazione Policlinico Universitario A. Gemelli IRCCS - Università Cattolica del Sacro Cuore, 00168 Rome, Italy
| | - Giorgia Pedini
- Department of Biomedicine and Prevention, Università degli Studi di Roma "Tor Vergata", 00133 Rome, Italy
| | - Silvia De Rubeis
- Seaver Autism Center for Research and Treatment, Department of Psychiatry, Friedman Brain Institute, Mindich Child Health and Development Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Francesco Longo
- Center for Neural Science, New York University, New York, NY 10029, USA
| | - Eric Klann
- Center for Neural Science, New York University, New York, NY 10029, USA
| | - August B Smit
- Center for Neurogenomics and Cognitive Research, Vrije Universiteit Amsterdam, 1081 HV Amsterdam, The Netherlands
| | - Seth G N Grant
- Center for the Clinical Brain Sciences and Simons Initiatives for the Developing Brain, The University of Edinburgh, Edinburgh EH16 4SB, Scotland
| | - Tilmann Achsel
- Department of Fundamental Neurosciences, Université de Lausanne, 1005 Lausanne, Switzerland.
| | - Claudia Bagni
- Department of Fundamental Neurosciences, Université de Lausanne, 1005 Lausanne, Switzerland; Department of Biomedicine and Prevention, Università degli Studi di Roma "Tor Vergata", 00133 Rome, Italy.
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