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Jaudon F, Cingolani LA. Unlocking mechanosensitivity: integrins in neural adaptation. Trends Cell Biol 2024:S0962-8924(24)00046-1. [PMID: 38514304 DOI: 10.1016/j.tcb.2024.02.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2024] [Revised: 02/22/2024] [Accepted: 02/27/2024] [Indexed: 03/23/2024]
Abstract
Mechanosensitivity extends beyond sensory cells to encompass most neurons in the brain. Here, we explore recent research on the role of integrins, a diverse family of adhesion molecules, as crucial biomechanical sensors translating mechanical forces into biochemical and electrical signals in the brain. The varied biomechanical properties of neuronal integrins, including their force-dependent conformational states and ligand interactions, dictate their specific functions. We discuss new findings on how integrins regulate filopodia and dendritic spines, shedding light on their contributions to synaptic plasticity, and explore recent discoveries on how they engage with metabotropic receptors and ion channels, highlighting their direct participation in electromechanical transduction. Finally, to facilitate a deeper understanding of these developments, we present molecular and biophysical models of mechanotransduction.
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Affiliation(s)
- Fanny Jaudon
- Department of Life Sciences, University of Trieste, 34127 Trieste, Italy; IRCCS Ospedale Policlinico San Martino, 16132 Genoa, Italy
| | - Lorenzo A Cingolani
- Department of Life Sciences, University of Trieste, 34127 Trieste, Italy; Center for Synaptic Neuroscience and Technology (NSYN), Fondazione Istituto Italiano di Tecnologia (IIT), 16132 Genoa, Italy.
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Handwerk CJ, Denzler CJ, Kalinowski AR, Cook HN, Rodriguez HV, Bland KM, Brett CA, Swinehart BD, Vinson EC, Vidal GS. Integrin β3 regulates apical dendritic morphology of pyramidal neurons throughout hippocampal CA3. Hippocampus 2023; 33:936-947. [PMID: 36967540 PMCID: PMC10952146 DOI: 10.1002/hipo.23530] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2022] [Revised: 03/09/2023] [Accepted: 03/13/2023] [Indexed: 03/29/2023]
Abstract
In excitatory hippocampal pyramidal neurons, integrin β3 is critical for synaptic maturation and plasticity in vitro. Itgb3 is a potential autism susceptibility gene that regulates dendritic morphology in the cerebral cortex in a cell-specific manner. However, it is unknown what role Itgb3 could have in regulating hippocampal pyramidal dendritic morphology in vivo, a key feature that is aberrant in many forms of autism and intellectual disability. We found that Itgb3 mRNA is expressed in the stratum pyramidale of CA3. We examined the apical dendritic morphology of CA3 hippocampal pyramidal neurons in conditional Itgb3 knockouts and controls, utilizing the Thy1-GFP-M line. We fully reconstructed the apical dendrite of each neuron and determined each neuron's precise location along the dorsoventral, proximodistal, and radial axes of the stratum pyramidale. We found a very strong effect for Itgb3 expression on CA3 apical dendritic morphology: neurons from conditional Itgb3 knockouts had longer and thinner apical dendrites than controls, particularly in higher branch orders. We also assessed potential relationships between pairs of topographic or morphological variables, finding that most variable pairs were free from any linear relationships to each other. We also found that some neurons from controls, but not conditional Itgb3 knockouts, had a graded pattern of overall diameter along the dorsoventral and proximodistal axes of the stratum pyramidale of CA3. Taken together, Itgb3 is essential for constructing normal dendritic morphology in pyramidal neurons throughout CA3.
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Affiliation(s)
| | - Collin J. Denzler
- Department of BiologyJames Madison UniversityMSC 7801, HarrisonburgVirginia22807USA
| | - Anna R. Kalinowski
- Department of BiologyJames Madison UniversityMSC 7801, HarrisonburgVirginia22807USA
| | - Hollyn N. Cook
- Department of BiologyJames Madison UniversityMSC 7801, HarrisonburgVirginia22807USA
| | - Hilda V. Rodriguez
- Department of BiologyJames Madison UniversityMSC 7801, HarrisonburgVirginia22807USA
| | - Katherine M. Bland
- Department of BiologyJames Madison UniversityMSC 7801, HarrisonburgVirginia22807USA
| | - Cooper A. Brett
- Department of BiologyJames Madison UniversityMSC 7801, HarrisonburgVirginia22807USA
| | - Brian D. Swinehart
- Department of BiologyJames Madison UniversityMSC 7801, HarrisonburgVirginia22807USA
| | - Elizabeth C. Vinson
- Department of BiologyJames Madison UniversityMSC 7801, HarrisonburgVirginia22807USA
| | - George S. Vidal
- Department of BiologyJames Madison UniversityMSC 7801, HarrisonburgVirginia22807USA
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Celora L, Jaudon F, Vitale C, Cingolani LA. Regulation of dendritic spine length in corticopontine layer V pyramidal neurons by autism risk gene β3 integrin. Mol Brain 2023; 16:49. [PMID: 37296444 DOI: 10.1186/s13041-023-01031-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2023] [Accepted: 04/27/2023] [Indexed: 06/12/2023] Open
Abstract
The relationship between autism spectrum disorder (ASD) and dendritic spine abnormalities is well known, but it is unclear whether the deficits relate to specific neuron types and brain regions most relevant to ASD. Recent genetic studies have identified a convergence of ASD risk genes in deep layer pyramidal neurons of the prefrontal cortex. Here, we use retrograde recombinant adeno-associated viruses to label specifically two major layer V pyramidal neuron types of the medial prefrontal cortex: the commissural neurons, which put the two cerebral hemispheres in direct communication, and the corticopontine neurons, which transmit information outside the cortex. We compare the basal dendritic spines on commissural and corticopontine neurons in WT and KO mice for the ASD risk gene Itgb3, which encodes for the cell adhesion molecule β3 integrin selectively enriched in layer V pyramidal neurons. Regardless of the genotype, corticopontine neurons had a higher ratio of stubby to mushroom spines than commissural neurons. β3 integrin affected selectively spine length in corticopontine neurons. Ablation of β3 integrin resulted in corticopontine neurons lacking long (> 2 μm) thin dendritic spines. These findings suggest that a deficiency in β3 integrin expression compromises specifically immature spines on corticopontine neurons, thereby reducing the cortical territory they can sample. Because corticopontine neurons receive extensive local and long-range excitatory inputs before relaying information outside the cortex, specific alterations in dendritic spines of corticopontine neurons may compromise the computational output of the full cortex, thereby contributing to ASD pathophysiology.
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Affiliation(s)
- Lucia Celora
- Department of Life Sciences, University of Trieste, Trieste, 34127, Italy
| | - Fanny Jaudon
- Department of Life Sciences, University of Trieste, Trieste, 34127, Italy
- IRCCS Ospedale Policlinico San Martino, Genoa, 16132, Italy
| | - Carmela Vitale
- Center for Synaptic Neuroscience and Technology (NSYN), Fondazione Istituto Italiano di Tecnologia (IIT), Genoa, 16132, Italy
| | - Lorenzo A Cingolani
- Department of Life Sciences, University of Trieste, Trieste, 34127, Italy.
- Center for Synaptic Neuroscience and Technology (NSYN), Fondazione Istituto Italiano di Tecnologia (IIT), Genoa, 16132, Italy.
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Moretto E, Miozzo F, Longatti A, Bonnet C, Coussen F, Jaudon F, Cingolani LA, Passafaro M. The tetraspanin TSPAN5 regulates AMPAR exocytosis by interacting with the AP4 complex. eLife 2023; 12:76425. [PMID: 36795458 PMCID: PMC9934860 DOI: 10.7554/elife.76425] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2021] [Accepted: 01/25/2023] [Indexed: 02/17/2023] Open
Abstract
Intracellular trafficking of AMPA receptors is a tightly regulated process which involves several adaptor proteins, and is crucial for the activity of excitatory synapses both in basal conditions and during synaptic plasticity. We found that, in rat hippocampal neurons, an intracellular pool of the tetraspanin TSPAN5 promotes exocytosis of AMPA receptors without affecting their internalisation. TSPAN5 mediates this function by interacting with the adaptor protein complex AP4 and Stargazin and possibly using recycling endosomes as a delivery route. This work highlights TSPAN5 as a new adaptor regulating AMPA receptor trafficking.
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Affiliation(s)
- Edoardo Moretto
- Institute of Neuroscience, CNRVedano al LambroItaly,NeuroMI Milan Center for Neuroscience, University of Milano-BicoccaMilanItaly
| | | | | | - Caroline Bonnet
- University of Bordeaux, Interdisciplinary Institute for NeuroscienceBordeauxFrance
| | - Francoise Coussen
- University of Bordeaux, Interdisciplinary Institute for NeuroscienceBordeauxFrance
| | - Fanny Jaudon
- Department of Life Sciences, University of TriesteTriesteItaly,IRCCS Ospedale Policlinico San MartinoGenoaItaly
| | - Lorenzo A Cingolani
- Department of Life Sciences, University of TriesteTriesteItaly,Center for Synaptic Neuroscience and Technology (NSYN), Istituto Italiano di Tecnologia (IIT)GenoaItaly
| | - Maria Passafaro
- Institute of Neuroscience, CNRVedano al LambroItaly,NeuroMI Milan Center for Neuroscience, University of Milano-BicoccaMilanItaly
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Jaudon F, Thalhammer A, Zentilin L, Cingolani LA. CRISPR-mediated activation of autism gene Itgb3 restores cortical network excitability via mGluR5 signaling. MOLECULAR THERAPY - NUCLEIC ACIDS 2022; 29:462-480. [PMID: 36035754 PMCID: PMC9382421 DOI: 10.1016/j.omtn.2022.07.013] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/28/2021] [Accepted: 07/15/2022] [Indexed: 01/12/2023]
Abstract
Many mutations in autism spectrum disorder (ASD) affect a single allele, indicating a key role for gene dosage in ASD susceptibility. Recently, haplo-insufficiency of ITGB3, the gene encoding the extracellular matrix receptor β3 integrin, was associated with ASD. Accordingly, Itgb3 knockout (KO) mice exhibit autism-like phenotypes. The pathophysiological mechanisms of Itgb3 remain, however, unknown, and the potential of targeting this gene for developing ASD therapies uninvestigated. By combining molecular, biochemical, imaging, and pharmacological analyses, we establish that Itgb3 haplo-insufficiency impairs cortical network excitability by promoting extra-synaptic over synaptic signaling of the metabotropic glutamate receptor mGluR5, which is similarly dysregulated in fragile X syndrome, the most frequent monogenic form of ASD. To assess the therapeutic potential of regulating Itgb3 gene dosage, we implemented CRISPR activation and compared its efficacy with that of a pharmacological rescue strategy for fragile X syndrome. Correction of neuronal Itgb3 haplo-insufficiency by CRISPR activation rebalanced network excitability as effectively as blockade of mGluR5 with the selective antagonist MPEP. Our findings reveal an unexpected functional interaction between two ASD genes, thereby validating the pathogenicity of ITGB3 haplo-insufficiency. Further, they pave the way for exploiting CRISPR activation as gene therapy for normalizing gene dosage and network excitability in ASD.
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Affiliation(s)
- Fanny Jaudon
- Center for Synaptic Neuroscience and Technology (NSYN), Fondazione Istituto Italiano di Tecnologia (IIT), 16132 Genoa, Italy
- Department of Life Sciences, University of Trieste, 34127 Trieste, Italy
| | - Agnes Thalhammer
- Department of Life Sciences, University of Trieste, 34127 Trieste, Italy
- IRCCS Ospedale Policlinico San Martino, 16132 Genoa, Italy
| | - Lorena Zentilin
- AAV Vector Unit, International Centre for Genetic Engineering and Biotechnology (ICGEB), 34149 Trieste, Italy
| | - Lorenzo A. Cingolani
- Center for Synaptic Neuroscience and Technology (NSYN), Fondazione Istituto Italiano di Tecnologia (IIT), 16132 Genoa, Italy
- Department of Life Sciences, University of Trieste, 34127 Trieste, Italy
- Corresponding author Lorenzo A. Cingolani, Department of Life Sciences, University of Trieste, 34127 Trieste, Italy.
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